european experience of small-scale and on-farm ad

European experience of small-scale and on-farm AD

SPMT09_051

Final Report

July 2010 SLR Ref: 411.01088.00006

DEFRA i 411.01088.00006 European Experience of Small-Scale and On-Farm AD June 2010

CONTENTS

EXECUTIVE SUMMARY ..................................................................................................... III

1.0 INTRODUCTION .......................................................................................................... 1 1.1 Background ....................................................................................................... 1 1.2 Project Objectives............................................................................................. 1 1.3 Report Structure and Methodology ................................................................. 2

2.0 SITUATION IN THE UK ............................................................................................... 4 2.1 AD plants in the UK .......................................................................................... 4 2.2 Policies and Regulatory Regime in the UK ..................................................... 6

2.2.1 Regulatory and Political Drivers ................................................................. 6 2.2.2 Permitting and Exemptions ........................................................................ 7 2.2.3 Economic Drivers ....................................................................................... 9

3.0 AD TECHNOLOGY AND FEEDSTOCKS .................................................................. 12 3.1 AD Technology ............................................................................................... 12 3.2 Feedstocks ...................................................................................................... 13 3.3 Gas Yields of Selected Feedstocks ............................................................... 14 3.4 Environmental Impact of AD .......................................................................... 17

4.0 PROJECT METHODOLOGY ..................................................................................... 20 4.1 Stage 1 – Key Country Selection ................................................................... 21 4.2 Stage 2 Pre-Screening – Literature Review................................................... 23 4.3 Representative Sample Selection .................................................................. 24

4.3.1 Screening criteria ..................................................................................... 24 4.3.2 Selection of representative sample .......................................................... 25

4.4 Site visit preparation ...................................................................................... 26 4.4.1 Detailed data gathering ............................................................................ 26 4.4.2 Site visit selection .................................................................................... 27

5.0 REVIEW OF FARM/SMALL SCALE AD SECTOR – BY COUNTRY ......................... 28 5.1 AD development in key European countries ................................................ 28 5.2 Current situation in identified countries ....................................................... 28

5.2.1 Austria ..................................................................................................... 28 5.2.2 Belgium ................................................................................................... 30 5.2.3 Czech Republic ....................................................................................... 31 5.2.4 Denmark .................................................................................................. 32 5.2.5 France ..................................................................................................... 35 5.2.6 Germany .................................................................................................. 36 5.2.7 Hungary ................................................................................................... 37 5.2.8 Italy .......................................................................................................... 40 5.2.9 Luxembourg ............................................................................................. 42 5.2.10 Netherlands ......................................................................................... 43 5.2.11 Portugal .............................................................................................. 44 5.2.12 Spain ................................................................................................... 46 5.2.13 Sweden ............................................................................................... 49 5.2.14 Switzerland ......................................................................................... 51

6.0 PLANT SCREENING AND SHORTLISTING ............................................................. 52 6.1 Contact Detail Availability .............................................................................. 54 6.2 Feedstock ........................................................................................................ 54 6.3 Type of AD System ......................................................................................... 56 6.4 Technical Data – Plant Performance ............................................................. 57 6.5 Energy Data ..................................................................................................... 58

6.5.1 Installed electrical CHP capacity .............................................................. 58 6.5.2 Electricity utilisation ................................................................................. 58 6.5.3 Heat utilisation ......................................................................................... 61

6.6 Other Information............................................................................................ 61

DEFRA ii 411.01088.00006 European Experience of Small-Scale and On-Farm AD June 2010

6.7 Final Site Visit Selection................................................................................. 62

7.0 FINDINGS FROM OPERATING AD PLANT VISITS .................................................. 65 7.1 Overview .......................................................................................................... 65 7.2 Key Findings from Plants Visited .................................................................. 65

7.2.1 Required Planning Permissions ............................................................... 66 7.2.2 Grants and Subsidies .............................................................................. 67 7.2.3 Development in Agricultural AD Technology ............................................ 68 7.2.4 AD Plant Performance ............................................................................. 70

8.0 KEY FINDINGS .......................................................................................................... 78

9.0 CONCLUSIONS ......................................................................................................... 83

10.0 REFERENCES ........................................................................................................... 85

APPENDICES

Appendix A: Maps of Biogas Sources in Europe

Appendix B: Available AD Plant Information by Country

Appendix C: AD Plant Data Comparator Matrix

Appendix D: Overview of Scoring System for Key Performance Indicators

Appendix E: Site Visit Protocol Template

Appendix F: Case Study Protocols

Appendix G: Most Relevant Environmental Plant Permits and Exemptions of Visited Countries

DEFRA iii 411.01088.00006 European Experience of Small-Scale and On-Farm AD June 2010

EXECUTIVE SUMMARY SLR Consulting Limited (SLR), in association with LRS Consultancy (LRS), was commissioned by Defra to examine the use, the development and the performance of small-scale/on-farm anaerobic digestion (AD) plants (150 - 400kW) in Europe. Whilst there is evidence of extensive development of the small-scale/on-farm AD sector in several European countries, particularly Germany and Austria, there is little development in this sector in the UK. In anticipation of the project aims the key objectives, as set out by Defra, for this project were:

1. Identification of a representative sample of relevant plants in Europe that deal with

wastes or a combinations of wastes specified by Defra

2. Collection of process specific data for each of the plants identified, such as applied

AD system and process performance in relation to the feedstock, but also

identification of digestate end-uses, operational issues and received subsidies

3. Data analysis on the data to evaluate the relationship between the quantity of

feedstock and the amount of biogas/energy produced and how these are influenced

by feedstock changes or technology choice

4. Compilation and data analysis on emissions from on-farm and small-scale AD sites

and to provide information with respect to waste management licensing exemptions

for small-scale / on-farm AD in the visited countries.

A geographical evaluation was carried out in order to identify the European countries that produce a significant amount of biogas from agricultural or municipal food and green waste sources, and thus may have the potential to contribute valuable data to this study. For the selected key countries an in-depth literature review was carried out in order to collate details on the overall number of AD plants in the respective countries, the overall electricity installed at these plants, operational data on individual AD plants and the legal background on renewable energy and any fiscal incentives received from the respective local governments. It is reported that there are c.5,800 AD plants in Europe, of which Germany, with c.4,500 AD plants in 2009, is by far the largest user of this technology followed by Austria (295), Italy (235) and Sweden (227). This study identified a total of 862 AD plants spread over 14 countries, of a size and feedstock type of relevance for consideration by this study. For 221 of these minimum data, such as feedstock and installed CHP engine size, was available. In order to create shortlist of c.60 AD plants a scoring matrix was developed, scoring each plant against a series of key performance indicators, such as feedstock, energy utilisation, and plant performance amongst others. The operators of the highest scoring plants were subsequently contacted to identify those that would be prepared to accommodate a site visits and to provide further plant operating data. In total 19 plants were visited in 5 different countries: Austria, Denmark, Germany, Italy and Sweden. The review showed that small-scale / on-farm AD plants typically use mesophilic low-solids digestion to process the mostly wet feedstocks and take advantage of the robustness and simplicity of the mesophillic process. Only a few plants operate in thermophilic mode. Most of the plants visited had gas storage integrated into the digester or post digester with a double membrane roof; only few sites had external gas storage holders. None of the plants visited cleaned the biogas prior to use in the CHP engines. The findings from the detailed data analysis have demonstrated a strong theoretical linkage between feedstock type and biogas/ energy production; the results from the plant visit / data collection programme largely validated the theoretical data, with some exceptions. The collated data showed that c.80% of plants operate on a mixed feedstock stream (often

DEFRA iv 411.01088.00006 European Experience of Small-Scale and On-Farm AD June 2010

including energy crops), with only c.5% of plants operating exclusively farm animal wastes, with some operating on food waste from households and commercial sources only. Plant feedstock capacities range from 3,000t/year treating energy crops to 100,000 tonnes/ year where farm manures or slurries are treated only. In general the plant operators were content with the AD technology and the plant operability, with only a few operational issues reported, mainly of mechanical nature and with no problems reported with the biological performance of the plants. However, the case study data indicated that some plants underperform with respect to biogas yield, with the likely cause being poor operational control (e.g. excessive organic loading rates, pH variations, or insufficient temperature control), leading to reduced bacteria activity and reduced energy generation. The permitting system applied across Europe was also investigated with respect to waste management licensing exemptions for small-scale/ on-farm AD in the UK, which are aimed at AD plants with a net rated thermal input1 from 0.15MW to 0.40MW. Most European countries operate under the Integrated Pollution Prevention Control Directive (2008/1/EC) for all AD plants. However, operators of AD plants treating only small amounts of waste, and waste that is considered to be of low risk, such as biodegradable waste, may apply for a Waste Management Licence (WML) exemption. Some additional regulations implemented nationally may also have an impact on the respective AD development. In Germany for example, small-scale AD plants are not required to be fitted with fixed standby gas flares, which consequently leads to uncontrolled methane emissions during gas engine downtime periods. This lack of adequate minimum plant requirements has been recognised and the issue is currently under review and discussion in Germany. The findings of this study showed that the AD Plant development generally follows the incentives offered by government. Where applicable, plant sizes depend on the highest bonus scheme rather than on the available feedstock. This is equally the case for the type of feedstocks treated and the type of renewable energy utilisation applied. Belgium‟s energy bonus payment is independent of the plant size. As a result operators are focusing on larger AD plant developments in order to make district heating schemes a viable option. Germany employed a graded bonus system, which encouraged the installation of AD plants with a net energy rating of smaller than 500kW. Significant growth was therefore reported in the small scale plant range. They also pay bonuses for energy crop treatment and for the treatment of a minimum percentage of animal farm wastes, which was consequently employed at most farms visited. In Upper Austria the requirement for plants to have a heat utilisation concept has led farmers to install woodchip or grain drying on site. For a long period Sweden offered substantial incentives and benefits for the production and the use of biomethane as vehicle fuel. Consequently, Sweden is the market leader of biomethane fuel production. These examples show that governmental incentives can heavily influence not only the choice of plant size and technology, but also the type of feedstock that is being treated. It was clear that a minimum level of funding is required to encourage the farmers to install AD plants. It was also clear that incentives focusing only on one end-product may prevent the development of certain technologies; thus incentives for both, technologies and feedstocks, have to be carefully considered prior to their implementation.

1 Net rated thermal input is the rate at which fuel can be burned at the maximum continuous rating of

the appliance multiplied by the net calorific value of the fuel and expressed as megawatts thermal.

DEFRA 1 411.01088.00006 European Experience of Small-Scale and On-Farm AD June 2010

1.0 INTRODUCTION

1.1 Background

SLR Consulting Limited (SLR), in association with LRS Consultancy (LRS), was commissioned by Defra to examine the use, the development and the performance of small-scale/on-farm anaerobic digestion (AD) plants in Europe. Whilst there is evidence of extensive development of the small-scale/on-farm AD sector in several European countries, particularly Germany and Austria, there is little development in this sector in the UK. Anaerobic digestion (AD) is the breakdown of organic matter in the absence of any free oxygen. The process results in the production of liquid and/or solid digestate and biogas. The biogas can be used for energy generation via combined heat and power (CHP) engines, or alternatively upgraded to biomethane for use as a renewable fuel. The sale of the produced electricity may help farmers to reduce energy bills or realise a small profit from exporting this energy into the grid. Additionally, the produced digestate can be used as organic fertiliser in place of artificial fertilisers, thus further reducing costs. As well as producing renewable energy the process helps reducing methane emissions by degrading and stabilising cow slurry and manure. In response to emerging policy and economic drivers (e.g. feed-in tariffs, renewable heat incentives) the EU biogas sector has expanded rapidly in recent years. However, the development of the AD sector for the production of renewable energy in the UK has so far been slow. The aim of this study was therefore to identify current best practices applied across Europe, but also to compare other countries permitting system with that of the UK. Particular focus was laid on on-farm and other small-scale AD plants with a net rated thermal input2 from 0.15MW to 0.40MW. Due to the large agricultural sector in the UK, farm-scale AD plants have the potential to significantly contribute to the production of renewable energy, and thus to help the government meet it‟s renewable energy targets of 20% by 2020, as set out in the white paper3. The European experiences and lessons learnt will provide useful context for the facilitation of the development of this particular AD sector in the UK. One proposed measure to accelerate the uptake of on-farm anaerobic digestion it is the simplification of the planning permission process and the exemption of plants with energy outputs up to 400kW from environmental permitting requirements. The European regulations generally require an Environmental Permit under the Pollution Prevention Control Directive (2008/1/EC) for all AD plants. However, operators of AD plants treating only small amounts of waste, and waste that is considered to be of low risk, such as biodegradable waste, may apply for a Waste Management Licence (WML) exemption. Another objective of this study was therefore to investigate the potential impact this regulation has on the development of on-farm anaerobic digestion in Europe.

1.2 Project Objectives

In anticipation of the project aims the key objectives, as set out by Defra, for this project were:

2 Net rated thermal input is the rate at which fuel can be burned at the maximum continuous rating of

the appliance multiplied by the net calorific value of the fuel and expressed as megawatts thermal. 3 Dti, May 2007: Meeting the energy challenge


1. Identification of a representative sample of relevant plants in Europe that deal with

various wastes or combinations of wastes, specifically considering following wastes:

a. Manure

b. Slurry

c. Plant waste

d. Food waste

e. Paper and cardboard

2. Collection of following data for each of the plants identified:

a. Type of AD system used and residency time

b. Type and proportions of feedstock and throughput of plant (in tones/annum)

c. Amount of digestate and biogas produced

d. End use of digestate and biogas

e. Subsidy schemes used (if any)

f. Operational issues (e.g. related to feedstock, outputs, emissions) and

mitigation actions taken

3. Data analysis on the data collected to provide answers to the following:

a. What is the relationship between the quantity of feedstock and the amount of

biogas/energy produced? How does this compare if the feedstock changes

(i.e. from manures and slurries to a wider range of feedstock e.g. to include

food waste) and for alternative AD systems and residency times?

b. Based on the relationship between feedstock quantity and biogas/energy

production, is there an optimum size for on-farm AD and/or small-scale AD

units, taking account of the range of feedstocks observed?

c. What operational problems have been encountered and what solutions have

been applied to overcome them? What would be the implications of these

issues in the UK context?

4. Compilation and data analysis on emissions from on-farm and small-scale AD sites to

determine the relationship between the size of the plant and emission levels.

1.3 Report Structure and Methodology

The report is presented in a methodical manner, enabling the reader gain an appreciation of the AD process, prior to learning of the AD situation and development in other European member states. The main part of the report then describes the methodology used for the data collation and plant identification, which is followed by the presentation of the core performance data and the key findings of the data analysis and the subsequent site visits. The project was undertaken through a series of tasks, designed to deliver the maximum benefit from the study whilst ensuring that the specific objectives were met. The initial stages of the project involved a detailed literature review in English, and also in Danish, German, Portuguese, and Italian in order to collate a maximum amount of data available on AD plants operating in key countries across Europe. Additional data were received from a number of AD technology suppliers and also from SLR‟s extensive in-house technology database.


In the second phase of the project the collated dataset was analysed for the amount and type of data provided. The compiled dataset was reduced to only comprise AD plants that provided a minimum amount of information, such as feedstock, installed CHP engine size, and AD plant operator or vendor. The key task of the next phase was to develop a representative sample of relevant plants that may be used as the basis for a subsequent plant site visit selection. A scoring matrix was developed scoring each plant against a series of key performance indicators matching the objectives of this study, particularly with regards to feedstock and energy generation. The aim of this task was to produce a representative sample list comprising around 50 AD plants that would potentially provide more detailed data for this study during a site visit. In preparation for the site visits, a site visit draft protocol was sent to the top-ranking operators (based on the plant scoring system) and the level of operator interest in participating in this research was investigated. The returned questionnaires were evaluated together with information received via the phone directly and were used to select a total of 12-16 plants for a subsequent site visit. Site visits were chosen strategically in order to get practical examples from a number of countries. The final stage of the project included an appraisal of the collated data, providing a detailed overview on the preferred types of AD technology used within the agricultural sector in Europe, the feedstocks used and the associated energy potential, and the electricity and heat generation. It also shows how national planning requirements influence the design and use of AD operations and how the main plant emissions are controlled. The report concludes with key findings and lessons learnt from the use of small-scale and on-farm AD systems in Europe, which are of relevance for the facilitation of the development of this AD sector in the UK.


2.0 SITUATION IN THE UK

In recent years the EU biogas sector has expanded rapidly in response to emerging policy and economic drivers (e.g. feed-in tariffs, renewable heat incentives). Most countries now pay renewable energy producers a commodity amount per kWh of electricity and/or heat produced and/ or exported. However, the AD development for the production of renewable energy in the UK has so far been slow. This section provides an overview on operational AD plants in the UK, the political and economic drivers to boost the use of AD, and UK‟s current permitting system.

2.1 AD plants in the UK

Anaerobic digestion has been used in the wastewater treatment industry for many years in the UK and there are over 1,000 plants treating sewage sludge. Although experiencing an increase in the recent years the uptake of anaerobic digestion for other organic wastes is still slow. By the end of 2006 around 30 agricultural AD plants had been built4 and despite plans for another 60 plants only 37 anaerobic digestion plants were listed in the UK5 by the end of 2009.

Figure 2-1

Anaerobic digestion plants in the UK5

Of these 37 registered plants 25 were classed as “on-farm” AD plants with net energy outputs ranging from 23 to 1,500kW, however only half of the plants stated the net energy output; of these only three were in the range of 150-400kW. Most plants use cow manure or cattle/pig slurry as feedstock, often mixed with maize or grass silage and occasionally also accepting food waste.

4 Jeremy Eppel, defra, 2007: Presentation on UK experience on using AD in agriculture, Buenos

Aires. 5 http://www.biogas-info.co.uk/index.php/ad-map

http://www.biogas-info.co.uk/index.php/ad-map


Details on the applied AD systems were not available, although it is expected that the majority of systems will be based on wet anaerobic digestion, due to the low dry solids content of the cattle manure/slurries feedstocks. Equally it can be assumed that most commercial plants operate in the mesophilic temperature range (33-38°C) as the process is more stable and therefore easier to control; it also requires less energy than plants operating in the thermophilic range (55-58°C). The reasons for the slow uptake of AD treatment in agriculture are mainly commercial, but may also be down to limited technical knowledge or a lack of information and awareness. The Environment Agency has acknowledged the potential benefits of liquid digestate as fertiliser and supports anaerobic digestion as one of the ways of diverting biodegradable wastes from landfill, recovering value from them and reducing emissions of greenhouse gases6. Equally, the UK government is strongly supporting the development of anaerobic digestion with the additional aim to recover renewable energy from the produced biogas. However, the application of AD products to land may also present risks to the environment and therefore has to be regulated. Overall, as outlined in the Defra AD Implementation Plan for England (March 2010)7, the Government‟s aim is to create a framework for action in the public and private sector to accelerate the uptake of anaerobic digestion through:

o Creating the right long term economic framework;

o Ensuring that the regulatory framework strikes an appropriate balance between

encouraging cost-effective growth in the use of anaerobic digestion and ensuring protection of the environment and those operating anaerobic digestion facilities;

o Building capacity by increasing awareness and understanding of the use of AD technology and its products;

o Undertaking research to improve knowledge of the use anaerobic digestion technology and its products;

o Sharing experience and learning from experience of other countries; o Assessing progress to identify where actions are working or where changes are

needed.

6 Environment Agency website, “Our view on Anaerobic Digestion”, accessed on 14 June 2010,

http://www.environment-agency.gov.uk/business/sectors/32601.aspx 7 Accelerating the Uptake of Anaerobic Digestion in England: an Implementation Plan, Defra, March

2010.

http://www.environment-agency.gov.uk/business/sectors/32601.aspx


2.2 Policies and Regulatory Regime in the UK

This section identifies the key of the overarching framework of UK and European policy of relevance to AD treatment. The key relevant drivers are summarised in this sub-section.

2.2.1 Regulatory and Political Drivers

The key regulatory and political drivers are: Regulatory Drivers

o Landfill (England & Wales) Regulations 2005; o Landfill Allowance and Trading Scheme Regulations 2004; o Environmental Permitting Regulations 2010 (England and Wales); Waste

Management Licensing Regulations 2003 (Northern Ireland); Waste Management Licensing Regulations1994 (Scotland) and Waste Management Licensing Amendment Regulations 2006 (Scotland)

o Animal By-Product (England) Regulations 2005 and revised 2009; o Anaerobic Digestate Quality Protocol (2010) Political drivers o Waste Strategy for England 2007; Scotland's Zero Waste Plan 2010; Towards

Resource Management: The Northern Ireland Waste Management Strategy 2006 - 2020; Waste Strategy 2009 – 2050: Towards Zero Waste (Wales)

o Accelerating the Uptake of Anaerobic Digestion in England: an Implementation Plan (March 2010)

o Energy Act 2008 (arising from Energy White Paper 2007); o Renewables Obligation Order 2002 and revised Renewables Obligation Order 2007

and 2009. Additionally, the following European Legislation is affecting the UK biogas sector:

o EU Waste Framework Directive (Revised Directive 208/98/EC); o EU Landfill Directive 1999/31/EC; o EU Animal By Products Regulation (1774/2002/EC) o Integrated Pollution Prevention and Control Directive (2008/01/EC);

In addition, the European Commission has produced a working document titled „ Biological Treatment of Biowaste‟ to improve the management of biodegradable and help meet the Landfill Directive 1999/31/EC targets. The bulk of UK waste management policy and legislation is drawn directly from European legislation, transposed into UK statute. The focus of the legislation identified here lies strongly on the support of the development of AD treatment processing capacity for the treatment of organic materials with the aim to divert organic waste from landfill and to recover energy. With specific reference to encouraging on-farm anaerobic digestion of manures and slurries, a revised exemption regime has been introduced in England and Wales in 2010 which includes a new exemption for small on-farm anaerobic digestion facilities (for more details refer to Section 2.2.2). In addition, “the Pig Meat Supply Chain Task Force” has agreed that

http://www.ni-environment.gov.uk/wms.17.pdf



http://www.google.co.uk/url?sa=t&source=web&cd=1&ved=0CB0QFjAA&url=http%3A%2F%2Feur-lex.europa.eu%2FLexUriServ%2FLexUriServ.do%3Furi%3DCONSLEG%3A2002R1774%3A20070724%3AEN%3APDF&rct=j&q=Animal+By-Products+1774%2F2002&ei=yfsVTLS8HYfu0wSt4pGACg&usg=AFQjCNF5PHglZgv4gS9bgutTzMUxt4VPlw


the pig industry, with support from Government and its Agencies, will review regulatory requirements […] in order to stimulate and facilitate uptake of on-farm anaerobic digestion”8.

2.2.2 Permitting and Exemptions

England and Wales In England and Wales operators of anaerobic digestion facilities with a minimum size are required to obtain an environmental permit for the operation of the plant under the Environmental Permitting (England and Wales) Regulations 2007 (SI2007 No. 3538), in order to minimise the risk to the environment. Defra, the Environment Agency and the Welsh Assembly Government have recently reviewed the requirements for exemption from environmental permitting with the aim to encourage on-farm anaerobic digestion of manures and slurries. The new regime, which was came into force in April 2010, includes a new exemption for on-farm anaerobic digestion and the burning of the biogas in an appliance with a net rated thermal input of less than 400kW. Additionally, AD operations that are not exempt are able to apply for a newly developed “standard permit”, provided the anaerobic digestion activity is covered by a standard set of rules. The intention is to make applications simpler and also less costly compared to bespoke permits. Another measure to accelerate the uptake of on-farm anaerobic digestion is the simplification of the planning permission process. One proposal is to remove the need of planning permission altogether for “the erection of structures for housing anaerobic digestion systems and associated waste and fuel stores “, although this would be limited to AD plants that only treat wastes generated and treated on the same farm. Scotland In Scotland, SEPA does currently not consider manures and slurries sent to AD as waste and therefore such on-farm AD activities operate unlicensed. The requirement for environmental permits under the Pollution Prevention Control (PPC) regulations or the Waste Management Licensing (WML) regulations depends upon the end-use of the material (recovery or disposal) and the tonnage treated, as is shown in Figure 2-2.

8 Accelerating the Uptake of Anaerobic Digestion in England: an Implementation Plan, Defra, March

2010.


Figure 2-2 Current Scottish licensing arrangements for the anaerobic digestion of waste9

However, the revised Waste Framework Directive (2008/98/EC) has now been enacted and must be transposed by December 2010. Article 2 of this revised Waste Framework Directive specifically captures manures and slurries sent to „biogas‟ plants, which may require a change in the Scotland‟s position on manure and slurry treatment. In addition, the Scottish Government is consolidating the Waste Management Licensing Regulations (Scotland) 2010, in which it is proposed to exempt anaerobic digestion from the licensing requirements, including the on-farm treatment of manure and slurries. It has to be noted however, that the final form of this document has not yet been approved. Northern Ireland Under the Waste and Contaminated Land (Northern Ireland) Order 1997, a Waste Management Licence is required to authorise the deposit, treating, keeping or disposal of controlled waste on any land. Paragraph 13 allows the composting and/or the storage of certain biodegradable wastes that can be applied to land for the benefit of agriculture or ecological improvement to be undertaken under an exemption regime. For this to apply, the total quantity of waste treated or stored, at the place where composting is to be carried out, must not exceed 200 tonnes at any one time. The 200 tonne limit includes all wastes onsite prior to treatment.

9 Provided by Andrew Sullivan, SEPA per e-mail


Additionally, if animal by-products or catering waste are to be used as feedstock for anaerobic digestion, the operator must apply for approval from the Department of Agriculture and Rural Development (DARD) and, if the facility is to generate gas for heat or electricity, a pollution prevention and control permit or waste management licence is also required. An exemption is applicable to facilities that have an aggregate net thermal input of less than 0.4 megawatts. European Union At European level, current regulations generally require an Environmental Permit under the Integrated Pollution Prevention Control Directive (2008/1/EC) for all AD plants. However, operators of AD plants treating only small amounts of waste, and waste that is considered to be of low risk, such as biodegradable waste, may apply for a Waste Management Licence (WML) exemption. The potential impact of this requirement and the availability of WML exemptions on the development of on-farm anaerobic digestion has been investigated as part of detailed AD plant review and the subsequent site visits and is discussed in more detail in Section 7. The IPPC Directive is implemented in England and Wales by the Environmental Permitting (England and Wales) Regulations 2010.

2.2.3 Economic Drivers

There are two main economic drivers that may promote the operation of on-farm AD and the utilisation of the produced biogas as renewable energy: government incentives and to a lesser extent operational profit. To date the renewable energy sector in Europe is dominated by the use of CHP engines to produce heat and electricity. This is encouraged by government incentives, such as financial benefits and grant support. Most countries pay the renewable energy producer a commodity amount per kWh of electricity and/ or heat produced. For example in the UK, this is currently two times one “ROC” (Renewable Obligation Certificate), with each valued at 3.7p/kWh plus a small payment associated with the Climate Change Levy, which together totals 7.8p/kWhr (8.7ct/kWhr), for renewable electricity produced. The UK Government has recently introduced the Feed-in Tariff for microgeneration products. The Feed-in Tariff (FIT) is a financial support scheme introduced by the Government from April 2010 to encourage the uptake of small-scale microgeneration technologies that generate electricity. The scheme is also known as the 'clean energy cashback plan'. British Feed-in Tariffs will consist of two parts, a generation tariff and an export tariff.

Generation tariff - the electricity supplier will make a fixed payment to the householder for every kilowatt hour (kWh) of electricity they generate.

Export tariff - the electricity supplier will pay a fixed amount for every kWh of electricity exported by the householder back to the electricity grid.

The proposed tariff levels for anaerobic digestion are illustrated in the following table.

Table 2-1

Proposed tariff levels

Technology Scale 2010-11 Tariff

p/kWh

Annual

change2

AD1

(electricity) <5MW 9 0

AD1

(CHP1

) <5MW 11.5 0


1 Abbreviations: AD=Anaerobic Digestion, PV=Photovoltaic

(solar), CHP=Combined heat and power, RO=Renewables

Obligation

2 The annual 'degression'

In Germany, the equivalent incentive is 11.67ct/kWh. This payment is in addition to the electricity and heat sales price, thus allowing the operators to realise considerable revenue from energy production. From April 2011 there will also be feed-in tariffs for heat under the renewable heat incentive (RHI). The consultation process on RHIs has now been closed and it is proposed to incentivise the use of renewable heat from anaerobic digestion with 5.5p/kWh for medium sized installations (up to 500kW, depending on the heat end-use). The following example shows to which extent farmers may benefit financially from the feed-in tariffs/ ROCs. The example is based on a small-scale AD unit with a 250kW CHP engine installed:

Table 2-2 Example: Governmental incentives paid for renewable energy from AD

Farm

Livestock

Feedstock

1000 cattle

Cow manure

Methane potential cow manure:

24-30m3

/t input

Energy potential methane:

10kWh/m3

AD Plant

Plant Capacity

Installed CHP engine

Electrical engine efficiency

Thermal engine efficiency

20,000t/a

250kWel

38%

40%

Energy Production

Total energy production

Electricity production

Heat production

4,800MWh

1,824MWh1

1,920MWh1

or 228kW

or 240kW

Governmental incentives

Electricity:

ROC/LEC

Electricity sales price

Total income/kWh produced5

Total income electricity2

Heat:

RHI feed-in tariff

Heat sales price

Total income/kWh produced3

Total income heat4

8.7p/kWh

7p/kWh

15.7p/kWh

£286,368/a

5.5p/kWh

0p/kWh

5.5p/kWh

£52,800/a

Total income from energy production £339,168/a

Notes: 1) at 90% (8000hrs) engine availability 2) Assuming all electricity is sold; parasitic electricity requirements (~6-8%) not considered 3) Heat used for own farm buildings in winter 4) heat not utilised in summer, i.e. total heat utilisation 50% 5) Electricity sales price April 2010


The example shows how the anaerobic digestion of farm animal wastes may contribute to the financial farm management. The energy potential is depending on the feedstock and even significantly smaller sized plants may generate a similar amount of energy. New plant installations currently benefit from the above incentive payments for a period of 20 years. Additionally the farmer will be able to use the produced digestate as organic fertiliser, thus providing an additional cost saving.


3.0 AD TECHNOLOGY AND FEEDSTOCKS

3.1 AD Technology

The term „AD‟ covers a wide range of technologies that vary considerably in their design, configuration, engineering and performance. It is important to note that they are not uniform in their process performance and outputs and that the most appropriate technology is selected with the specific project objectives, feedstocks and site location parameters in mind. The main AD processes available can be differentiated into:

single stage / two stage;

low-solids (wet) / high-solids (dry) digestion;

mesophilic / thermophilic; and

batch flow / plug flow / continuous flow (completely mixed) process. The digestion process essentially consists of two steps. During the hydrolysis and acetogenesis the organic waste is broken down into glucose, amino acids and then fatty acids, acetic acids and hydrogen. In the second stage, the methanogenesis, these products are converted into methane-rich gas. Single stage AD plants only comprise of one digester. Hence, both biological process stages take place in the same reactor. The advantage of single stage processes are the comparatively simple process configuration, the smaller footprint required and the reduced investment costs. However, both stages require different optimum conditions (i.e. different pH), which prolongs the required residence time inside the reactor to achieve similar levels of degradation achieved in i.e. two-staged reactors. In two-staged processes the hydrolysis/ acetogenesis is separated from the methanogenesis to compliment the different biological process requirements. The provision of optimum conditions in each reactor for the two stages results in reduced residence times or allows to achieve increased degradation at the same residence time. It also allows better control of the biological processes, which may result in higher gas yields. The disadvantages of two-staged processes are the more complex process control, the bigger footprint required and the increased energy requirements. Feedstock with a dry solids (DS) content of up to 15% is generally treated in wet AD systems. Hence, most agricultural plants treating manure and slurries are based on this system. Feedstocks comprising a large amount of comingled food and garden waste, silage or energy crops tend to have an increased dry solids content for which dry AD systems may be more appropriate. Mesophilic plants are operated between 33-38°C, thermophilic plants are operated at around 55-58°C. The biological degradation process speeds up with increasing temperatures, which leads to reduced retention times or higher gas yields that can be achieved with thermophilic digestion processes. At the same time, the high temperatures allow the hygenisation of the treated material in accordance with the Animal-By-Product Regulations. The advantages of the mesophilic process are that it is less susceptible to variations in temperature and pH concentrations and that less energy is required to heat the digester(s) therefore providing increased revenue potential.


The most common AD technology found in agriculture is based on wet, mesophilic digestion due to the generally low percentage dry solids content of the feedstocks and the relative insensitivity of mesophilic bacteria to variations in the feedstock. There is currently no clear trend on the preferred number of treatment stages. This seems to relate to the preference of the individual technology supplier rather than to the overall effectiveness of the various systems. Single staged systems (digester and digestate storage tank only) use prolonged residence times in the digester to achieve a high degree of biostabilisation, whilst multi-staged AD systems additionally include a post-digester, splitting the overall residence time between these two reactors. Separating the digestion process into 2 phases (e.g. hydrolysis and methanogenesis) has the advantage that the two different bacteria groups involved in these stages can work at optimum conditions, thus reducing the required overall residence time for similar gas yields. However, in practice it was found that these 2 stages were combined rather than being controlled separately, especially on the small-scale agricultural AD plants.

3.2 Feedstocks

The focus of this study was laid on using AD technology for the treatment of agricultural wastes rather than applying this technology in competition to other food waste treatments or for the sole purpose of renewable energy production. AD plants using following feedstocks, or a combination of these, were therefore targeted primarily:

d. Manure

e. Slurry

f. Plant waste

g. Food waste

h. Paper and cardboard

In continental Europe, particularly in Austria and Germany, on-farm AD is mainly used for energy recovery, thus treating energy crops, such as maize, corn-cob mixes, or a variety of silages. Mono feedstocks are rare and often manure and slurries are added to the mixture of feedstocks and vice versa, as the digestion of manures and slurries may be accelerated by the addition of carbon sources contained in energy crops and food waste. Around 80% of Europe‟s small-scale AD plants are located in Austria and Germany, making it very difficult to identify AD plants that do not include energy crops as part of their feedstock. Also, it can be expected that AD technology has undergone a significant development here to best suit farm conditions and feedstocks due to the extensive use of AD in these countries. It was therefore seen imperative to include AD plants using energy crops, as long as at least a significant proportion of the feedstock includes elements from the above list. Due to the common practice of treating mixed rather than mono feedstocks it was difficult in practice to evaluate the anticipated biogas production per tonne of waste feedstock (usually expressed per tonne of volatile solids content in the feedstocks) by the individual types of waste. Readily available biogas production rates from literature were therefore used as an aid to evaluate the performance of various AD feedstocks and systems.


3.3 Gas Yields of Selected Feedstocks

This section gives an overview of the biogas potential of selected waste feedstocks commonly used in British agriculture and of selected energy crops, as used in continental Europe. The main waste products in agriculture are animal slurries/ manure (cattle, pig, and chicken) and harvest residues from crop growth, such as wheat, barley, oats, rapeseed, potatoes and sugar beets. Other wastes may come from industrial sources, such as brewery or dairy wastes, animal residues, or communal wastes such as paper & card and food and garden wastes from households or from commercial sources. The latter waste fractions are not expected to be treated in significant quantities in small-scale AD plants with net energy outputs of <400kW. Table 3-1 gives an overview of the average waste characteristics of the most common feedstocks.

Table 3-1 Waste characteristics of selected AD waste feedstocks10

Feedstock DS VS Biogas potential CH4-

content

[%] [%] [m3/t fm] [m

3/t VS] [%]

Agricultural crops/ cereals

Wheat 86 92 - 380 52

Barley 86 94 - 427 52

Oats 85-90 85-89 - 250-350 52

Rapeseed (winter) 85-90 85-89 - 250-350 52

Rapeseed (summer) 86 92 - 350 52

Maize 86 72 - 500 52

Animal wastes

Cattle manure 20-25 68-90 40-50 210-500 60

Cattle slurry11

,12

6-11 70-85 20-30 200-500 60

Pig manure 20-25 75-80 55-65 270-450 60

Pig slurry10

2.5-9 60-85 20-35 300-700 60-70

Chicken manure 25-32 63-80 70-90 250-450 60

Commercial/ Industrial wastes

Brewery water 20-25 70-80 105-130 580-750 59-60

Brewery yeast 10 92 - 723 62

Sugar beet 22-26 95 60-75 250-350 70-75

Vegetable plants/ flowers 14 83 - 620 56

Abattoir waste cattle 33 80-90 20-60 200-400 58-62

Abattoir waste pigs 30 78-86 20-60 250-450 60-70

10

Universitaet Rostock/ Institut fuer Energetik und Umwelt, Jan 2007: Biogaserzeugung durch Trockenvergärung von organischen Rückständen, Nebenprodukten und Abfällen aus der Landwirtschaft

11

,11

Encrop, 2008: Leitfaden Biogas 12

Bayrische Landesanstalt fuer Landwirtschaft, jan 2010: Biogas-Pilotanlagen Bayern Messergebnisse


Feedstock DS VS Biogas potential CH4-

content

Fruit juice 25-45 85-95 150-280 590-680 65-70

Municipal wastes

Food waste (household) 22-30 50-80 80-120 150-600 58-65

Supermarket food waste 21 50-80 - 500-600 50-53

Grass cuttings 12 83-92 150-200 550-680 55-65

Green waste 21 94 - 450-550 55

Paper & card (mixed)13

70-80 86-92 100-130 170-220 46-50

Energy crops

Sugar beet leaves 15-18 75-80 ~70 550-600 54-55

Haulm 20-25 78-80 - 500-600 50

Hops 17 77 - 570 54

Grass silage 30-45 85-96 170-200 500-600 51-55

Maize silage 20-35 85-95 170-200 450-700 50-55

The energy potential of these feedstocks is calculated by determining the volume of methane produced during the digestion process. Feedstocks with increased dry solids (DS) contents and a high content of easily degradable (volatile) solids (VS) have a higher biogas potential, and are therefore potentially more suitable for energy generation. The feedstock characteristics summarised in Table 3-1 show that the biogas potential of common agricultural wastes such as animal wastes (slurries, manure) is significantly lower than for example the biogas yield from food wastes or energy crops, such as maize or grass silage. To visualize the difference in projected biogas generation yields by feedstock, the average methane production (Nm3) per tonne input of selected feedstocks14 is illustrated in Figure 3-1. The projected methane yield is based on the literature values stated in Table 3-1.

13 Wiemer, K., Kern, M., 1996: Technisch-wirtschaftliche Umsetzung von Ressourcen- und TA-

Siedlungsabfallbezogenen Abfallwirtschaftskonzepten im regionalen Verbund 14

Where range was provided average value of range was used for the calculation.


0

50

100

150

200

250

300

Wheat Rapeseed

(summer)

Cattle manure Cattle

slurry[1],[2]

Pig manure Chicken

manure

Paper & card Foodwaste

(household)

Green waste Gras silage

Feedstock

Meth

an

e p

rod

ucti

on

(N

m3/t

)

Figure 3-1

Specific methane yield/ tonne input of selected feedstocks

The projected methane generation from the selected feedstocks confirms that increased biogas yields can be achieved with agricultural/ energy crops and food and green wastes rather than with traditional farm wastes, such as manures and slurries. It has to be noted however that the achievable biogas utilisation depends on a combination of factors. Optimal biogas utilisation requires careful plant operation, which includes feedstock preparation (e.g. shredding of crops and green waste to increase the surface area for biological activity), pH control (to prevent acidification), optimised hydraulic residence times (to allow for sufficient biodegradation within the digester, without using excessive digester volume), limited organic loads (to prevent excessive loads of fatty acids within the reactor, which result in reduced biogas and methane yields and may even destroy the bacteria population), dry solids control (to maintain the mixing ability within the digester), and temperature control (to suit the bacteria population). Sub-optimal operation caused by any of these plant parameters may lead to reduced biogas yields, independent of the feedstock of feedstock combination. Pure methane has an energy value of 9.97kWh/Nm3. (dry, 0°C and 1013mbar). Converting the produced biogas into electricity via CHP engine this results in electricity productions from c.50kWh/t (cattle slurry) to 1,080kWh/t using rapeseed, based on an average electrical engine efficiency of 39%. Therefore the achievable methane production and the associated energy potential impact directly on the potential profitability of the plant and thus, a mixture of feedstocks may be required to produce sufficient biogas for AD plants to become economically viable. AD plant economics were not scope of this study and are therefore not discussed in further detail. However, to a limited extent, economic viability of farm operated AD plants is discussed as part of the case studies in Section 7.


3.4 Environmental Impact of AD

The key products of anaerobic digestion are biogas and digestate in solid and/ or liquid form. Secondary products in form of electricity and/ or heat or even biomethane for use as a fuel can be derived from the produced biogas. The emissions are generally limited to odour and noise. Should the operator use energy crops as feedstock the plant will also have an impact on land take. The environmental impact of all these factors is briefly outlined below. Solid and/ or liquid digestate produced from non-waste inputs (e.g. farm wastes) or from source-segregated biowaste as specified in Section 2 of the Quality Protocol15, and source-segregated biowastes that have been treated in accordance with the requirements of PAS11016 may be used as biofertiliser on agricultural land. The degradation of carbon compounds during the digestion process results in a reduced dry solids content of the digestate material and a concentration of mineral nutrients, especially nitrogen (ammonium), phosphorus, and potassium (N, P, and K). The digestate is therefore well suited as an alternative to artificial fertilisers. The actual concentration of these nutrients is dependent on the input material. The digestate requires no additional treatment and can be spread directly to land. Using the minerals naturally comprised within the digestate instead of artificial fertilisers as plant feed on agricultural land therefore contributes to a sustainable closed loop plant operation with regards to nutrients. It has to be noted however, that the digestate would likely be classed as “readily available N manures”. The material would therefore be subject to Nitrogen Vulnerable Zone (NVZ) regulations and thus, closed periods for spreading may apply, depending on the local area. Still widely discussed is the anaerobic digestion of energy crops, especially those that are specifically grown for the production of renewable energy via AD, as they use land that would otherwise be available for food crops or as grazing land. In addition to the extra land take required, energy crops produce greenhouse gas (GHG) emissions during growth, transport and silo storage. In comparison, the capture of e.g. cow manure greatly reduces GHG emissions and does usually not require additional transport. The use of energy crops, such as maize silage leads to a reduced requirement of fossil fuels and also reduces GHG emissions, albeit to a smaller extent; it may however contribute to soil acidification due to elevated ammonia and nitrous oxide levels in the fertilisers required for the crop growth. Ammonia may also be released into atmosphere during digestate storage and its application to land, independent of the actual feedstock. The other main source of emissions is methane escaping from leakages, uncovered digestate storage tanks and CHP exhaust air. The primary emission sources from anaerobic digestion are summarised in Table 3-2.

15 WRAP, 2010: Quality Protocol Anaerobic Digestion - The quality protocol for the production and use of quality

outputs from anaerobic digestion of source-segregated biodegradable waste

16

PAS110:2008: Specification for whole digestate, separated liquor and separated fibre derived from the anaerobic digestion of source-segregated biodegradable materials


Table 3-2 Primary emission sources of anaerobic digestion processes17

Location Source of Emission Available data

Silo/ feedstock storage Emission to air during feedstock storage in open silo (CO2, N2)

Estimate 5-20% silage loss; usually through leachate water, which can be added to digester

Feedstock tanks

Slurry tanks often uncovered – emission of ammonia, nitrous oxides, and methane No data available

Digester Biogas transport and CHP

1.8% methane loss wrt produced methane (excl feedstock/ product storage tank)

Digestate storage Methane emission from uncovered tanks

Up to 10% methane loss

reported18

Digestate use Emissions expected, but little data available

ammonia19

40 %

Small amount of nitrous oxides and methane

The utilisation of the produced biogas as renewable energy in the form of heat and electricity or even as substitute fuel greatly enhances the environmental benefits of anaerobic digestion. These benefits become clear when a life-cycle assessment (or more specifically, an evaluation of the global warming potential, better known as the “carbon footprint”) is carried out for the production of renewable energy produced via AD. Such life cycle assessments consider all inputs and outputs from “well-to-wheel”, e.g. including the “production” of the waste feedstock, the required transport, and materials required for the operation of the plant, AD plant emissions, transport for end-use, and energy savings made using renewable fuel and the organic fertiliser, etc. The calculated global warming potential can then be compared to e.g. the carbon footprint for producing a similar amount of energy using fossil fuels. Many of these assessments have been carried out for AD plant operations, including its use on farms. The results of one study20 are shown as an example here (Figure 3-2), highlighting the different environmental benefits associated with the use of animal slurry or energy crops.

17

Universitaet Rostock und Institut fuer Energetik und Umwelt, 2007: Biogaserzeugung durch Trockenvergärung von organischen Rückständen, Nebenprodukten und Abfällen aus der Landwirtschaft; Abschnitt 2

18

Amon et al. 2004, Kryvoruchko 2004, DBU 2006

19

ALFAM Modell: Søgaard 2002, DBU 2006 20

Sven Gaertner: Sep, 2009: Tagungsband: Biogas in der Landwirtschaft-Stand und Perspektiven („Biogas in agriculture – actual situation and perspectives“)


ADVANTAGE DISADVANTAGE ADVANTAGE

Figure 3-2 Results of life cycle assessment for the biogas production from

a) maize silage and b) cow slurry21

The assessment shows that the anaerobic digestion of slurry has environmental benefits (“Vorteil”) over the energy production using fossil fuels in all areas, namely energy savings (“Energieeinsparung1”), Global warming (“Treibhauseffekt2”), nutrional benefit (“Naehrstoffeintrag3”), acidification (“Versauerung4”), photo smog (“Fotosmog5”), and ozone depletion (“Ozoneabbau6”). In comparison the use of maize silage does also have some disadvantages over the energy production using fossil fuels, although the global warming potential is still greatly reduced.

21 Sven Gaertner, 2009: Wie oekologisch ist Biogas? (How ecological is biogas?) Guelzower

Fachgespraeche, Band 32: Tagungsband „Biogas in der Landwirtschaft. Stand und Perspektiven“

Maize silage Cow manure


4.0 PROJECT METHODOLOGY

This section of the report sets out SLR‟s methodology and results from the process of identification, screening and short-listing of small scale AD plants operating in Europe. The screening process was designed to produce a representative list of AD plants in Europe, providing key operating performance parameters for a variety of feedstocks, as set out in Defra‟s specification. The operators of the shortlisted AD plants were subsequently contacted to investigate their willingness to facilitate a site visit. The results of the detailed data review and of the site visits are described in Section 5. An overview of the sequential methodology used in the AD plant short-listing process is set out in Figure 4-1.

Figure 4-1

AD plant selection methodology flowchart

Stage 1: Geographical evaluation

Identification of key countries in Europe and number of AD plants in each country (~6000 in total)

A) AD plants in selected key countries where basic data are available (862)

B) AD plants that match, as a minimum, i) the net energy range of 150-400kW, and/or

ii) defra‟s feedstock specification (221)

Stage 2 pre-screening: Detailed literature review, including full internet/

web-based research, in-house database & contacting AD technology suppliers

Stage 3: Screening by Scoring Matrix

Representative list of highest scoring AD plants over a range of categories (64)

Stage 4: Confirm willingness of

operators to facilitate site visit

Undertake Site visits (12-16)


4.1 Stage 1 – Key Country Selection

There are currently 34 independent states in Europe; for many of these, little or no data is available about small- or farm-scale anaerobic digestion plants that also include energy generation. The initial task was to identify key countries with the potential to contribute valuable data to this study. The focus of the study was on countries which:

a) produce a significant amount of biogas from agricultural or municipal food and green waste sources; and

b) have similarities with the UK‟s agriculture in terms of crop and animal farming culture. The basis of the geographical evaluation was the comprehensive list of biogas sources and quantities in Europe in 2008, published on the Eurobserv‟er22 website. The results for the biogas production in the European member states are shown in Table 4-1.

Table 4-1 Primary production of biogas (ktoe1) in the European Union 2007 and 2008

2007 2008

Landfill

Gas

Sewage Sludge

Gas Other

Biogas Total Landfill

Gas

Sewage Sludge

Gas Other

Biogas Total

Germany 346,3 386,9 2925,9 3659,1 343,9 394,1 2937,8 3674,8

United Kingdom 1393,1 191,3 0,0 1584,4 1416,9 220,2 0,0 1637,1

France 338,5 51,8 28,6 418,9 379,3 44,2 28,5 452,0

Italy 314,7 2,1 71,1 387,9 324,7 4,2 81,1 410,0

Austria 4,8 5,8 206,3 216,9 4,8 4,8 222,8 232,4

Netherlands 48,4 47,7 79,9 176,5 44,4 48,9 132,5 225,7

Spain 116,1 49,1 27,3 192,4 157,0 19,7 26,6 203,2

Poland 21,0 43,0 0,6 64,7 34,2 95,0 2,6 131,7

Sweden 24,9 52,5 19,1 96,5 23,0 57,3 22,8 103,0

Denmark 7,2 20,7 65,6 93,5 6,4 20,2 67,2 93,8

Czech Republic 31,0 31,1 14,1 76,2 29,4 33,7 27,0 90,0

Belgium 48,9 4,1 26,4 79,5 46,7 7,5 33,4 87,6

Finland 27,6 12,3 1,8 41,7 30,7 11,9 2,4 45,0

Ireland 23,9 7,9 1,7 33,5 25,9 8,1 1,4 35,4

Greece 29,6 5,4 0,3 35,3 28,3 5,9 0,2 34,4

Portugal 0,0 0,0 15,8 15,8 0,0 0,0 23,0 23,0

Slovenia 7,6 0,6 3,8 11,9 8,2 3,1 2,7 14,1

Hungary 2,1 1,3 3,4 6,7 2,4 1,7 7,0 11,1

Luxembourg 0,0 0,0 9,1 9,1 9,1 0,0 10,9 10,9

Slovakia 0,2 6,8 0,5 7,5 0,2 9,5 0,6 10,3

Latvia 5,4 2,2 0,0 7,5 6,6 2,2 0,0 8,8

22 Eurobserv‟er – etat des energiesrenouveable en Europe – Edition 2009


2007 2008

Lithuania 0,0 1,6 0,8 2,5 0,4 1,7 0,9 3,0

Estonia 2,8 1,4 0,0 4,2 2,0 0,9 0,0 2,8

Romania 0,0 0,0 1,3 1,3 0,0 0,0 0,6 0,6

Cyprus 0,0 0,0 0,2 0,2 0,0 0,0 0,2 0,2

TOTAL EU 2794,5 925,3 3503,3 7223,5 2915,3 994,7 3632,1 7542,1

Note: 1ktoe = 11,630MWh

The tonnages listed under “other biogas” refer to biogas from decentralised agricultural plants, municipal solid waste plants and combined heat and power (CHP) plants. Based on the amount of “other biogas” available, key countries were selected for further research. These are listed below (also see Figure 4-2 and Appendix A):

o Austria

o Belgium

o Czech Republic

o Denmark

o France

o Germany

o Hungary

o Italy

o Luxembourg

o Netherlands

o Portugal

o Spain

o Sweden

o Switzerland

Figure 4-2 Selected European Countries for further AD research

Countries without any sources of “other biogas” or countries with only minor amounts available (the threshold was set at 10ktoe or 116,300MWh) were discounted from further review. Despite the apparently small biogas productions from agricultural or municipal waste Hungary was also carried forward into the next stage, as its biogas production from these sources was effectively doubled between 2007 and 2008. Switzerland was not part of the Eurobserv‟er biogas study but was also added to the list, as it is known to also be very active in the anaerobic digestion sector.


4.2 Stage 2 Pre-Screening – Literature Review

In Stage 2 the focus was on the actual plant data available for the identified from the selected key European countries. The starting point of the AD plant research was an in-depth literature review. A detailed search of data provided in literature, on the internet and by phone was carried out in order to collate a comprehensive long-list of AD plants in the selected European countries. Agricultural, governmental, and environmental departments of each country were contacted in order to obtain details on:

a) the overall number of AD plants in the country by the end of 2009; b) the overall installed electricity at these plants, c) statistics of individual AD plants, and d) the legal background on renewable energy and the fiscal incentives received from

the respective local governments.

There are only a few countries with comprehensive lists of AD plants in the country. Often these statistics are only kept on a county wide basis or, where existent, by the relevant national biogas association. Literature review was used where no statistical data were available from local institutions. Table 4-2 shows the approximate total number of AD plants in each country in 2009 and the total amount of energy produced from these plants in the same year.

Table 4-2 Number of identified AD plants and energy production in key European countries

Country

Number of AD plants

2009* Energy produced 2009

(MWel)

Austria 295 77.2

Belgium 30 55.0

Czech Republic 209 (91) 54.0

Denmark 77 28.9

France 134 (12) unknown

Germany 4,500 1,650

Hungary 45 (1) 2.0

Italy 401 (176) 74.0

Luxembourg 27 7.0

Netherlands 65 45.0

Portugal 71 50.0

Spain 23 26.0

Sweden 227 155

Switzerland 86 unknown

(UK) (37) unknown

Total (excl. AD for wwt) 5,740 2,195

Note: *Numbers in brackets show no of agricultural AD plants; remainder of plants are for wastewater treatment (wwt)


In total there are in the order of 5,800 AD plants in these 14 countries, with a design energy potential of around 2,200MW. These data include all AD plants independent of their capacity, feedstock, or design energy production. With 4,500 AD plants installed and operated by the end of 2009 Germany is by far the greatest European utiliser of this technology, followed by Austria (295), Italy (235) and Sweden (227). Some of the smaller countries, such as Belgium and Luxembourg, are also very active in energy production from biowaste. However, their strategy focuses on larger AD plants, e.g. by operating centralised plants, rather than targeting farm-scale projects. The findings of this literature review with regards to each key country‟s policy background and their actual AD market situation are described in Section 5. Whilst public institutions were able to provide national statistics on the overall number of AD plants and the associated energy production in the country, in most cases they were not able to provide details on individual plant locations or performances due to national data protection legislation. Supporting information on small-scale AD plants, their feedstock, and subsequently their performance was therefore extended to in-house databases held on operational AD plants, by SLR, LRS and Defra and via direct communications with key AD technology vendors. In total 862 AD plants were identified for which, as a minimum, the feedstock and/or the installed CHP engine size was available. The collated data for each country are included as Appendix B. Of the 862 plants identified, many did not provide the necessary minimum data required for further evaluation. For the next stage a further filter was therefore applied, only taking those plants forward where, as a minimum, the feedstock, the installed CHP engine size, and the operator or the designer/ technology vendor were known. As a result, 221 AD plants were taken forward into the subsequent plant scoring stage.

4.3 Representative Sample Selection

The key aim of this task was to develop a representative sample of relevant plants, from the 221 plants identified in the previous task that can be used as the basis for the plant site visit selection. A scoring matrix was developed scoring each plant against a series of key performance indicators. According to the total score the plants were then ranked and the around 60 highest scoring plants were taken forward for detailed data analysis. The scoring system is outlined in the following sub-sections; the scoring matrix and the results are included as Appendix C.

4.3.1 Screening criteria

A scoring matrix was developed comprising key performance indicators (KPI) in order to incorporate Defra‟s specific objectives of a) identifying relevant plants that deal with the specified waste and b) analysing the relationship between feedstock quantity and quality and biogas/ energy production. Other objectives included the identification of operational problems experienced and the handling of emissions. Following key performance indicators were used to account for these objectives:

o Data availability o Feedstock o Type of AD system o Plant performance


o Energy utilisation o Other technical considerations o Emissions

For each KPI a specific point scoring system was developed to account for the quality and quantity of data available. The scoring systems applied to the KPIs „feedstock‟ and „energy utilisation‟ are shown in Table 4-3, the scoring systems for all key performance indicators are summarised in Appendix D.

Table 4-3 Scoring systems for KPIs ‘feedstock’ and ‘energy utilisation’

Scoring parameter Score

Feedstock

a) no feedstock details available 0

b) feedstock not on Defra list (e.g. not manure, slurry, green waste, food waste, paper & card) 1

c) mix of feedstocks partly matching Defra list 2

d) mono- or mix of feedstocks matching Defra list 3

e) mono-or mix of feedstocks matching Defra list, including tonnage details 4

Energy Data

a) no energy output details available 0

b) only CHP engine size available 1

c) details on electricity produced available 2

d) data under c plus details on heat production and heat use available 3

e) data under c+d plus details on parasitic plant requirements 4

A weighting factor was applied to each KPI score, taking account of the relevance of each KPI with regards to meeting the project objectives. Within the remit of this study the plant feedstock and the available energy data were considered to have the highest importance amongst all key performance indicators, hence the score of these two KPIs was factored by two. Other objectives of this study were c) to investigate the relationship between biogas production and AD systems and d) to determine the relationship between the size of the plant and emission levels. Information on „plant performance‟, „data availability‟ and „emissions‟ was therefore weighted with a multiplier of „1‟. In order to get a comprehensive overview of the plant operations other technical considerations, such as operational issues or digestate end-use and trends in AD technology systems, were also investigated. Albeit of interest, these KPIs contribute to a lesser extent to key objectives of this study; they were therefore weighted with a factor of 0.5.

4.3.2 Selection of representative sample

According to the total score, the AD plants were ranked for each individual KPI, but also for the overall performance across all KPIs once the weighting factors had been applied. The top 50-60 overall highest scoring plants were taken forward into the next stage in which


detailed plant appraisals were carried out on the participating plants. Of particular interest to this study are a) the feedstock treated and b) the energy produced using this feedstock. However, some top ranking AD plants in these particular KPIs may not initially appear in the overall top 50 list, due to the lack of data in other areas. The top 50 list was therefore compared to the top ranking list of these two KPIs and missing top scoring plants were added to the final representative list. The results of the scoring exercise are discussed in detail in Section 6; the scoring matrix is included as Appendix C.

4.4 Site visit preparation

In preparation of the subsequent site visits the data of the shortlisted plants were analysed for their suitability to produce results that would be most valuable to the specific objectives of this study. Data gaps were identified and plant operators contacted for collation of the missing information, but also to confirm their willingness for a potential site visit.

4.4.1 Detailed data gathering

Data gathered during the desktop study generally provided information on the plant size, the technology supplier, the start of operation and the plant feedstock. More detailed data were required in order to evaluate the relationship between the feedstock and the amount of energy produced and the impact of changes in the feedstock or in the plant operation on the biogas/ energy production. A questionnaire in form of a site visit protocol was prepared, split into following sections:

o Feedstock(s): Identifying types and tonnages, required farmland, and no of animals;

o AD system: Digester size and type, no of tanks, and volume of gas storage;

o Technical data: Incl. feedstock(s) dry solids and volatile solids contents, digestate production and end-use, operational temperature, residence time, organic load, and pasteurisation (if applicable);

o Biogas production: amount of biogas produced, methane content, type, no and size of CHP engine(s), and CHP utilisation;

o Electricity/ heat production: Average electrical efficiency, parasitic electrical/ heat requirements, use of surplus electricity/heat;

o Other information: Environmental permitting route, emission control, experienced operational issues, any granted subsidies, plant Capex/ Opex.

A template of the site visit protocol is included as Appendix E. Once the contact details of the top ranking plants had been established, the plant operators or the technology vendors were contacted to confirm whether they would be willing to participate in this study. A site visit protocol was sent to each participating party. The returned questionnaires were evaluated together with information received via the phone directly and were used to select a total of 12-16 plants for a subsequent site visit. The data gathered during this stage are presented and discussed in Section 6.


4.4.2 Site visit selection

The collated data were split into three different categories, as follows:

By feedstock type: including plants that operate predominantly on the individual feedstock types targeted by the study, e.g. animal manure & slurry, food and garden/ plant waste, paper& card;

By AD type: different types of AD, e.g. mesophillic / thermophillic, high solids / low solids, single-stage / two-stage, batch / continuous;

By plant longevity / robustness: including plants that have operated successfully over a long period without any apparent process problems.

The aim was to visit a representative cross-section of plant types in order to highlight any performance differences associated with the chosen AD system choice or with the feedstock. To confirm the site visits, plant operators and/or technology vendors were contacted again in order to arrange the details for subsequent site visit(s). The results of the site visits are presented in Section 7; the key findings are discussed in Section 8.


5.0 REVIEW OF FARM/SMALL SCALE AD SECTOR – BY COUNTRY

5.1 AD development in key European countries

The total biogas production in the 27 European member states in 2008 (refer Table 4-1) was 7,542 kilo tonnes raw oil equivalent (ktOE), which equals around 87TWh of energy from biogas. This is an increase of 44% from 2005. Initial research (refer Section 4.1) showed that there are 14 European member states, in which small or farm-scale anaerobic digestion with energy generation is carried out on a medium to significant scale. The remaining member states source their biogas predominantly from landfill gas and sewage sludge. The implementation and growth rate of AD technology in EU member states that were identified to utilise biogas from decentralised agricultural plants, municipal solid waste plants and combined heat and power (CHP) plants, and thus were included in this research, is considerably varied. While some states have experienced a large increase in the number of new plants in recent years (e.g. Germany, Austria, and Denmark), others (like the UK and France) still lag behind. One reason for the different progress made in the various countries appears to be the variation in governmental incentives introduced by the respective governments in response to the targets set out in the European Commission White Paper on Renewable Energy23, which requires the use of 20% of renewable energy by 2020 and a cut in carbon dioxide emissions by 2050 of up to 60%. The following section gives a brief overview on the development of AD technology use in the identified key European countries.

5.2 Current situation in identified countries

5.2.1 Austria

Background In the early 1970s and 1980s installations of agricultural anaerobic digestion plants rose briefly due to the two worldwide oil crises and the resulting sharp increase in energy prices. However, the growth was short lived and it was not until 2002 when Austria experienced a significant increase in AD plants. Reason for the sudden increase was the newly introduced Green Energy Act, which subsidises the use of energy crops, enabling farmers to increase the gas yields and to make an income from the paid allowances. The new law also led to an increase of the average energy capacity installed, increasing from 30kWel on average to 250kWel on average. The total net energy installed rose from 12MWel in 2003 to 28.4MWel in 2004 and 71MWel by 200524. Figure 5-1 depicts the impact of the green energy act on AD plant installations for energy recovery.

23

European Union Directive 2003/30/EC 24

http://www.energytech.at/biogas/portrait_artikel-1.de.html


Figure 5-1

Development of registered AD plants for the production of renewable energy [MWel] Source: [E-Control, Statistik Austria, 2007]

The feed-in tariff depends on a) the installed net energy output and b) on the waste feedstock. AD plants that accept feedstock other than the classified agricultural wastes are classed as co-fermentation plants; the feed-in tariff for co-fermentation plants is reduced by 25% as is shown in Table 5-1. Agricultural wastes include manures, slurries, food and plant wastes, animal feed, brewery water, dairy wastes and silages amongst others, but exclude e.g. abattoir wastes and sewage sludge. The latter is banned as feedstock for these plants altogether.

Table 5-1 Austrian feed-in tariffs as per Green Energy Act 2002 (BGBl II Nr. 508/2002)10

Without co-fermentation

With co-fermentation

In Cent/kWh (p/kWh)25

In Cent/kWh (p/kWh)

AD plants up to 100 kWel 16,50 (14.85) 12,38 (11.14)

AD plants over 100 up to 500 kWel 14,50 (13.05) 10,88 (9.79)

AD plants over 500 up to 1000 kWel 12,50 (11.25) 9,38 (8.44)

AD plants over 1000 kWel 10,30 (9.27) 7,73 (6.96)

The payment of the tariffs shown is guaranteed for a period of 13 years. AD utilisation in Austria to date By the end of 2009 there were 295 AD plants registered with a total energy generation of 77.2MWel installed. This is around 570GWh or 1% of the overall power consumption in Austria. According to research carried out in Lower Austria26 81% of the plants export the produced heat for external use.

25 Based on 1€ = £0.9

26 www.biogas.klimaaktiv.at

Re

ne

wa

ble

ele

ctr

icit

y p

rod

uc

tio

n f

rom

AD

(M

Wel)


As a result of the definition of agricultural waste (renewable resources, also called NaWaRo in Austria and Germany) and its tariff classification over 90% of the plants installed after 2003 are without co-fermentation. Figure 5-2 shows the percentage contribution of the treated waste feedstocks in Lower Austria. For the production of 77.2MWel arable land of c. 25,000ha is required; this is around 1.8% of the available agricultural land in Austria.

Grass

Mix/Sunflower

Seeds, 7%

Potato Water, 2%

Sunflower Silage,

3%

Biowaste, 4%

Corn Cob Mix, 4%

Sudan Grass, 3%

Grass Silage, 8%

Rye Silage, 7%

Chicken Manure,

1%

Pig Manure, 1%

Cow Manure, 2%

Pig Slurry, 3%

Cereal Residues,

Horse Manure,

Cereals, 2%

Cow Slurry, 1%

Figure 5-2

Waste feedstock treated in AD plants in Lower Austria12

This percentage distribution of waste feedstocks shows how popular energy crops have become, since introduction of the Green Energy Act. More than half (52%) of the waste feedstock is maize silage („Maissilage‟). Altogether 77% of the waste feedstock originates from energy crops. The treatment of manures („mist‟) and slurries („guelle‟) contributes only 10% of the total waste treated by AD and the remaining 13% are food waste and animal feed.

5.2.2 Belgium

Background Belgium consists of 2 main regions: Flanders and Wallonia. Both regions utilise large for agriculture, with an estimated available energy potential of 975ktoe (MW) from organic sources, including agriculture, forestry and municipal organic waste27. However until the European Landfill Directive was enforced in 1999 there was little activity of the AD sector. The implementation of the Landfill Directive led to a reduction in municipal waste landfill from 34% in 1999 to 23% in 2005. A number of new AD installations were constructed to treat some of the diverted organic waste. The trend towards AD treatment increased further due to the introduction of the European Renewable Energy Directive. The current feed-in tariff for the co-generation of electricity and heat produced from AD is 9€c/kWh (8.1p) and a further increase of this bonus is currently being discussed. The bonus

27

Agrobiogas, 2006: Deliverable 1: Update on the ongoing AD research activities and results


for the sole use of thermal energy is substantially less, although the exact value is unknown. Additionally digesters, CHP engines and biogas storage tanks are eligible for a grant of 15% of the capital investment costs28. AD utilisation in Belgium to date By 2008 Belgium produced around 45MW of renewable energy from around 40 anaerobic digestion plants, including sewage sludge treatment plants. With 30 plants most of the AD treatment plants are located in the Flanders region in, only 4 are known to be in the region. The 30 plants in Flanders produced a total of 55MW of electricity in 2009. Due to its widely spread population and the extensive agricultural structure, Belgium preferably targets large AD installations; the average AD plant size is 1.5MW. These plants are often owned by a farmer‟s co-operative and the government aims to provide the local communities with the produced heat via a district heating network in the future. Small AD plants are seen to be less beneficial for maximum energy utilisation due to the lack of available heat users.

5.2.3 Czech Republic

Background The first biogas plants in the Czech Republic were constructed in the 1960‟s. The initial biogas developments were waste water treatment plants and agricultural biogas plants. During the 20th century the agricultural plants were installed as manure processing services at large centralised pig, cattle or diary production facilities, where the biogas was used mainly in process heating or space heating (in pig farms). Only a small fraction was used in CHP. The second historical development milestone was set up by new Renewable Energy Act (REA 180/2005 Sb.) in 2005. The REA supports renewable energy utilisation in order to fulfil all the national and European targets. The Czech legislation supports production and utilization of agricultural biogas, sewage gas and landfill gas. Biogas development in the Czech Republic stems from the REA and is achieved by a) priority grid connection, b) fixed grid connection fees, based on the installed power, and c) „feed-in tariffs‟ and „green bonuses‟. Green bonuses allow investors to sell electricity on the market and motivate them to actively trade their product. The level of the tariffs and bonuses is annually updated by the Energy Regulatory Office, the control authority of the entire energy grids sector. The support currently includes only the electricity production29. AD utilisation in the Czech Republic to date Agricultural biogas production and utilisation started in early 2007, when the first „classical‟ agricultural plants were built, which involved the utilisation of dedicated biomass production with the addition of manure. Nearly 40 agricultural biogas plants have been constructed annually since 2008. By January 2010, there were 91 farm scale biogas plants with a combined power output of 54MWel. The development of AD biogas plants in the Czech Republic is shown in Figure 5-3.

28 Claudius da Costa Gomez et al, 2004: European Biogas Conference, Northern Ireland: Current

Practice and Progress in the adoption of anaerobic digestion in the European Union 29 Source Czech Biogas Association


Figure 5-3

Farm-scale and Waste Water Treatment Plants Biogas Plants and Installed Power

The total estimated biogas potential from agriculture in the Czech Republic is 500MW per year. The projected power production until 2020 is illustrated in Figure 5-4.

Figure 5-4

Estimated Agricultural Biogas to 2020

5.2.4 Denmark

Background Like Germany and Sweden, Denmark began to develop alternative energy sources as a result of the oil crisis in the 1970‟s and has over 25 years experience in this proven technology. A development programme for farm biogas plants and preliminary joint biogas

Nu

mb

er

of

AD

in

sta

lla

tio

ns

In

sta

lled

po

we

r (MW

el)


plant projects was initiated, with the first farm plants being built in 1975, and the first joint plant in 1984. Their finances were solely based on energy sales. However, fossil fuel prices fell and biogas production had to be increased through the use of organic industrial waste in order to maintain profitability. This concept proved successful and was subsequently implemented by all the Danish biogas plants. In the mid 1980s farmers were required to store liquid manure, initially for 6 months, then for 9 months, and limits were imposed on the amount of liquid manure that could be spread per unit area of land. This requirement and governmental incentives on planning permissions for new storage facilities in conjunction with biogas plants led to the installation of a number of new plants AD plants. In the early 1990s two tendencies appeared: the construction of very large plants, and the construction of plants built to meet the heat requirements of small rural communities. During this time efforts also continued to standardise and modularise biogas plants, resulting in cheaper, simpler units. Apart from three municipally-owned joint biogas plants, all plants are exclusively or jointly owned by the farmers involved30. Denmark has recently introduced new rules for subsidies with 0.745 dkk/kWh for electricity produced from biogas. The aim of the subsidies is to facilitate for production of new plants and for rebuilding of old plants to increase their capacity. The goal is to have a production of 2.8 TWh by 2020, which means 4 new plants per year until then. The biogas potential in Denmark has been estimated to around 11 TWh which is 5% of the total energy consumption in the country. This can be compared to the production during 2004 which was around 1 TWh31. Linked to the energy targets is the environmental goal of Danish farmers to have 50% of manure being utilised in anaerobic digestion plants. In Denmark biogas is produced to a cost of 3 dkk/Nm3 (£0.34 /Nm3) to be compared with a price on natural gas of 2 dkk/Nm3 (£0.23 /Nm3).The produced biogas can be transported in a pipeline to the nearest CHP (Combined Heat and Power plant) to a cost of 0.1 dkk/Nm3

(£0.011 /Nm3), or it can be upgraded to an estimated cost of 1.5 dkk/Nm3 (£0.17/Nm3). Since Denmark has coal fired CHPs it has been prioritised to replace some of the coal rather than upgrade biogas and use it as a vehicle fuel and replace petrol, however two upgrading plants are in the planning process. This differs to Sweden where no coal fired CHPs exist and the biggest environmental benefit is therefore gained by upgrading biogas and replacing fossil transport fuels. The figure below demonstrates the costs for natural gas, biogas, and upgrading per Nm3.

30 Source www.biogas.dk

31 Source- Annelli Persson, Swedish Gas Centre


Figure 5-5

Cost in Danish crowns per Nm3 for natural gas, biogas, and transport by pipeline heat and power production plant, and biogas & upgrading cost32.

The following are incentives for biogas plant development in Denmark:

Socio-economic benefits of biogas production

Fulfillment of environmental policies - cheap tool for reduction of GHG emissions (5.37 Euro/ton CO2 equivalent) - 90 kg CO2 EQ/t biomass treated

Agricultural benefits include: - cheap slurry storage - less transport - less odours and flies - less CH4 emissions from storage and spreading - cheap redistribution of slurry (centralised co-digestion) - sanitation and pathogens control - NPK declaration of digestate - high N-utilisation and less N-leaching in digestate - possibility of fibre separation

In Denmark there are no standard increased feed-in tariffs available for decentralised CHP plants based on biomass combustion built after 2002. Existing CHP plants built before 2002 receive an increased feed-in tariff consisting of different components. AD utilisation in Denmark to date Figure 5-6 illustrates the location of all the existing centralised and farm-scale biogas plants in Denmark to date as well as identifying the new biogas plant projects which are in the pipeline.

32 Anneli Petersson, 2008: Biogas from an international Perspective; Swedish gas Centre

Co

st

in D

an

ish

Cro

wn

s/

Nm

3 b

iog

as

A:

Natural Gas

B:

Biogas

C:

Heat transport by pipeline


Source: University of Southern Denmark

Figure 5-6

Biogas plants in Denmark (2009)

There are currently 60 farm-scale AD plants operating in Denmark treating approximately 2.14 million tonnes of animal slurry (5% of the total produced) and 0.4 million tonnes of organic waste. The energy production in 2009 was 0,91PJ. All AD plants in Denmark use a wet stage process with either 1 or 2 stages. There is not a preference for either mesophillic or thermophillic systems with both temperature processes being utilised.

The existing framework for Biogas in Denmark includes the following:

The current price of sold m3 CH4 is 0.4 Euro

Heat production is exempted from energy and CO2 taxation

Power production has a price guarantee of 0.08 Euro/kWh for the next 10 years until 2019 and of 0.053 Euro/kWh for the following 10 years (for plants established before 2007)

5.2.5 France

Background The first agricultural AD plants in France were built in 1979 in response to a national development programme. However, of the 95 plants constructed only five were still in operation by 2000. The reasons for this decline were put down to design inefficiencies but also to the lack of use of the produced biogas due to the falling energy prices. In 2000 the French government included the utilisation of biogas from agricultural AD in its action programme to tackle greenhouse gases. AD utilisation in France to date Despite being one of Europe‟s large biogas producers, France only utilises a very small amount of its resources by AD. In 2009 there were only 12 AD plants registered for the use

Note: Red circle is centralised

Blue circle is farm scale Outline box is new biogas


of organic wastes. The remaining 140 digesters are used for wastewater treatment or industrial effluent treatment.

5.2.6 Germany

Background The adoption of the first Renewable Energy Act (EEG) in March 2000 led to sharp increase in AD plant installations In Germany. In 1990 there were only around 100 agricultural AD plants in Germany recorded and the uptake of new plants continued to be slow up to the introduction of the EEG33. The EEG increased the already available nominal incentive for feed-in tariffs, but for the first time also guaranteed the payment of feed-in tariffs for a period of 20 years, which enabled long-term investment and planning security for the biogas production from anaerobic digestion plants. As a result the number of AD plants rose to over 2,000 by the year 2003. At the same time the average tonnage treated per plant increased simultaneously, partly due to the treatment requirement of organic municipal wastes, introduced in 1994. After experiencing a sharp decline in new AD installations in 2003 due to ceased subsidies the EEG was amended in 2004. The current Renewable Energy Act guarantees feed-in tariffs for 20 years; Table 5-2 shows the current feed-in tariffs for renewable energy from CHP engines, split into 3 categories.

Table 5-2 Feed-in tariff Germany for renewable energy from AD via CHP

Electricity from renewable energy crops as per Renewable Energy Act 2004 (EEG)

Feed-in tariff (ct)

Feed-in

tariff (p)34

Baseline tariff <150kWel 11.67 ct. 10.50

Baseline tariff 150-500kWel 9.18 ct. 8.26

Baseline tariff 500kWel -5MWel 8.25 ct. 7.43

Energy crop-tariff for the treatment of renewable energy crops 06,00 ct. 5.4

CHP-tariff (only, if heat is used) 02,00 ct. 1.8

Feed-in tariff per kWh electricity for Installations from 2009: 16.25 -19.67ct.

14.63 – 17.70

In addition to the EEG the electricity production from biomass is also regulated by Biomass Ordinance from 2001. The Biomass Ordinance defines acceptable feedstocks and technologies that may be used for the energy generation. It also regulates the associated environmental obligations. AD plants treating waste as classified in the Recycling Management and Waste Regulations (1994) require an environmental pollution prevention control permit, if the waste throughput exceeds 10t/d and/ or if the installed CHP engine size is >1MW. AD utilisation in Germany to date Since the enforcement of the amended renewable energy act in 2004, the number of AD plants in Germany has more than doubled and by the end of 2009 around 4,500 AD plants

33 W. Bischofsberger, et al, 2007: Anaerobtechnik

34 Based on 1 Euro = £0.9


were installed. Due to the amended EEG many co-fermentation plants have changed their feedstock to energy crops and it is estimated that over 80% of all biogas plants are operated fully or at least partially on energy crops35. Most plants transfer the produced electricity into the local electricity grid to get the maximum benefit from the feed-in tariffs. It was also reported that 74% of the produced heat are exported for external use. Although new AD installations have lessened in the last 2-3 years, the installed CHP electricity capacity has continuously risen, suggesting that plants have been extended in favour of installing new AD plants. The percentage distribution of AD plants in Bavaria36 according to the power installed as per EEG classification is shown in Figure 5-7. Here, the installed average electrical capacity has increased from 182kW in 2005 to 196kW in 2006.

Figure 5-7 Percentage distribution of CHP electricity installed at AD plants

The current trend shows that the interest in agricultural AD treatment has increased significantly since the renewable energy act and the associated feed-in tariffs came into force. The market is currently said to be most active in the 180-250kW plant range, which is most likely the result of the high feed-in tariffs.

5.2.7 Hungary

Background There is currently a push in the Hungarian energy sector to move from coal and fuel oil dependent generation to natural gas. Hungary is a signatory to the Kyoto Protocol, and they have implemented the climate change legislation required by EU law. In Hungary natural gas has the biggest share in the energy consumption mix (44%) and approximately 80% is imported, therefore substitution of natural gas by domestically produced biogas has become a particularly pressing issue. The Hungarian National Renewable Energy Strategy (RES) therefore places special emphasis on promoting biogas production and use (ITD, 2008). The Hungarian government has tried to encourage the use of currently available bioenergy by setting blending targets, guaranteeing feed-in prices and other support programs among

35 Landwirtschaftskammer NRW, 2009: Biogas in Nordrhein Westfalen

36 Bayrische Landesanstalt fuer Landwirtschaft, 2006: Biogasanlagen in Bayern


which is the guaranteed purchase price for electricity from renewable energy sources (feed-in tariff). Biogas is expected to grow in importance in the coming years in Hungary. In 2005 only 10% of the potential for biogas was used, large-scale supply of feedstocks such as liquid manure, sewage sludge, and slaughterhouse waste provide opportunities for the further development of Biogas. In 2006 electricity production from biogas accounted for 0.08%. The main resources for biogas are liquid manure (14-15 million tpa), slaughterhouse waste (300,000 tpa) and sewage sludge. The Hungarian legal framework for promoting biogas production consists mainly of the Act No CX (2001) on Electricity, its Amendment (Act No LXXIX, 2005) and associated Governmental Decrees of Execution (180/2002 [VIII.23] and 389/2007). The non-central-budget-based feed-in tariff scheme, introduced in September 2005, is guaranteed until 2020 (Renewable Development Initiative, 2009)37. The system was modified in favour of smaller plants and those providing remote heating in 2008. According to this Regulation, electricity suppliers are obliged to purchase electricity from energy producers that utilise renewable energy sources if their capacity is over 100 kW. Currently in 2009, a biogas producer receives, on average, the average feed-in price for electricity from biogas, approx. 18.35 HUF (0.073 Euro) per kW. The following table provides an overview of the Hungarian feed-in tariff scheme.

Table 5-3 Hungarian feed-in tariff scheme

Source: ITD Hungary (2009) and Hungarian Energy Office (2009).

Note: *Converted by using the exchange rate 1 EUR = 300 HUF.

Unlike the German support scheme, the Hungarian scheme does not provide additional premiums or technology specific payments, but differentiates the payments depending on the season and daytime (i.e. peak rates)38 The following financial incentives are earmarked to support investments in the renewable energy sector in Hungary:

Subsidy I – EU funds for renewable energy sources in Hungary, the operational program “Environment & Energy” a sub-program which allocates grants (EUR 280 million) for investments in systems that generate electricity from renewable energy. The grants cover 10-60% of eligible costs for heat and electricity production from renewable sources.

37 The Electricity Act considers the feed-in tariffs to be an intermediate solution which should lead to a green certificate system. 38

The fact that this tariff system is based on the tariff calculation for conventional electric power plants (daily load in summer and winter, i.e. peak/valley rates) highlights the evidence that the most biogas plants operate on an industrial scale.


Subsidy II National Energy Saving Plan – this program promotes the use of renewable energy sources through subsidies for clean energy efficiency for households with lesser amounts

Loans (Energy Saving Credit Program 2008) – loans subsidise the use of renewable energy sources through low-interest loans and may be used jointly with subsidies awarded by the NEP or independently.

Taking into account feed-in tariffs and subsidies, Hungarian biogas producers receive a total 11.5-12.9 Ct per kWh (Neue Energie, 2009), which is comparable with payments for German biogas producers only if the basic tariff and the CHP bonus are paid39 The Hungarian biogas energy support strategy suggests that the reduction of the import dependency on natural gas has the top priority in promoting biogas production. Although nearly 90% of Hungarian agricultural holdings have a size of less than 5 hectares, biogas production on a very small farm scale is economically not feasible and thus is not in focus of the tariff scheme. The high grants, covering up to 60% of eligible investment costs in Hungary, benefit investments in large scale biogas units. Therefore supporting primarily large scale biogas production on an industrial scale in order to increase the share of domestic energy supply is the main motivation behind the Hungarian support system. Large industrial biogas plants ranging into the megawatt-scale dominate in Hungary, while e.g. in Germany, farm-scale biogas units continue to prevail. AD utilisation in Hungary to date The current total biogas production in Hungary is equivalent to 20 kilotonne of oil equivalent (ktoe), and Hungary ranks at no‟16 in the EU27. Currently only 10% of the feasible biogas potential is used. A large proportion (60%) of land use in Hungary is arable agriculture so therefore the country has many opportunities to extend the biogas production. The annually accrued amount of manure and slaughterhouse waste, which can be used as input for biogas production, amounts to 15 Mio m3 and up to 300,000 tonnes which also provides opportunity for the further development of biogas production. In 2008 there were 45 biogas plants in Hungary. The first biogas plant that used agricultural crops and manure as input factors was put into operation in 2003 in Nyírbátor. With its production capacity of 2.5 MW (Neue Energie, 2008) it was the largest biogas plant in the world. In 2007 there were 6 farm-scale biogas plants using agricultural feedstock as input material. In contrast to German agricultural biogas plants, Hungarian agricultural biogas is based mainly on agricultural waste, by-products and residues, and not on energy crops. The table below shows the number of current biogas plants and planned extension to 2015.

39 In both countries, biogas producers also have the possibility of generating additional income from

the sale of Green Certificates


Table 5-4 Present and planned biogas capacities in Hungary from 2007

Source ITD 2008

The fast development in biogas production is due to the last amendment of the Hungarian Act on Electricity in 2007, which puts more emphasis on the promotion of farm-scale biogas plants. According to the ITD Hungary, a further 38 biogas plants of agricultural type are currently planned or already under construction. Significant EU grants, national subsidies and loans are available that support the establishment of small farm-scale plants with a capacity of 250-500 kW each (ITD Hungary, 2009 and BMUNR, 2009)40.

5.2.8 Italy

Background In order to promote Renewable Energy Systems (RES), Italy has adopted the following schemes:

Priority access to the grid system is granted to electricity from RES and CHP plants;

An obligation for electricity generators to feed a given proportion of RES-E into the power system. In 2006, the target percentage was 3.05% and an annual increase equal to 0.75% for the years 2007 to 2012 was subsequently introduced. Therefore the rate of the “minimum obligation quota” will be: 3.80% in 2007; 4.55% in 2008; 5.30% in 2009; 6.05% in 2010 and 6.80% in 2011. In case of non-compliance, sanctions are foreseen, but enforcement in practice is considered difficult because of ambiguities in the legislation;

Incentive schemes such as the Tradable Green Certificates, Sole Tariff and Exchange on Site for the production of renewable energy (see below).

Electricity produced from biogas plants that started operation after 31 December 2007 are entitled to either the incentive mechanism of the Sole Tariff (Tariffa Onnicomprensiva) or, as an alternative, to Green Certificates. As an alternative to the Sole Tariff, but in combination with Green Certificates, biogas plants generating electricity or co-generating heat and electricity <200kW and that started operation after 31 December 2007 can request to benefit from the Exchange on Site (Scambio sul posto) scheme. Each incentive scheme is explained more in detail below:-

Green Certificates Green certificates, introduced in 2002, are awarded to producers of renewable electricity that began operations after 1st April 1999 and are a tradable commodity that can be used to fulfill

40 EU funds for renewable energy sources: KEOP 2009/4.4.0 (Heat and/or electricity production from

renewable sources) and KEOP 2009/4.2.0 (Local heat and cooling supply from renewable sources).


the RES-E obligation of energy generators. Green Certificates are available for biogas plants of any size and consist of a financial incentive for all the electricity produced, calculated by applying a technology coefficient (1.3 for agricultural biogas plants, which might potentially be increased to 1.8 depending on legislative clarifications that are currently pending) to the value of the certificate. The incentive is guaranteed for a period of 15 years, reduced to 12 years for plants that came into operation before 1st Jan 2008, however the technology coefficient can be reviewed by the government every 3 years. Whilst the value of Green Certificates is subject to free market trading, it is also subject to a rather rigid pricing structure as legislation approved in 2008 has established that they are placed on the market at a value equal to the difference between:

o the original reference value of 180€/MWh applied by the government when Green Certificates where first introduced; and

o the average market price of electricity for the previous year

For 2010, the reference price for Green Certificates as indicated by the government is 112.82 €/MWh.

Sole tariff (Feed-in Tariff) The sole tariff, similar to the green certificates, provides a financial incentive to producers of renewable electricity connected to the national grid, but also applies to biogas plants <1MW and started operations after 31st December 2007. The value of the sole tariff varies depending on the technology used. For biogas facilities it is fixed at 0.28 €/kWh. The incentive is guaranteed for a period of 15 years although the value of the incentive can be reviewed by the government every three years.

The Exchange on Site scheme Biogas plants up to 200kW (co-generation and electricity only) may request, as an alternative to the Sole Tariff, to benefit from the Exchange on Site scheme. The Exchange on Site consists of implementing a particular form of in-situ consumption scheme allowing for the electricity produced and fed to the grid to be utilised at a different time from when it is produced. This means, for example, that a facility feeding more electricity into the grid in excess of its parasitic requirements over a given year can bank and use this „electricity credit‟ over the following years. Whilst the Exchange on Site is not compatible with the Sole Tariff, it can be utilised in conjunction with the Green Certificates.

AD utilisation in Italy to date Since the introduction of the Sole Tariff and the implementation of the changes to the Green certificates from 1st January 2008, the development of agricultural AD plants in Italy has increased significantly. 176 AD plants were in operation in 2009 with a further 59 being under construction compared to the 120 operating plants and 30 plants under construction in 200741. Due to the favourable financial conditions created by the Sole Tariff and Green Certificates, this trend is expected to continue in future years. Almost 90% of these plants are located in the north of Italy and approximately 50% use a mixed feedstock of slurry, energy crops and other agricultural residues, which reflects the combination of intensive cattle breeding and a limited number of crops such as maize, sugar beets and soybeans typical of farms in northern Italy.

41 Sergio Piccinini, „Biogas: Situazione e Prospettive‟, CRPA, Verona Bioenergy EXPO, Feb 2010.


In addition to agricultural AD plants, another 166 AD plants exist in Italy processing other feedstock such as sewage sludge and the organic fraction of MSW, bringing the total of AD plants to 401 (of which 61 are under construction) for 2009 generating a total of 345 MWe installed as of 30 June 2009. Most plants transfer the produced electricity into the local electricity grid to receive the maximum benefit from the Sole Tariff and Green Certificates; however, the use of heat for external use is minimal. Currently there are no plans in Italy to introduce incentives for the use of the heat.

5.2.9 Luxembourg

Background Luxembourg is almost totally dependant on energy imports. Oil is the primary energy fuel and natural gas which is gradually replacing the solid fuel consumption. The majority of energy imports are of oil and natural gas, with the latter contributing substantially to the electricity generation since 2002. The share of transport in total final energy consumption is around double that of the EU-27 average. Energy consumption and CO2 emissions per capita are the highest in the EU-27. While the electricity production from small-scale hydro power has stabilised in recent years, the contributions from onshore wind, PV, and biogas have now started to increase. The 1993 Framework Law defines the renewable electricity (RES-E) policy: feed-in tariffs are given to different types of RES-electricity technologies (namely, all renewable energy sources technologies, but geothermal). These tariffs were amended in February 2008. The new tariffs are in force for installations starting after the first January 2008. Tariffs are guaranteed over 15 years with simpler administrative procedures. They are differentiated according to technology and capacity. Some tariffs are degressive. Biogas feed-in tariffs amount to 150 euros per MWh for small systems (0 to 150kW), to 140 euros (151-300kW), to 130 euros (301- 500kW) and 120 euros (501 kW-2500kW). Subsidies are also available to private companies (Framework Law of Economy Ministry- Framework Law of the Ministry of Middle Classes), communes (Environment Protection Fund of the Environment Ministry), farmers (Law from the Agriculture Ministry supporting rural development) and households (regulation of the 21st December 2007 of the Environment Ministry) investing in RES-E technologies. In January 2008, new grants for households entered into force to promote RES electricity with the investment aid for biogas installation amounting to 50%. Since January 2008, a so-called “heat premium” (prime de chaleur) has been introduced. This premium differs according to technologies (solid biomass, biogas and waste wood) and is granted for each MWth commercialised. For biogas, waste wood and solid biomass, the producer gets 30 euros per MWh if certain conditions are fulfilled. The new tariffs can apply to existing biogas installation (existing before the 1st January 2008) in case of extension of capacity. Source Renewable Energy Policy Review Luxembourg, EREC March 2009 AD utilisation in Luxembourg to date In 2007, electricity production from biogas amounted to 36.6GWh, solid municipal waste to 24.3GWh, small hydro 111.3GWh and wind to 64GWh. Taking into account of the size of the country Luxembourg has already 27 biogas plants, although most of Luxembourg‟s biogas production comes from urban wastewater treatment plants. There are a number of farm-


related digesters installed. A ministerial regulation, passed in 1994 allows for the support of renewable energy projects including biogas. This measure has however chiefly benefited hydroelectric, wind energy and photovoltaic projects.

5.2.10 Netherlands

Background While the use of anaerobic digestion treatment for industrial effluent is well developed in the Netherlands, biogas from agricultural biomass is limited. In the 1980s more than 30 farm-scale plants were built but high operational costs and low fertilizer value of the digested manure has meant that only a small number of these plants are still in operation. In the WFE-net Final report (2000) it was reported that “their total number does not exceed 15” A number of Centralised Anaerobic Digestion plants were also built, but were closed down due to financial reasons associated with expensive processing and transportation costs. In its climate policy, the Netherlands set a global target of 5% renewable energy by 2010, and 10% by 2020. According to the EU Directive, the RES-E share of the Netherlands should reach 9% of the gross electricity consumption in 2010. RES-E policy in the Netherlands is based on the 2003 MEP policy programme (Environmental Quality of Power Generation), and is composed of the following strands:

Source specific premium tariffs, paid for ten years on top of the market price. These tariffs were introduced in 2003 and are adjusted annually. Tradable certificates are used to claim the feed-in tariffs. The value of these certificates equals the level of the feed-in tariff. Due to budgetary reasons, most of the feed-in tariffs were set at zero in August 2006.

An energy tax exemption for RES-E was in place until 1 January 2005.

A Guarantee of Origin system was introduced, simply by renaming the former certificate system.

In the Netherlands, biofuels have traditionally been supported by means of R&D funds. To this date, technological innovations in this field are encouraged by means of financial support. In 2006, a tax relief system was introduced. The mechanism that was chosen links the quantity of biofuels to the national targets, by requiring of suppliers that regular fuels contain a 2% share of biofuel from 2007 onwards, and a 5.75% share from 2010 onwards. Limited investment subsidies are available for RES heating and cooling activities. Feed-in tariffs are also applied to CHP.

The Dutch ministry of economic affairs revealed its 2009 feed-in tariff scheme, setting a large, approximated 1000MW, cap for renewable energy sources, from which 830MW for onshore wind and also including mini-hydro in its regime. SDE is a feed-in (tariff) premium subsidy scheme which supports the production of renewable gas and electricity. The scheme will cover up to 1000MW, which is equal to an investment of approximately EUR 1.5 billion.

Subsidy rates for electricity generation from biomass will range from EUR 0.115 to EUR 0.177 per kWh, depending on technology. Anaerobic digestion will also be supported when biogas is fed into the natural gas grid. The tariff ranges between EUR 0.465 and EUR 0.583 per normal cubic meter if manure is co-digested. Between 16MW and 22MW will qualify for the latter tariff. The ministry will also give an incentive to biomass plants to use waste heat in a sustainable way, by implementing a 'commission' system. The more energy efficient a plant is, the higher the bonus under the tariff scheme.


AD utilisation in the Netherlands to date There are currently about 130 digestion projects in the Netherlands with an installed capacity of 130MWe. In 2009, 6 new Green Gas projects started with biogas upgrading and grid injection.

5.2.11 Portugal

Background Portugal is required to meet 31% of its gross electricity consumption by renewable electricity sources by 2010 but the government in consultation with other EU states has increased the target to 39%. This is dependant of establishing inter-connections with other Central European countries like Spain and France as Portugal cannot consume all its production. Consequently the renewable energy sector (especially wind and solar power) expanded rapidly. Last year (2009) the country produced 35.9% of its total electricity consumption from renewable sources. As a result Portugal is close to meeting its 2010 target; however the majority of the capacity is from hydro-electric power.

In order to promote Renewable Energy Systems (RES), Portugal has adopted the following schemes:

Fixed Feed-in tariffs per kWh for PV, wave energy, small hydro, wind power, forest biomass, urban waste and biogas.

Investment subsidies up to 40% (PRIME-Programme)

Tax reductions

Subsidy payments and tax incentives have been largely, though not entirely, used for smaller-scale renewable energy applications. Feed-in tariffs and tendering schemes are used principally for larger-scale renewable applications. The Decree-law 33_A of 16 February 2005 modified the system of feed-in tariffs, establishing a new calculation system. The formula for calculation of the feed in tariffs takes into account the technology, the environmental aspects and the inflation rate through the index of prices to the consumer. There are also some minimum and maximum tariffs, according to the variations of load on the grid. With regard to biogas, a feed-in tariff of 10.2€cents/kWh for a period of 15 years is available. Other incentives available include a reduced VAT rate of 12% for all RE equipments purchased within the national territory and a support level of 35% of the capital investment applicable only to SMEs to a maximum of 250,000€ per project. AD utilisation in Portugal to date In 2008 only 12.5MW of energy were generated from biogas installations (8.2 MW in 2006) in Portugal. The government‟s aim is to help the sector move towards a target of 100MW of installed capacity for anaerobic waste treatment units over the next few years42. There were 71 registered small scale farm-based Anaerobic Digestion installations in 2006, albeit using some rudimentary technologies. These were mainly used to supply local energy needs. However, the majority are no longer operational or their current situation is unknown due to lack of regulatory controls. Although hardly any information seems to be available, it is likely that about 80% of these plants are operated on animal manure. The current lack of

42 EREC, „Portugal: Renewable Energy Policy Review‟, 2009.


information may be due to Portuguese renewable policy focusing mainly at forestry biomass and biodiesel/bioethanol production as well. Figure 5.8 below shows the state of these installations, with only 48% that were functioning at the time but the greater number of them had fallen into various states of disrepair. 59% of the respondents of the survey could not quantify the amount of biogas produced.

48%

23%

29%

Operating AD Plants

Non Operating AD

Plants

Status unknow n

Figure 5-8 AD installations in Portugal

Since 2004 to date (February 2010)43, only 4 new organic waste treatment units were built in Portugal. The main barriers for growth cited include:

High investment and operational costs;

Local apathy in developing Centralised Systems;

Lack of regulatory controls and technical support and;

Current legislation does not provide sufficient fiscal incentives to generate „green electricity‟ and the main utility company EDP (Electricidade de Portugal) has a strong market monopoly.

However, further regulatory mechanisms like ENRRUBDA44, the national policy on reduction of BMW landfilling; have proposed ambitions organics processing targets as seen from Figure 5.9 below.

43 Presentation by Ana Silveira at International 8

th ASA Waste Days: MBT and anaerobic digestion in

Portugal 44

Estratégia Nacional para a Redução dos Resíduos Urbanos Biodegradáveis destinados aos Aterros


Figure 5-9 Projected biowaste diversion targets for Portugal

The main drivers for AD development will be the need to establish organic processing capacity for MSW in order to meet national targets rather than financial incentives for the development of renewable energy. The renewable energy targets are being met largely due to high capacity for hydro-electric power and wind power and therefore there financial stimulus to develop small scale AD plants do not exist. Portugal will need to divert 1,976 Ktpa of BMW by 2016 in order to meet targets set in ENRRUBDA. The current processing capacity is 153,000 tpa of source segregated organics collected through 545 composting plants and 2 AD plants; and 173,000 tpa through MBT plants. The known planned future capacity will be an additional 350,000 tpa through 3 MBT plants and 1 AD plants.

5.2.12 Spain

Background In addition to the European renewable energy targets Spain has the specified a target of generating 30% of its electricity from renewable electricity by 2010. In 2008, Spain was still far from reaching these targets, having produced 7.6% of renewable energy and 19.7% of renewable electricity respectively. Spain uses feed-in tariffs in order to encourage investment in renewable energy generation capacity. The main law is the Real Decreto 661/2007. The decree sets up financial incentives for biomass and biogas plants of up to 13.06€cents/kWh for the first 15 years, depending on size of the plant and feedstock/technology. The owner of the facilities may choose one of the following options:

1. Transfer electricity to the system through the grid, therefore being paid a feed-in tariff for it;

2. Sell the electricity on the wholesale electricity market. In this case, the electricity sale price will the sum of the actual wholesale market price and, if applicable, a premium

45 This includes the 1 plant in the Island of Madeira off the west coast of Africa.

http://en.wikipedia.org/wiki/Spain


price (see below). In this latter case, a higher and a lower limit (cap and floor) applies to certain technologies.

The titleholders of the facilities may choose the most suitable sale options for minimum periods of one year. Should they choose to sell the electricity on the wholesale market, the premium to be paid every hour is calculated as follows:

a) For values of the market price plus the reference premium that are lower or equal to the lower limit, the premium value to be paid shall be the difference between the lower limit and the daily market hourly price at that time.

b) For the market price values plus the reference premium included between the upper and the lower limits, established for a given group or subgroup, the value to be paid shall be the reference premium for this group or subgroup, at that time.

c) For values of the market price between the upper limit and the upper limit minus the premium price, the value of the premium to be paid shall be the difference between the upper limit and the market price at that time.

d) For the market price values higher or equal to the upper limit, the price of the premium to be paid shall be zero.

The average market price of electricity for 2007, 2008 and 2009 was 4.2 €cents/kWh, 6.4€cents/kWh and 3.7€cents/kWh respectively46. The value of tariffs, premiums, supplements and cap & floor limits is annually updated, using the consumer price index (CPI) as a reference minus 0.25% until 31 December 2012 and minus 0.5% after that date. The details of the prices paid by the feed-in tariffs and premium price schemes as of 2009 are provided in Table 5-5 overleaf.

46 http://www.omel.es/frames/en/resultados/resultados_index.htm

http://www.omel.es/frames/en/resultados/resultados_index.htm


Table 5-5 Spanish feed-in tariffs for renewable energy

Source: Spanish renewable Energy Policy: Feed-in Tariff System, Hugo Lucas, IDEA, 2009.

AD utilisation in Spain to date In Spain, biogas production has mainly come from landfill sites, with AD plants playing only a marginal role. Whilst there does not seem to be an official register of AD plants publicly available, the research has identified 8 small agricultural AD plants (total of approx 3MWe) and another 15 larger AD plants treating MSW, with a total electricity production of around 26MW. The internet research showed that there are also 9 new small-scale AD plants planned for 2010, with a total additional electricity capacity of 17MW. Of the energy produced from biogas in 2007, only 8% were used for the co-generation of heat and electricity; the remainder (92%) was solely used for electricity47. According to a study conducted by ProBioGen PSE Spain has the potential to produce 8,000million m3 of biogas per year. This is based on the availability of 83.5 million tonnes of food and agricultural waste that Spain produces annually as part of its existing industries48. It is estimated that, if all the animal slurry potentially available in the country was utilised as a feedstock, biogas production from agricultural AD plants could reach approximately 50% of the overall biogas production by 203049.

47 Miguel Rodrigo, „Perspectivas del biogás en España‟, Departamento de Biomasa y Residuos, April

2009. 48

Mundoenergia, „España genera biogás agroindustrial en 8.000 millones de m3/año, 15/07/2009.

49

Miguel Rodrigo, „Perspectivas del biogás en España‟, Departamento de Biomasa y Residuos, April 2009.

http://www.mundoenergia.com/noticias/renovables/espana-genera-biogas-agroindustrial-en-8000-millones-de-m3ano-200907152507/


5.2.13 Sweden

Background Currently there are 226 plants in Sweden producing biogas producing approximately 1.3 terrawatts hours. Studies have concluded that the potential production in Sweden is approximately 10 times larger than this, or approximately 14 terawatt hours per year. Most of these developments have been made possible by state funding, administered by the Swedish Environmental Protection Agency through local investment programs (LIP) and climate investment programs (KLIMP) during the period 1998-2007. Many biogas plants have been built with contributions from LIP and KLIMP and a number of improvements and extensions to existing plants have also been financed in this way. The state investment programs have been an important driving force behind most Swedish biogas projects and in many cases have enabled the development of new technology and demonstration objects. Source: Report 5476, 2005, from the Swedish Environmental Protection Agency

Drivers for biowaste in Sweden include:

Investment grants for biological treatment 1998-2008

Tax on landfilling of organic waste (45 E/t) 2000

Environmental labelling of compost/digestate 2000

Tax exemption for biogas as vehicle fuel 2003

National targets for biowaste 2004-2010

Ban on landfilling of organic waste 2005

Tax on incineration of MSW (10-45 E/t) 2006 Specific Drivers for biogas production include:

High transportation cost for sludge

Reduce odour

Increased cost for waste handling

Waste problem for industry

Investing in power plant

Climate investments

Reduce carbon dioxide

The following are Swedish targets on Biowaste: • 2010: 50% of MSW is recycled, including biological treatment • 2010: 35% of food waste from MSW is recycled by separate collection and biological treatment (61 kg/inhabitant in 2007 including garden waste) • 2010: 100% of clean food waste from food industry is recycled by biological treatment • 2015: 60% of phosphorus from waste water is recovered

Sweden‟s target is 50% of energy from renewable sources by 2020, and that at least 10 % of energy use in the transport sector must also come from renewable sources by 2020. Due to relatively low electricity prices Sweden has invested in biogas as a transport fuel. It has put in place several incentive systems in favour of biogas, including carbon tax exemptions, investment subsidies for the construction of biogas units and incentives to buy cars that run on biofuels. Electricity produced from anaerobic digestion receives 45 öre/kW electricity with an additional possibility of 30 öre for Green Certificates.


Key biogas stakeholders and their areas of influence Government:

Legislation for production of biogas

Subsidies for local initiatives

Public procurement Municipalities

Environmental initiatives

Problem solving The Swedish green electricity certificates for renewable electricity is a similar system to the ROCs (Renewable Obligation Certificate) system in the UK50. Economical aspects on Biowaste include:

- Separate collection of biowaste-MSW is the major cost-driver. Treatment costs of food waste equal (incineration, digestion, composting)

- Landfill and incineration taxes have pushed alternatives - Important in Sweden: investment grants (30-50%), tax-reductions (on biogas as fuel,

on cars with biogas) - Private-public partnership in AD-plants (municipalities, farmers, energy companies)

Research of the Swedish Environment Technology Council (SWENTEC) found that the points listed below are some of the important factors that are required for a successful anaerobic digestion plant in Sweden:

- Good cooperation - Local firms that can provide raw materials - Proactive municipal management - Contractors available - Cost effective - Involved car companies - R&D and demonstration plants - Governmental subsidiaries

Common reasons for development of Biowaste in Scandinavia:

- Reduced landfilling of Biowaste (BW) is environmentally seen as most important. - Energy recovery “LCA-equal” to biological treatment of sep. collected BW from

MSW. - Focus on energy - less nutrients and compost as carbon sink. - Separate collection (SC) a condition for “clean” recycling of BW. No need for SC for

non-recycled BW, thus no binding requirement for SC of all BW. - Economic benefits from increased energy-prices last 10-20 years have made

Incineration (with heat and electricity recovery) and biogas plants more interesting. - Waste management is well developed, thus high recycling rates of other wastes

have already been achieved. - Compost as carbon sink is rarely considered

(The Kyoto protocol includes accounting for soil sequestrated carbon). AD utilisation in Sweden to date In Sweden the biogas production has been more or less constant over the past few years, and the number of plants has not changed significantly. However, there is a change in where

50 Source - Annelli Persson


the biogas comes from. The production from landfills has decreased as expected, while the production from sewage treatment plants and co-digestion plants has increased (Produktion och användning av biogas år 2006, ER 2008:02)51. In 2009 the total use of biogas in Sweden was 1.3TWh/a with a potential of 14TWh/a which would be equivalent to 20% of the total traffic consumption of biogas. Currently there are 8 farm plants, 3 industry plants, 17 co-digestion plants, 60 landfill plants, and 138 sewage treatment plants in Sweden which is a total of 226 biogas plants. Sweden has made significant advances in the exploitation of biogas as an energy source. There are 226 biogas plants in the country today (138 sewage treatment plants, 60 landfills 18 co-digestion plants, 8 farm scale, and 2 industrial). Most of the biogas (c. 60%) is produced at sewage treatment plants, while 30% comes from landfills and 10% from co-digestion plants. There are also eight smaller farm-scale biogas plants, which are mostly designed for electricity generation and heat production. Successful developments in Sweden during the last ten years have resulted in an increased use of biogas as a vehicle fuel. At present there are 38 upgrading plants in the country. Awareness of the advantages of biogas is increasing, such that the demand for biogas as a vehicle fuel is greater than the supply in some regions, such as the Stockholm area. New technologies for the purification and transport of biogas have been developed and the number of filling stations for biogas in Sweden is continuously increasing.

5.2.14 Switzerland

Background The development of agricultural biogas plants in Switzerland commenced in 1969 and reached a total of 135 before falling back to its current number of 69. Projects of national interest can receive a maximum of 8% of the investment costs. In some of the regions up to €40,000 is available per installation. Price given per kWh is in the region of 10 cent. The Swiss feed-in tariff system, like those in Germany, France and Spain, pays a renewable energy generator for every kWh of electricity generated. The payments are made for periods of 20 to 25 years, depending upon the technology. AD utilisation in Switzerland to date In Switzerland, only a small amount of the nationwide potential for biogas production has been mobilized so far.

51 Annelli Persson, Swedish Gas Centre


6.0 PLANT SCREENING AND SHORTLISTING

Based on the results of the scoring matrix (refer Section 4.3) the identified AD plants were ranked according to the total score of the overall plant performance. The 52 highest scoring plants (minimum score 15) were taken forward for detailed data analysis. These are shown in Table 6-1.

Table 6-1 Best scoring AD plants across all key performance indicators

Selection number

Actual rank Score Name/Location Country Operator/Vendor

1 1 25 BGA 26 Germany NQ-Anlagen-technik

2 1 25 BGA 05 Germany WELtec Bio Power

3 3 22.5 Svedjans biogasanläggning, Boden, Norrbotten

Sweden Läckeby Water AB

4 4 22 Kristianstad Sweden Kruger

5 4 22 Gærum Denmark 2B Biogas, Xergi

6 6 20.5 Bording Denmark Bording Biogasanlæg, Xergi

7 7 20 BGA 03 Germany Regio Energie-Systeme

8 7 20 Hasselager Denmark Hegndal, Dansk Biogas

9 9 19.5 Boden Sweden Läckeby Water AB

10 10 19 Skilleby gård Järna

Sweden Unknown

11 10 19 Hadsund Denmark Uhrenholtgaard Biogasanlæg, Xergi

12 12 18.5 Iggenhausen Germany I.O. Energie/ Schachtbau

13 13 18 BGA 21 Germany E.U.R.O Biogas

14 14 17.5 Helsingborg Sweden NSR

15 14 17.5 Bedsted Denmark Tinggaard Biogas,Xergi

16 14 17.5 Oelde-Stromberg Germany Erdmann/ Biogas Nord

17 17 17 Nimtofte Denmark Nimtofte Biogasanlæg, Xergi

18 17 17 DK-9700 Brønderslev Denmark Vester Hjermitslev Biogas Plant

19 17 17 Wallonia 3 Belgium Unknown

20 20 16.5 Skellefteå Sweden Läckeby Water AB

21 20 16.5 Jönköping Sweden Citec

22 20 16.5 Andreas Stimmer Germany UTS

23 23 16 Moscazzano, Cr Italy

24 23 16 Nynäs Gårds biogasanläggning, Nyköping, Södermanland

Sweden Affiliated with SMTC (Stockholms Miljoteknikcenter)

25 23 16 Alviksgården, Luleå, Sweden Dansk Biogas


Selection number

Actual rank Score Name/Location Country Operator/Vendor

Norrbotten

26 23 16 Skövde Sweden Business Region Goteborg, Goteborg Energi, FordonsGas

27 23 16 BGA 58 Germany Eisenmann

28 23 16 BGA 54 Germany Schmack Biogas

29 23 16 BGA 42 Germany BayWa

30 23 16 BGA 40 Germany Biogaskontor Koberle

31 23 16 BGA 39 Germany agriKomp

32 23 16 BGA 38 Germany UTS Biogastechnik

33 23 16 BGA 37 Germany BayWa AG

34 23 16 BGA 36 Germany Bio-Select

35 23 16 BGA 35 Germany Rohn GmbH/Schutter

36 23 16 BGA 33 Germany agriKomp

37 23 16 BGA 32 Germany Novatech

38 23 16 BGA 29 Germany Lipp GmbH/Rohn GmbH

39 23 16 BGA 19 Germany Biogas WeserEms

40 23 16 BGA 13 Germany BayWa AG

41 23 16 BGA 07 Germany Luthe

42 23 16 Lihme Denmark Baunsgaard Biogas, Xergi

43 23 16 Tirpersdorf Germany Aproha GmbH

44 44 15.5 Wrams-Gunnarstorp, Bjuv, Skåne

Sweden Bigadan A/S

45 44 15.5 PIRo Energie Germany UTS

46 44 15.5 Utzenaich Austria Oekoenergie Utzenaich Biog-Biogas

47 44 15.5 Grieskirchen Austria Oekoenergiepark Grieskirchen/ Enserv

48 44 15.5 Eggerding Austria Strasser

49 49 15 Pellegra Grande / Castelleone (CR)

Italy

50 49 15 Eslov Sweden Unknown

51 49 15 BGA 63 Germany BioFerm

52 49 15 Wittstock Germany Agrar GbR Marquardt

The overall top scoring list was subsequently compared with the top scoring lists of the KPIs „feedstock‟ and „energy data‟ in order to ensure that no high scoring AD plants in these areas were dismissed from the representative list due to a lack of data elsewhere. As a result the following plants (Table 6-2) were added to the representative list, bringing the total to 64.


Table 6-2 Additional top performing plants from KPIs ‘feedstock’ and ‘energy data’

Selection

number

Actual rank

Score

Name/Location Country Operator/Vendor

Feedstock

53 1 4 Unknown 24 Netherlands Unknown

54 1 4 Unknown 9 Netherlands Unknown

55 1 4 Kraft Germany Krieg & Fischer Ingenieure

56 1 4 Gundorf Germany Entec

57 1 4 Wels Germany Strabag

58 1 4 Vienna Austria RosRoca

Energy Data

59 3 3 BGA 63 Germany BioFerm

60 3 3 BGA 57 Germany Krieg & Fischer Ingenieure

61 3 3 BGA 50 Germany ARCHEA

62 3 3 Rappelsdorf Germany LPG Schleusingen

63 3 3 Dolgelin Germany LW Schulze

64 3 3 Wallonia 1 Belgium Unknown

Where possible the operators or technology vendors of the identified 64 AD plants were contacted to confirm whether they would be willing to participate in this study. Participating operators were asked to fill in a site visit protocol in order to receive detailed plant operation data required for this evaluation. The following sub-sections present the results of the detailed data analysis and the selection of the subsequent site visits.

6.1 Contact Detail Availability

The data collated during the literature review were partly directly from plant operators, but mainly from published research carried out in the past or from released government statistics. Some of the published research studies comprised detailed plant data but did not identify the operator or the location of the actual site. From this detailed data and information some of these plants rank in the top 64 of the scoring exercise, however, without any contact information they could not be included in the final site visit selection. This reduced the list for the potential site visit selection down to 36 plants. The available data of unknown operators were included in the technical review; however they have been taken out of the individual key performance indicator top ranking lists.

6.2 Feedstock

Of the 221 analysed plants a total of 80 plants (or 36%) used feedstocks specifically targeted by Defra, i.e. manure, slurry, food & garden waste. Paper and card was not used as a feedstock at any of the plants. Additional tonnage details were available for 21 of those 80 plants; therefore these plants form the top ranking list for the KPI “Feedstock”. An overview


of the feedstocks used and the capacities of the plants (where available) for the top ranking plants (of which the operator or the location was known) is given in Table 6-3.

Table 6-3 AD plants and tonnages using a mono- or mix of feedstocks targeted by Defra

KPI Feedstock - Summary

No of plants using targeted feedstock:

Of which:

- Manure

- Slurry

- Food& Garden waste

- Mix of feedstocks

80

3

2

11

64

Actual rank

Name/Location Country Feedstock Plant capacity

(t/a)

1 Läckeby Water AB Boden, Norrbotten

Sweden Sewage sludge Food waste

No data

1 Affiliated with SMTC Nyköping, Södermanland

Sweden Manure Food waste from restaurants & local grocery stores

No data

1 Kruger; Kristianstad Sweden Slurry Organic industrial waste Food waste Slaughterhouse waste

80,000- 100,000

1 Entec; Gundorf Germany Manure 41,000

1 Xergi ; Hadsund Denmark Manure 12,000

1 Xergi ; Bording Denmark Grass, Clover grass Ecological manure Vegetable wastes (carrots, oats, potatoes)

3,650

1 Xergi ; Nimtofte Denmark Manure Industrial organic waste Sewage sludge

3,650

1 Xergi ; Bedsted Denmark Pig manure 3,650

1 Xergi ; Lihme Denmark Manure Fatty residues

20,000

1 Xergi ; Gærum Denmark Pig manure Fatty residues

22,000

1 Dansk Biogas; Hasselager Denmark Manure Fatty residues

20,000

1 Strabag; Wels Austria Food & garden waste 15,000

1 RosRoca; Vienna Austria Food & garden waste 17,000


The AD plants using the targeted feedstock are spread over 10 countries with most plants being located in Germany (22), Sweden (18), Italy (13), and Denmark (7). In all other countries the feedstock appears to be generally mixed with a certain percentage of energy crops based on the data obtained in this study. The collated data showed that the vast majority of plant operators (80%) treat a mix of feedstocks and only very few plant operators (5%) treat exclusively farm animal wastes. The only other mono feedstock appears to relate to anaerobic digestion plants treating food waste from households and commercial sources. The treated tonnages range from 3,000t/year treating energy crops to 100,000 tonnes, when the plant only treats farm manures or slurries. Most farm-scale plants have a capacity between 5 and 20ktpa in this low energy range. With 22 identified plants Germany had the largest number of AD plants treating manure, slurry, and or food & garden/ plant waste only. However, to put this in context the percentage of plants treating the specified feedstock types is comparatively small based on the available data. It was found that the majority of farm-scale AD plants in Germany use a mix of energy crops and slurry. In Italy, the main feedstock of AD plants is animal slurry, with only a smaller fraction of agricultural waste/energy crops being used. This is directly linked to the geographical distribution of the plants, which are practically all located in the North of the country, where the majority of Italy‟s livestock farms are based. And, at a time when the livestock industry is suffering increasing costs and lower revenues, AD plants are becoming an increasingly important source of additional income. Denmark has an extensive pig production and therefore produces a significant volume of pig manure; Sweden also uses increased farm animal feedstocks due to its intense agricultural farming activities with extensive crop farming in the west region of Sweden. Based on the results of the feedstock analysis Germany, Italy, Sweden and Denmark are the countries most likely to resemble comparable conditions for potential small scale/ on-farm AD plants in the UK.

6.3 Type of AD System

Over two thirds (71%) of the collated data did not specify the type of AD system used (e.g. wet/dry, 1-stage/2-stages), or other plant specific details, such as the digester capacity, the residence time within the tanks, or the volume of available gas storage. Of the 64 plants for which at least some AD system details were available, 22 were part of the dataset that did not disclose the plant location, hence only 42 AD plants within this KPI were potentially suitable for a subsequent site visit. Comprehensive plant system data, including details on dewatering, digestate and gas storage, were only available for three plants. The AD system data that were available for these 64 plants are summarised in Table 6-4.


Table 6-4 Summary of available AD system details

Parameter No of plants using

this system

Digestion system

-wet (<15-20%)

-dry (20-40%)

- no data provided

43

6

15

No of process stages

- 1 stage

- 2 stages

- - no data provided

17

42

5

Process temperature

- mesophilic (<38°C)

- thermophilic (55-58°C)

- mesophilic & thermophilic


41

4

6

13

Residence time (d) 21-225

Digestate storage

- covered

- uncovered


12

24

28

Gas storage

-in digester/ post digester

- separate gas holder

- no data provided

36

11

17

The results in Table 6-4 show that the vast majority of farm-scale AD plants are operated under mesophilic conditions using a wet (<15% dry solids) AD system. Around two thirds of the evaluated plants are also based on a two-stage system, generally comprising a main digester and a post-digestion reactor, in which the produced gas is collected. Only a few plants have a separate gas storage tank. The type of storage for the produced digestate was not often provided; plants for which this information was available seemed to mainly use uncovered digestate storage tanks. Based on the findings of this KPI wet, mesophilic digestion systems with gas storage integrated in the digester/ post-digester appear to best represent the majority of farm-scale AD systems, most of which operated in 2 stages.

6.4 Technical Data – Plant Performance

The KPI “Plant performance” was created to evaluate the biodegradability of the various feedstocks at the given operating conditions. Of particular interest were the following parameters:

o Feedstock composition in tonnages; o dry solids and volatile solids content of feedstock(s);


o weight of digestate produced per tonne of waste feedstock (and reduction in biodegradability of organic feedstocks through the AD process);

o biogas production and/ or installed electrical CHP power o Reactor volume; and o Organic load in the digester (kg VS/m3 *d)

At this stage however only very limited data were available that could give sufficient indications on the actual plant performance associated with the respective feedstocks. Only 50 of the 221 plants surveyed provided some of the information sought. As before, for 22 of these plants the data were taken from a research study that did not give any details on the plant locations or the plant operators. The data provided by the plant operators were mainly relating to the dry solids content of the feedstock mix, the organic load, the digester volume and the installed electrical CHP engine efficiency. Whilst at this stage, due to the lack of data, it was not possible to form a proper relationship between the feedstock characteristics, the plant operation, and the associated biogas production, the available data did, however, give an indication as to which of the pre-selected plant operators were willing to contribute to this study and which type of data may be available for the detailed plant performance evaluation. Of the 39 operators that did provide at least some of the requested plant performance data 14 were from Sweden, 8 from Denmark, 4 from Germany and 1 from Spain. The outcome of this KPI confirmed Sweden, Denmark and Germany as the most suitable countries for the selection of sub-sequent site visits.

6.5 Energy Data

The aim of this KPI was to identify the electrical engine power installed at the sites, the actual amount of electricity produced, the parasitic electricity plant requirements, the quantity of heat produced and how this heat was utilised, if at all.

6.5.1 Installed electrical CHP capacity

For the purpose of this study only AD plants with a net rated thermal input from 0.15MW to 0.40MW were to be included in the research. Up to this limit AD plants can generally be classed as „small-scale‟ and are therefore most likely to be found in farm applications; 0.4MW is also currently the upper limit for qualifying for an environmental permit exemption. Plants that were outside this range were not taken forward into the scoring exercise. More than half (56%) of the collated information only contained information on the installed engine size. For an additional 24% the amount of electricity produced on site was also available. Only 44 plants gave further information on e.g. parasitic heat and electricity requirements, and/or on heat generation and utilisation.

6.5.2 Electricity utilisation

The feedstock tonnages range from 3,000t/a for a 160kWe engine up to 41,000t/a for a 360kWe engine. However, annual feedstock tonnages may vary significantly for a same sized engine. Figure 6-1 shows the feedstock tonnages for 30 of the reviewed plants in relation to the installed engine capacities.


0

5000

10000

15000

20000

25000

30000

35000

40000

45000

150 160 170 180 190 200 210 225 240 250 290 300 325 340 350 360 370 380 390 400

Installed engine capacity (kWe)

Pla

nt

thro

ug

hp

ut

(t/a

)

Figure 6-1 Annual plant throughput for CHP engines 0.15-0.4MWe

The graph shows that feedstock tonnages as low as 3,000t/a may produce enough energy to require the installation of a 340kWe engine; in other cases however an annual throughput of 41,000t/a only produces enough energy for a similarly sized engine . The plant with the small annual throughput and the comparatively high electricity generation uses a mixed feedstock of cattle and pig slurry (30%) and energy crops, such as maize and grass silage (70%); the plant with the high annual throughput of 41,000t purely treats manure in the AD plant. This confirms that the achievable electricity generation is dependent upon the energy potential of the type of feedstock utilised (refer to Section 3.3). As mentioned in Section 6.4 there was not sufficiently detailed information available to evaluate the actual biogas production rate or electricity generation per tonne of waste feedstock. The achievable energy production therefore had to be limited to feedstock mixes, with the additional limitation that the tonnage composition of the feedstock was unknown in most cases. Table 6-5 shows the type and amount of feedstock and the amount of electricity produced for a selection of the top ranking AD plants within this KPI.


Table 6-5 Specific electricity production rates for a range of feedstocks

AD plant operator (country)

Feedstock (t/a)

Feedstock(s)

(%age composition if available)

Electricity produced (kWh/a)

Electricity produced

(kWh/t input)

Oekoenergiepark Grieskirchen (A) 5,500

Energy crops (80%)

Cattle slurry (20%) 2,000,000 364

Oekoenergiepark Utzenaich (A) 10,400 Energy crop mix 4,350,000 418

BGA Eggerding (A) 13,700

Energy crops (67%)

Cattle slurry (30%)

Turkey manure (3%) 2,300,000 168

Wallonia 1 (B) 13,050

Cattle manure (37%)

Energy crops (9%)

Commercial food waste (54%) 2,260,000 173

Wallonia 3 (B) 7,070

Cattle slurry (75%)

Energy crops (5%)

Commercial food waste (20%) 1,700,000 240

BGA Winkler (Ger) 3,800

Energy crops (76%)

Cattle slurry (24%) 1,520,000 397

PIRo Energie (Ger) 8,400

Maize and grass silage (35%)

Cattle manure & slurry (65%) 1,520,000 181

Erdmann (Ger) 25,000

Cattle manure (18%)

Maize silage (62%)

Turkey&chicken manure(20%) 3,285,000 129

Unnamed 3 (NL) 36,000

Cattle manure

Poultry droppings 2,720,000 75

Unnamed 9 (NL) 5,000 Cattle manure, Poultry droppings, maize, foodwaste 1,528,000 305

Brunsbo, Skaraborg Götene Gårdsgas (Swe) 5,265

Manure (95%)

Potato – waste (5%) 1,800,000 N/A

Wrams Gunnarstorp, Bigaden A/S(Swe)

Pig manure (8%)

Waste food (76%)

Agricultural waste

Slaughterhouse waste (16%)

No electricity production. Only

gas. N/A

Brandstrupgaard, Rodkoersbro (DK) 18,200

Pig manure (85%)

Organic waste Glycerine by product of biodiesel production (15%) 3,800,000 208

Foulum (DK) 30,000

Manure (75%)

Energy crops (20%)

Fatty residues from industry (5%) 6,056,797 202

2B Gaerum (Dk) 13,500

Pig manure (74%)

Fatty Residues (glycerine) & sludge from fish cleaning (26%) 3,200,000 237

Bertesago, Moscazzano, Cr (I) 9,100

Pig slurry (60%)

Maize silage (28%)

Glycerol (12%) 3,145,000 346

Pellegra Grande, Cr (I) 18,257

Cattle slurry (99.9%)

Maize silage (0.1%) 3,900,000 214

Formigara (Cr) 42,000

Pig manure (52%)

Cattle manure (4%)

Maize silage and other biomass (44%) 9,375,000 223

The results showed that AD plants treating a certain percentage of energy crops and food waste have a higher electricity production rate per tonne of waste feedstock (168 -


418kWh/t) than plants treating manure and or slurries only (~75kWh/t), or plants that only include a small percentage of energy crops. Based on these examples the specific electricity production ranged from 75-418kWh with an average of electricity production of 237kWh/t input. The average electrical engine efficiency was quoted to be 38%. When provided, the parasitic electricity demands were quoted to be between 6 and 8%. The remaining surplus electricity may be exported into the grid. Noticeable were the comparatively high electricity yield of Oekoenergiepark Utzenaich in Austria and the below average electricity production of the biogas plant Erdmann in Germany. Whilst high electricity yields may be expected from an AD plant that solely uses energy crops, the Erdmann plant also uses a high percentage of maize silage (62%) and the below average electricity yield of 129kWh/t is therefore surprising. Both plant operators were therefore asked to facilitate a site visit in order to identify any variations in the plant operation, and thus the potential reasons for the different electricity yields. Azienda Agricola Bertesago (Moscazzano, Cr), one of the two plants we visited in Italy, stated that in recent months they have started replacing some of the maize silage feedstock with glycerol. This has produced a significant increase in the amount of biogas produced by the facility, now reaching a well above average 346 kWh/t, despite the majority of its feedstock (60%) being pig slurry.

6.5.3 Heat utilisation

Information on heat utilisation was only available for 44 (or 20%) of the plants. Excluding the plants where the location was undisclosed this number was reduced to 20 plants. Generally the information provided was limited to the type of heat utilisation rather than the amount of heat produced and utilised annually. Most plants utilise at least some of the heat for digester heating, office and farmhouse heating. Where stables are on site the heat is utilised for the stables, especially for piglets and chicken pens, which require high temperatures. The Oekoenergiepark Grieskirchen utilises the heat for the adjacent biomass burner. Here, the biomass burner was built in 2002 and complemented by an anaerobic digestion plant in 2006. Although both plants are managed as separate businesses, they are operated in synergy. Other plants in Austria, and also some plants in Germany, use the heat for cereal or woodchip drying. Due to the lack of incentives for renewable heat production, in Italy the focus of AD operators has been mainly on the production of electricity, with heat being used only for the parasitic requirements of the plant and needs of the farm. The site visits however indicated that around 50% of the heat produced in winter can be used a on the farms with livestock. In order to get more information on successful heat utilisation concepts following plants were selected site visits:

o Oekoenenergiepark Grieskirchen, Austria o BGA Iggenhausen, Germany

6.6 Other Information

Key Performance Indicators were also created for „other technical considerations‟, such as digestate end-use and operational issues, and for „Emissions‟ in order to identify the


respective national emission control requirements and the conditions of the environmental permitting routes. The collated data generally did not contain any data on operational issues and only a very small percentage (5%) of operators stated the digestate end-use; this was found to be almost exclusively used as natural fertiliser on farmland. Equally, there were only very few data available on emission control. The only information that was provided stated the existence of a gas flare or a biofilter. Due to the extensive lack of data in these areas it was decided to investigate these issues as part of the actual site visits. The findings are presented in Section 7.2.

6.7 Final Site Visit Selection

The score of each KPI was multiplied by a weighting factor, depending on its relevance to the key project aims (refer Section 4.3). The sum of the individual KPI scores was then used to create a top-ranking list for the overall performance of each plant and its suitability to contribute more valuable information during a subsequent site visit. In total 52 plants had a minimum score of at least 15. The location and the plant operator could not be identified for 21 of these plants. The remaining 31 plant operators, including those specifically identified as part of the individual KPI parameters, were contacted and asked whether they would be willing to facilitate a site visit. Table 6-6 lists the known 31 top-ranking AD plants. Highlighted are the plants where a site visit was agreed to and that were subsequently visited. The results of the actual site visits are presented in Section 7.


Table 6-6 Overall top-ranking AD plants

Selection number

Actual rank


3 3 Svedjans biogasanläggning, Boden, Norrbotten

Sweden Läckeby Water AB

4 4 Kristianstad Sweden Kruger

5 4 Gærum Denmark 2B Biogas, Xergi

6 6 Bording Denmark Bording Biogasanlæg, Xergi

8 7 Hasselager Denmark Hegndal, Dansk Biogas

9 9 Boden Sweden Läckeby Water AB

10 10 Skilleby gård Järna

Sweden The Biodynamic Research Institute, Järna

11 10 Hadsund Denmark Uhrenholtgaard Biogasanlæg, Xergi

12 12 Iggenhausen Germany I.O. Energie/ Schachtbau

14 14 Helsingborg Sweden NSR

15 14 Bedsted Denmark Tinggaard Biogas,Xergi

16 14 Oelde-Stromberg Germany Erdmann/ Biogas Nord

17 17 Nimtofte Denmark Nimtofte Biogasanlæg, Xergi

18 17 DK-9700 Brønderslev Denmark Vester Hjermitslev Biogas Plant

20 20 Skellefteå Sweden Läckeby Water AB

21 20 Jönköping Sweden Citec

22 20 Andreas Stimmer Germany UTS

23 23 Moscazzano, Cr Italy Thoeni

24 23 Nynäs Gårds biogasanläggning, Nyköping, Södermanland

Sweden Affiliated with SMTC (Stockholms Miljoteknikcenter)

25 23 Alviksgården, Luleå, Norrbotten Sweden Dansk Biogas

26 23 Skövde Sweden Business Region Goteborg, Goteborg Energi, FordonsGas

42 23 Lihme Denmark Baunsgaard Biogas, Xergi

43 23 Tirpersdorf Germany Aproha GmbH

44 44 Wrams-Gunnarstorp, Bjuv, Skåne Sweden Bigadan A/S

45 44 PIRo Energie Germany UTS

46 44 Utzenaich Austria Oekoenergie Utzenaich Biog-Biogas

47 44 Grieskirchen Austria Oekoenergiepark Grieskirchen/ Enserv

48 44 Eggerding Austria Strasser

49 49 Pellegra Grande / Castelleone (CR)

Italy agricomp

50 49 Eslov Sweden Sydgas AB


Selection number

Actual rank


52 49 Wittstock Germany Agrar GbR Marquardt

In total 18 site visits could be arranged as some technology providers offered to show some additional plants. 7 of these sites were in Denmark, 4 in Germany, 3 in Austria, 2 in Sweden, and 2 in Italy.


7.0 FINDINGS FROM OPERATING AD PLANT VISITS

7.1 Overview

The findings from the literature review, in which data for a total of 862 European small-scale/ on-farm AD plants were collated, and the subsequent Key Performance Indicator scoring analysis carried out for 221 of these plants, provided a comprehensive overview on the types and operation of AD technology used on farms across Europe. It also provided a wide-ranging overview on the governmental strategies and subsidies provided to promote this sector for the production of renewable energy. At the same time these data provided the basis for the selection of representative AD plants for a detailed analysis of the plant operation on site (refer to Section 6). The operational AD biogas plants for site visits were chosen to provide a representative sample of a wide range of different plant types, range of feedstocks, and methods used in countries where the technical and agricultural conditions are broadly similar to those in the UK. In accordance with the results of the detailed data analysis, site visits were undertaken in Austria, Denmark, Germany, Italy and Sweden. No individual technology provider was selected favourably as part of the selection process, although some vendors did offer to show additional plants when they were contacted by SLR. These additional plants have also been included in the case study review. A summary of the concept of each AD plant is briefly described, and operational plant and performance data are displayed in a uniform table style for ease of comparison. The feedstock and biogas- and electricity production data provided by the plant operators are based on data generated during 2009 and therefore represent the average plant performance data across the seasons. The selected plants were all built and commissioned after the year 2005; they are therefore considered to represent current state-of-the-art AD technology that also has a proven operational track record. In summary the data showed that the preferred technology for modern AD plants is based on wet, mesophilic digestion systems with gas storage being integrated in the digester/ post-digester vessels. The majority of AD plant operators also prefer the digestion of mixed feedstock over the use of single-source or mono-feedstocks. Typically farm wastes like animal manure and slurry are mixed with energy crops such as maize- and grass silage, or other plant wastes. This is partly a consequence of the governmental incentives introduced in some countries to promote the use of energy crops, but is also partly due to the increased gas yield generated by these crops compared to manure and slurries on their own. The key findings of the site visits are summarised in this section; the individual site visit reports, including the plant performance data are included as Appendix F.

7.2 Key Findings from Plants Visited

During the site visit the AD plant operators were asked for the following information:

o Type of planning permission(s) required; o Type of AD system, including gas storage; o Type, tonnage, and characteristics of feedstock(s); o Size of farmland/ animals in relation to feedstock; o Installed electrical CHP engine capacity; o Amount of biogas produced and type of biogas utilisation; o Amount of electricity produced and parasitic electricity requirements;


o Heat utilisation; and o Grants and subsidies received (in 2010).

The information was used to evaluate the impacts of the national planning regulations and the feedstock related performance on the choice of AD technology and feedstocks used. The findings are summarised in the following sub-sections.

7.2.1 Required Planning Permissions

In Germany, small AD plants have to be built in compliance with the national construction law. The law also covers a number of environmental aspects, such as noise and odour emission control. The location of the plant therefore defines whether a biofilter has to be included in the design; it is not compulsory in the first instance. Equally, there is a plant size limit that defines whether the plant has to be built in accordance with the German Emission Control Regulations, the “Bundesimmissionsschutzgesetz” or “BImschG”. This is important, as plants abiding to this law are automatically required to have a gas flare on site. Plants with a thermal firing rate of <1MW are exempt from these regulations and are permitted to operate the plant without the installation of a gas flare, as long as they a) provide a connection point for a mobile gas flare and also have a contract with a mobile gas flare provider located within 30 minutes of the plant or b) install 2 CHP engines, so that 1 engine is always available on stand-by. As a result of this exemption 3 of the 5 plants visited in Germany did not have a gas flare on site. According to literature52 42% of the AD plants were granted planning permission under the construction law rather than under BImschG. An additional planning requirement is the installation of leak proof silos and the capture of any leachate water from these silos in accordance with the German Groundwater Regulations. According to the plant operators this environmental planning requirement has the greatest impact on the capital costs of an AD plant. In Austria all plants also have to be built in compliance with the national building law, but they are not exempt from gas flare installations. Additionally, in Upper Austria it is required to implement a heat recovery plan; without such a plan, planning permission will not be granted. As a result all AD plants in Upper Austria utilise the produced heat, mainly for woodchip or grain drying. In Italy, authorisation for building AD plants is granted by the provincial authorities (Counties) and requirements can vary for different areas. Nevertheless, this will have to be in compliance with the DLvo 387/03 decree, which states that “plants for the production of electricity supplied from renewable sources can be located in areas classified as agricultural by existing urban development plans”, with the requirement though that “the proposed location of the plant must take into account existing provisions in support of agriculture, with particular reference to the development of local food traditions, protection of biodiversity, as well as cultural heritage and rural landscape, in order to preserve the integrity of the land and protect specific agronomic characteristics of the area and the staying on-site of specialised agricultural workforce”. The individual national planning requirements clearly have an impact on the design of the AD plants but also on the development of renewable energy utilisation. AD plants in countries where heat utilisation is encouraged through possible subsidies, but not compulsory, tend to utilise heat only when local heat users are readily available and viable. In Germany the introduction of a heat bonus has increased the percentage of heat utilisation from AD plants to over 50%. Extra measures, such as added woodchip or plant drying, are

52 German Biomass Research Centre, 2009: Monitoring zur Wirkung des EEG auf die Entwicklung der

Stromerzeugung aus Biomasse (Electricity production from Biomass)


rarely implemented. Equally, the air emission exemption available to small scale AD plants in Germany results in the omission of gas flares at many farm-scale plants. Instead, farmers reported that they vent the methane-rich biogas into the air uncontrolled, during engine downtime, leading to high greenhouse gas emissions. Open digestate storage tanks (coverage not legally controlled) add to these emissions. The effect of this source of emissions is attracting concern and is currently being reviewed and discussed by operators and regulators in this sector in Germany. The most important relevant environmental permits and exemptions of the visited countries are summarised in tabular format in Appendix G.

7.2.2 Grants and Subsidies

A large number of European member states now subsidise electricity and heat production from renewable sources, such as biogas (refer Section 5). The level of subsidies paid per kWh is country specific, not only in terms of the amount paid but also with regards to how the sum of subsidies is made up. Since the renewable energy act came into force in 2004 (amended 2009) the number of farm-scale AD plants built in Germany has soared due to farmers being attracted to the considerable bonus payment. The actual bonus paid for each kWh of electricity sold depends on the feedstocks used, the type of applied technology (expired in 2008), the electricity tariff, and the heat utilisation. For example, a farmer who treats a minimum of 30% of animal waste (manures/ slurry) and up to 70% of energy crops and who also utilises the heat for woodchip drying receives the following subsidy for each kWh of exported electricity: Example subsidies: Use of Energy crops: 7€c/kWh Use of at least 30% of animal wastes: 4€c/kWh Current electricity tariff: 7€c/kWh Heat utilisation: 2€c/kWh Total “sales” price: 21€c/kWh The current pricing structure has a huge impact on the feedstocks used. Due to the extra 4€c/kWh paid for the treatment of at least 30% manure and or slurry, and the 7€c/kWh paid for the use of energy crops every site visited in Germany treated at least 30% of these animal wastes and every site also treated large amounts of energy crops. Up until 2008 there was also a technology innovation bonus of 2€c/kWh paid for the use of dry anaerobic digestion technology in order to promote this type of AD treatment. However, the benefits of using this technology over wet digestion were found to be limited and the bonus was removed. Dry AD plants which were built prior to removal of the bonus still benefit from the extra payment for a limited period. In Austria there is a fixed bonus of 11.5€c/kWh of electricity produced, independent of the type of feedstock or the type of technology used. Additionally the government reviews annually whether this bonus shall be increased. In 2009, the bonus was increased by 4€c to 15.5€c/kWh; in 2010 the extra payment was reduced to 3€c, offering the current total of 14.5€c/kWh of electricity produced. The payments reduce significantly, if no heat plan is implemented. The bonus payment does not appear to have a direct impact on the type of feedstock treated, although energy crops are largely used due to their higher biogas production ability. All sites visited in Austria claimed that a minimum bonus of 14€c/kWh is required to make the operation of the AD plant economically viable. The use of feedstocks with high energy potential seems therefore imperative.


In Italy, the feed-in tariff in particular provides a very significant incentive of 28€c/kWh, which is the main reason behind an almost exponential increase in the number of AD plants being developed in Italy over the last two years. Plants that became operational before 2008 appear to be disadvantaged as the level of subsidy they receive is significantly lower, being less than half of the one provided by the feed-in tariff scheme (Refer to Section 5.2.8).

7.2.3 Development in Agricultural AD Technology

The rapid increase in the use of AD in agriculture has led to a fast and broad development in available AD technologies and technology suppliers. As described in the previous sections, both planning permission requirements and available bonus schemes have had a significant influence on the actual AD technology development. In Germany, the dry solids content of the mixed feedstock is generally below 20%, enabling the treatment in the well-established wet AD system, which are predominantly used in Germany. The reactors are generally cylindrical and equipped with a mixing system, which is important to avoid material deposits and to prevent foaming and thus, inhibit the biogas flow. At high %DS contents the feedstock material is often mixed with liquid digestate to maintain the pump-ability of the substrate. Other technologies separate solid and liquid feedstock transfer into the digester to prevent potential blockages. The solids feedstock is then transferred via screw conveyor from a solids container to the digester. Some solids containers are equipped with walking floor for automated feed operation. The introduction of the innovation technology bonus for dry digestion systems briefly led to a small increase in the installation of dry AD systems, however in total there are still only around 8% of plants based on this system and this particular innovation bonus has since been withdrawn. One known problem of single-staged dry digesters is the deposition of carbonates in pipes and pumps due to the slight alkaline conditions within the reactor as a result of the hydrolysis. This may lead to blockages in the recirculation system. The use of 2-staged systems may prevent carbonate depositions, as it allows flushing the pipes of the first stage (hydrolysis) with digested process water from the digestion phase. The materials used for the digester vary. The reactors are generally made of concrete, or stainless steel. The use of stainless steel pipes was also often recommended in order to prevent accelerated wear and tear. The mixing systems are often based on submerged electrically driven mixers or on paddle mixing. Paddles may be installed in the centre of the tank, at the side walls or may be diagonally submerged into the material. As part of this study no clear trend of the preferred mixing option could be identified. For the type of feedstocks used, pasteurisation is generally not required and most plants are operated under mesophilic (35-39°C) conditions. Mesophilic bacteria populations are not susceptible to changes in the feedstock and farmers visited on site described the process as “robust and easy to control”. Thermophilic bacteria populations are reported to be less diverse and potentially more sensitive to process and temperature fluctuations, especially temperature drops. Depending on the type of feedstocks treated, mixed mesophilic and thermophilic operation may also be used in two-staged systems, although this process principle was only applied by around 8% of the plants analysed as part of this study. The advantages and disadvantages of the different temperature conditions are summarised in Table 7-1


Table 7-1 Overview of operational temperature options for two-staged systems53

Digester Post-digester Advantages Disadvantages

Mesophilic mesophilic Stable biology population Prolonged biodegradation

Thermophilic mesophilic Rapid biodegradation, improved transport conditions of liquidised material downstream

Biology population sensitive to process changes

Mesophilic thermophilic Stable biology population with slightly increased biogas production and good transport conditions from post-digester stage

increased ammonia concentration in biogas affecting CHP engine

Thermophilic thermophilic Increased biogas yield but with reduced methane content)

Process sensitive, potentially resulting in decreased energy production

Thermophilic processes are also reported to potentially produce a higher concentration of spurious gases, such as sulphuric acid and nitrous oxides. This can potentially lead to increased corrosion and concentrations in the exhaust gas from the CHP, if no secondary measures as part of the engine operation are undertaken. In addition, the increased heat requirement for the thermophilic process also reduces the heat available for export and as a result also reduces the financial benefits and the overall CO2 reduction potential. Mesophilic processes require prolonged residence times for similar biodegradation rates. Insufficiently degraded material may result in methane emissions where uncovered digestate storage tanks are used. Over two thirds of the plants operating in Germany and Austria are based on a 2-staged system, partly because single digesters with an uncovered digestate storage tank are also classed as 2-stage system (due to the fact that gas is collected in one tank but not in the other) and many of the older plants are designed that way. Nowadays, uncovered digestate storage tanks are not considered to be state-of-the-art technology. Based on the site visits and technology supplier information, plants installed after 2006 are designed with covered digestate storage tank, which has become the design of choice. The storage tank is also often used as post-digester. The clear advantage of this system is the capture of additional biogas for energy production and the simultaneous emission control of methane gas. The former has the additional financial advantage attached to it. Depending on the residence times, an additional 5-12% of biogas may be extracted from the post-digestion/ storage phase. Most plants operate a continuous feed system, as it enables increased biogas production at reduced residence times in a 2-staged system, due to the increased biodegradation phase and the reduction of fresh matter loss caused by short circuiting. As mentioned previously, this operational mode also prevents the potentially high methane losses to atmosphere. In 2-staged systems de-sulphurisation is predominantly carried out within the post-digestion reactor. The growth of sulphurous bacteria is supported by injecting a small amount of air into the post-digester (<1%) and by installing a grid above fill height on which the bacteria population can grow.

53 Jan Postel et al, Umweltbundesamt, Dec. 2009: Stand der Technik beim Bau und Betrieb von

Biogasanalgen (State of the Art for the design and operation of biogas plants)


The produced biogas is generally collected and stored in the roof of the digester or post-digester. In this case the roof is made up of a double membrane with an air cushion between the two layers. Digesters with a concrete roof have limited gas storage capabilities. In these cases, external gas holders are often used. Outdoor gas holders are also equipped with a double membrane; single membrane gas holders have to be housed. The produced digestate is still biologically active, albeit to a very limited extent depending on the plant performance, and will therefore still contribute to residual methane emissions. Optimised residence times within the digester (3-5 weeks depending on the feedstock) and aeration of the extracted digestate material enables a change from anaerobic to aerobic conditions, and thus resulting in reduced methane and odour emissions.

7.2.4 AD Plant Performance

The performance of the visited plants was evaluated based on their feedstock related energy potential and their actual electricity and heat production, the method and degree to which the energy was utilised, the operational plant issues experienced, and on emission handling on site. The findings are summarised in the following sub-sections. Feedstocks & theoretical energy potential Most of the visited plants treated a mix of feedstocks. The actual mix used on these sites and the theoretical energy potential (refer Section 3) for each of the feedstocks are shown in Table 7-2. Where a mix of energy crops was used an average energy potential was applied.

Table 7-2 Theoretical energy potential of feedstocks used on visited sites

Plant Feedstocks(s) (t/a)

(%)

Theoretical methane potential

(m3/t fm)

1

Theoretical methane production m

3/ year

Oekoenergiepark Grieskirchen (A)

Grass & maize silage

Cow slurry2

Total

4,380

1,095

5,475

80%

20%

85 -110

12-18

372,300 - 481,800

13,140 – 19,710

385,440 - 501,510

Oekoenergiepark Utzenaich (A) Mix of silages 10,400

100%

85 -110

884,000–1,144,000

BGA Eggerding (A)


Cow slurry2

Turkey manure

Total

9,200

4,000

500

13,700

67%

29.5%

3.5%

85 -110

12-18

42-54

782,000 – 1,012,000

48,000 – 72,000

21,000 – 27,000

851,000- 1,111,000

BGA Stimmer (Ger)


Cow slurry2

Cow manure

Total

3,285

1,095

912

5,292

62%

21%

17%

85 -110

12-18

24-30

279,225 – 361,350

13,140 – 19,710

21,900 – 27,375

314,265 – 408,435

PIRo Energie (Ger)


Cow slurry2

Cow manure

Total

2,920

3,320

2,190

8,430

35%

39%

26%

85 -110

12-18

24-30

248,200 – 321,200

39,840 – 59,760

52,560 – 65,700

340,600 – 446,660

BGA Winkler (Ger)


Cow slurry2

Total

2,920

912

3,832

76%

24%

85 -110

12-18

248,200 – 321,200

10,950 – 16,425

259,150 - 337,625

BGA Erdmann (Ger)

Maize silage

Cow manure

Turkey & chicken manure

Total

15,500

4,800

4,900

61.5%

19%

19.5

85 -110

24-30

42-54

1,317,500 – 1,705,000

115,200 – 144,000

205,800 –264,600


Plant Feedstocks(s) (t/a)

(%)

Theoretical methane potential

(m3/t fm)

1

Theoretical methane production m

3/ year

25,200 1,638,500 – 2,113,600

BGA IO Energie (Ger)

Maize silage

Turkey manure

Total

10,950

1,095

12,045

91%

9%

85 -110

42-54

930,750 – 1,204,500

45,990 – 59,130

976,740 – 1,263,630

Azienda Agricola Bertesago (I)

Maize silage

Pig slurry

Glycerine

Total

2,555

5,475

1,095

9,125

28%

60%

12%

85 -110

12-24

250-350

217,175 – 281,050

65,700 – 131,400

262,800- 383,250

545,675 – 795,700

Pellegra Grande (I)

Gras & maize silage

Cow slurry1

Total

73

18,250

18,323

0.5%

99.5%

85 -110

12-18

6,205 – 8,030

219,000 – 328,500

225,205 – 336,530

Brandstrupgård, Rodkoersbro Lundsby (DK)

Pig manure

Organic waste Glycerine, by-product of biodiesel production

Total

15,470

2,370

18,200

85%

15%

33 - 39

250-350

510,510 - 603,330

592,500 – 829,500

1,103,010 – 1,432,830

Foulum Xergi (DK) Manure

Energy crops

Fatty residues from industry

Total

22,500

6,000

1,500

30,000

75%

20%

5%

24 - 39

85-110

250-320

540,000 -877,500

510,000 - 660,000

375,000- 480,000

1,425,000 - 2,017,500

2B Gaerum Xergi Pig manure

Fatty Residues (glycerine) & sludge from fish cleaning

Total

10,000

3,500

13,500

74%

26%

33-39

250 - 350

330,000 - 390,000

875,000 - 1,225,000

1,205,000 - 1,615,000

Skinnerup Lundsby (DK)

Pig manure

Animal intestines

Total

13,140

3,285

16,425

80%

20%

33-39

12-42

433,620- 512,460

39,420- 137,970

473,040- 650,430

Tovgård Lundsby (DK) Pig manure

Animal intestines

Wheat

Total

13,140

2,957

329

16,425

80%

18%

2%

33-39

12-42

52

433,620- 512,460

35,484 – 124,194

17,108

486,212 – 653,762

Ellemegården Lundsby (DK)

Grass silage

Fatty residues

Total

9,855

1,095

10,950

90%

10%

87-110

250-320

857,385- 1,084,050

273,750- 350,400

1,131,135- 1,434,450

Nimtofte Xergi (DK) Pig manure

Fatty residues

Maiize silage

Total

8,000

2,000

950

10,950

73%

18%

9%

33-39

250-350

85 -110

264,000- 312,000

500,000- 640,000

80,750- 104,500

844,750 – 1,056,500

Brunsbo, Skaraborg Götene Gårdsgas (Swe)

Manure

Potato – waste

Total

5,000

265

5,265

95%

5%

24-39

35-50

120,000 -195,000

9,275 – 13,250

129,275 - 208,250


Pig manure

Waste food

Agricultural waste

Slaughterhouse waste

Total

3,160

30,000

6,320

39,500

8%

76%

16%

33-39

49- 74

12- 36

104,280 -123,240

1,470,000 - 2,220,000

75,840 - 227,520

1,650,120 - 2,570,760

Note 1) The methane potential was calculated using the theoretical waste characteristics displayed in Section 3, Table 3-1; 2) 1m

3 of slurry assumed to be equal to 1t in weight


Pure methane has an energy value of 9.97kWh/Nm3. (dry, 0°C and 1013mbar). The methane production of the plant can therefore be used to calculate the energy potential of the specified feedstock. In Table 7-3 the actual electricity production of each plant is compared with the theoretical electricity production based on the calculated methane production per year (Table 7-2) and an assumed electrical engine efficiency of 38%.

Table 7-3 Theoretical and actual electricity production of visited plants

Plant

Theoretical methane production

m3/ year

Theoretical electricity

production

MWh/ year

Actual plant electricity production

MWh/ year Deviation

1

(%)

Oekoenergiepark Grieskirchen (A) 385,440 - 501,510 1,465 – 1,906 2,000 + 5%

Oekoenergiepark Utzenaich (A)

884,000–1,144,000 3,359 - 4,347 4,350 ok

BGA Eggerding (A) 851,000- 1,111,000 3,234 – 4,222 2,300 -29%

BGA Stimmer (Ger) 314,265 – 408,435 1,194 – 1,541 3,040 +100%

PIRo Energie (Ger) 340,600 – 446,660 1,294- 1,697 1,520 Ok

BGA Winkler (Ger) 259,150 - 337,625 985 – 1,283 1,5203 +18%

BGA Erdmann (Ger) 1,638,500 – 2,113,600 6,226 – 8,032 3,285 -47%

BGA IO Energie (Ger) 976,740 – 1,263,630 3,712 – 4,802 4,400 Ok

Azienda Agricola Bertesago (I) 545,675 – 795,700 2,074 – 3,024 3,145 +4%

Pellegra Grande (I) 225,205 – 336,530 856 – 1,279 3,900 +300%

Brandstrupgård, Rodkoersbro Lundsby (DK)

1,103,010 – 1,432,830 6,443 -6,795 3,600-4,000 -44%

Foulum Xergi(DK) 1,425,000 - 2,017,500 5,415 – 7,666 6,056 ok

2B Gaerum Xergi (DK)

1,205,000 - 1,615,000 4,579 – 6,137 2,190 -52%

Skinnerup Lundsby (DK)

473,040- 650,430 1,797 – 2,471 2,700 +9%

Tovgård Lundsby (DK)

486,212 – 653,762 1,847 – 2,484 2,700 +9%

Ellemegården Lundsby (DK)

1,131,135- 1,434,450 4,298 – 5,451 3,000 -31%

Nimtofte Xergi (DK) 844,750 – 1,056,500 3,210 - 4015 No data provided

n/a

Brunsbo, Skaraborg Götene Gårdsgas (Swe)

129,275 - 208,250 491 - 797 Not in operation yet

n/a


1,650,120 - 2,570,760 6,270 – 9,768 Only produce biogas for

biomethane

n/a

Note 1) Plant in commissioning phase; design value only; 2) Deviations are based on difference to calculated theoretical maximum electricity production when the actual plant has produced more electricity and on the minimum theoretical value when the plant underperforms


The results show that around half (8) of the visited plants (19) produced an annual amount of electricity in line (+10%) with the expectations based on the theoretical energy potential of the feedstocks used. The electricity production for the AD plant BGA Winkler was stated to be 18% higher than the theoretical electricity production that was calculated for this feedstock mix. However, the reported electricity production is actually a plant design figure; the plant was still in the commissioning phase when visited and insufficient data were available at this stage to confirm the actual plant performance. The electricity production of the AD plant Biogas Stimmer was twice the amount of that calculated; the electricity production of the Italian plant Pellegra Grande was 3 times over the expected electricity amount. There are several reasons that may explain the significant differences between actual and theoretical electricity production. At BGA Stimmer the operator was not present during the site visit. It can therefore be assumed that the technology provider stated the design value rather than the actual performance data of the plant. The operator also recently added a second CHP engine to the plant. It can be assumed that the additional feedstock was not yet added to the feedstock data provided. Careful operation of the plant may also result in higher than average methane concentrations and in increased biogas production, which would consequently result in a higher electricity production. Additionally, the residence time in the reactor was quoted to be 80 days. This is deemed to be sufficient time to allow the complete biodegradation of the majority of the feedstock, again resulting in a higher than average biogas production. Whilst a combination of these reasons may justify the high electricity production at BGA Stimmer, it does not explain the extraordinarily high electricity production stated by the operator of the Italian plant at Pellegra Grande. This plant almost solely operates on cow slurry, a substrate which is known to have a relatively low energy potential (20-30m3 of biogas/t input, CH4 content 60%). Even a well operating plant is not expected to produce much in excess of 1,500MWh of electricity per year, based on a feedstock of 18,250 tonnes. This operator claims to produce more than 2.5 times of this amount. Details of the feedstock characteristics (DS, VS, CH4 content) were not available; therefore a detailed evaluation on the actual energy potential of the feedstock could not be carried out. However plants using this as a single feedstock will be very sensitive to the water content of the manure/slurry feedstocks and where this is effectively controlled by farmers at source, improvements in gas yield are quite likely. Some (5) of the plants produced less electricity than would be expected. BGA Eggerding uses a mix of feedstocks, many of which have a dry solids content (e.g. corn-cob mix, plant and maize silage and turkey manure). The digestion process is based on a wet, mesophilic system using a „ring-in-ring‟ digester. Here, it is possible that the high dry solid concentrations (30-34%) in the digester lead to sub-optimal operating conditions. Possible reasons for the underperformance may include excessive organic loads (kg VS/m3*d) in the reactor leading to acidification within the digester, which results in reduced activity of methane bacteria and thus, in a reduction of biogas production. The high dry solids content may also cause reduced mixing within the reactor and again this potentially leads to reduced biodegradation to the limited surface area being available to the bacteria population. The operator of BGA Erdmann, another underperforming plant, even admitted that he operated the plant at very high organic loads of around 8 kg VS/m3*d. For optimal conditions the organic load should not exceed 5-6 kg VS/m3*d. Three of the Danish plants also produce less electricity than would be expected from this type of feedstock. However, in the case of Gaerum and Brandstrupgård it is possible that the theoretical energy potential was overestimated. Both plants use a mix of organic wastes, including glycerine. Whilst the actual amount of glycerine treated may be low the theoretical energy potential for this feedstock was based on the methane potential just for glycerine.


Since no operational problems were reported on site it can be assumed that the difference stems from the way the theoretical energy potential was calculated. This theory is supported by the statement of one operator who reported that the price of glycerine has risen sharply in recent years, which led to a reduction in its use as a feedstock. The last underperforming plant, Ellemegården, reported to have had feedstock shortages in 2009, which explains the reduced electricity production at this site. One Swedish plant was not yet in operation did not provide any electricity details, and one of the Danish plants (Nimtofte) did not provide any electricity details. These plants were therefore excluded from this specific evaluation. Energy utilisation All of the visited plants utilised the produced biogas for energy production. Most plants produced heat and electricity, but only a part of these also utilised the heat. In few cases the biogas was upgraded to biomethane for use as a vehicle fuel. Electricity 16 of the 19 visited plants produce a total of around 6.2MW electricity, which is 390kW per plant on average54. For the plant in Nimtofte are no details on the electricity production available; this plant is operated “whenever there is some time left”, i.e. sporadically, according to the operator.

Figure 7-1 190kW Bayern Engine, BGA Stimmer

The vast majority of the operators (82%) sell all of the produced electricity to the local electricity grid in order to maximise the financial benefits, as buying electricity is generally cheaper than the sales price realised for the produced electricity. Only one site in Austria and one plant in Germany use the produced electricity for parasitic requirements. On average the AD plants require 1-8% of the produced electricity for parasitic requirements depending on the type of AD system. Thermophilic systems typically require more electricity to operate than mesophilic systems. The bonus payment for kWh of electricity sold ranges from currently 17.5€c in Austria to 28€c in Italy. According to plant operators in Germany and Austria a minimum bonus payment of 16-17€c is required to make the plant operation financially viable. In Germany the average payment for each kWh was between 19 and 24€c. In Austria the payment is fixed at 14.5€c plus a small extra bonus, which is reviewed annually. In 2009 the extra bonus was 4€c/kWh in 2010 it was reduced to 3€c/kWh. According to one operator the current payment of 17.5€c/kWh is the absolute minimum to make the plants financially viable and the comparatively low bonus payments are the reason why AD development in Austria has practically halted in the last 12 months. Heat

54 Based on 90% CHP engine availability


Depending on the AD system type, 10-20% of the produced thermal energy is required for the AD process; the remainder is available for heating use elsewhere. Only 5 of the 19 visited plants utilise the maximum amount of heat available. Due to the legal requirement of AD plants to utilise the produced heat, all three plants in upper Austria use the heat generated. Two plants use the heat for woodchip and grain drying, one plant transfers the heat to the adjacent biomass burner. One plant in Germany also uses a large amount of the produced heat for woodchip heating, the remainder is used for farm buildings and engine cooling. The only plant connected to a district heating network is the plant in Foulum, Denmark. The new AD plant in Brunsbo, Sweden has no heating connection yet, but did state that they may potentially be able to supply a local village through a district heating network. Most other farms only recover heat for engine cooling purposes and during winter for the farm living accommodation and outbuildings, such as stables. BGA Erdmann supplies the local lido with heat at no cost. The utilisation of the heat in Germany is paid with an extra bonus of 2€c/kWh.

Figure 7-2 Woodchip drying, Utzenaich

Biofuel Both plants visited in Sweden upgrade the produced biogas to biomethane for use as a vehicle fuel. The AD plant in Brunsbo, Skaraborg is currently being commissioned. The plant is designed to treat manure (95%) and a small percentage of potato wastes. The produced biomethane is expected to be in the region of 130,000 – 208,000m3/a, providing as much fuel55 for vehicles. Although there is extensive use of biomethane in the southwest of Sweden, there is no immediate market end-user in the local area. The gas will therefore be transported to the greater Stockholm area for end-use. The second AD plant visited in Sweden, Wrams Gunnarstorp, also upgrades the produced biogas. Here the upgraded biomethane is injected into the local gas grid. The calorific value of the upgraded biomethane is below the minimum calorific value (CV) requirements of the Swedish Gas Injection regulations. Therefore it has to be enriched with a small % of propane prior to injection into the local gas grid. On average 63,000m3 of biomethane are injected into the local gas grid every day. Operational Issues In general the plant operators were content with the AD technology and the operation of the plants. Only a few operational issues were reported, mainly of mechanical nature. Problems with the feeding system were reported. The solid feedstock (energy crops) is usually fed into a container from where the feed is transferred into the digester via screw conveyor. Due to the abrasive nature of the energy crops the screw conveyor is prone to accelerated wear. One plant in Austria had a concrete feed container in which the abrasion of the top layer was clearly visible. The other main problem related to broken mixing paddles, although the problem could not be pinpointed to a specific type of AD system. The AD technology supplier UTS has integrated service shafts in the reactors, allowing direct access to the paddles and avoiding the need of having to empty the digester tank for repair.

55 1Nm3 of methane is equivalent to 1l of diesel


Frequent comments were made about the importance of sufficiently sized pipe diameters to prevent blockages and the use of stainless steel pipes to prevent accelerated leakages.

Plants accepting chicken or turkey manure were reported to build up a layer of sand deposits within the digesters. Consequently, these have to be emptied on a regular basis, possibly every 2-3 years. Biological process problems were either not, or not knowingly, encountered. Most farmers reported they adjusted the feedstock tonnage when the gas yield production dropped below a certain level. The evaluation of the provided plant performance data suggests that sub-optimal biological activity is occurring at some plants, but it was noticed that farmers were generally happy to operate at a steady biogas production levels rather than having to spend extra time on trying to reach optimum gas yields. Of most concern to them was that the CHP engines were running at maximum efficiency. Many of the operators reported annual CHP engine hours of 8,600 and more.

Figure 7-3 Energy crop feeding system, BGA PIRo, Dorfen

Emission Control on site Plant emission control regimes varied from country to country, depending on the national legislative requirements. In Germany, plants with a thermal firing rate of <1MW are exempt from the German Emission Control Regulations. Three of the five plants visited in Germany therefore had no gas flare and two of these plants were not even equipped with a stand-by CHP engine. Instead, farmers reported that they vent the biogas into the air uncontrolled, whilst carrying out CHP engine maintenance, thus resulting in increased greenhouse gas emissions. In Austria, Denmark and Sweden the installation of a gas flare is compulsory and all plants visited in these countries had gas flares installed. Many of the plants visited in all four countries had uncovered digestate storage, thus also emitting residual methane uncontrolled into the atmosphere. The effect of this emissions source is currently of concern and under review in Germany. Biofilters were only installed at 2 of the visited sites. The installation of a biofilter is not compulsory in any of the targeted countries; the requirement generally depends on the location of the site in relation to nearby housing. None of the sites visited reported any odour complaints in the past. Finally, in Germany and Austria leak proof silos have to be installed for the capture of any leachate water from the feedstock silos in accordance with the German Groundwater Regulations.


Figure 7-4 Digestate storage, Utzenaich

Figure 7-5 Silo storage construction, Piro, Dorfen

Many plants were operated by a group of farmers, on a cooperative or community basis, with each contributing feedstocks (some grains, some slurries etc) and then making use of the digestate between them and sharing in the costs and profits. This may offer a good sustainable concept that minimises costs and risks and could be applied elsewhere. There was also some anecdotal evidence to suggest that some farmers in Germany were planning to give up livestock farming (when the current milk subsidy ends) to concentrate instead on AD/biogas/power production, using feedstocks from neighbouring farms.


8.0 KEY FINDINGS

The key findings of this study are summarised in the following sections. Feedstock and energy production

o In most countries the vast majority of plant operators (c.80%) treat a mix of feedstocks and only very few plant operators (c.5%) treat exclusively farm animal wastes. Mono feedstocks are rare and often manure and slurries are co-digested with a mixture of other feedstocks, as the digestion of manures and slurries on their own may not generate high biogas volumes (due the high water content of these feedstocks) and the biogas yield may be accelerated by the addition of carbon sources contained in energy crops and food waste. No agricultural AD plant was found to treat paper and cardboard;

o Increased biogas yields can be achieved with agricultural/ energy crops and food and green wastes rather than with traditional farm wastes, such as manures and slurries. The results showed that AD plants treating a significant proportion of energy crops and food waste have a higher electricity production rate per tonne of waste feedstock (168-418 kWh/t) than plants treating manure and or slurries only (~75kWh/t), or plants that only include a small percentage of energy crops. To ensure that manures and slurries continue to be treated by AD and do not get dropped in favour of feedstock producing more biogas the German government introduced another bonus, offering 4c€/kWh, if at least 30% of the feedstock is made up of manures and/ or slurries;

o Insufficient feedstock characteristics were available to evaluate the actual biogas production rate or electricity generation per tonne of waste feedstock. Instead, theoretical values were used to evaluate the individual plant performances. In the majority of cases the actual plant performance matched the calculated theoretical values. Hence, the values provided in literature appear to provide reliable guidance on the energy potential of specific feedstocks;

o The case studies showed that plant operation has an impact on the achievable biogas production. Insufficient feedstock preparation, insufficient hydraulic residence times, excessive organic loads, and poor mixing can all result in sub-optimal plant performance;

o Most farm-scale plants have a feedstock capacity between 5 and 20ktpa in the low energy engine range of 0.15-0.4MW. The digestate output tonnages in this energy range start from 3,000t/year treating energy crops to 100,000 tonnes, when the plant only operates on farm manures or slurries.

Waste Management Licensing Exemptions in visited countries o Germany: Agricultural waste (slurries, manures and plant wastes) is not classed as

waste and is therefore exempt from any permitting requirements. However, if this waste is used specifically for biogas production it turns into waste and therefore falls under the national permitting regulations, the 4. Bundesimmissionsschutz-gesetz (4. BImschG). The type of permit required depends on the plant throughput. Exempt from BImschG are plants with a thermal firing capacity of <1MW (equal to 350-380kWel), a daily tonnage throughput of <10t and a storage capacity of <2,500m3. All other plants have to be approved under the 4. BImschG. This includes the use of digestate under the national waste treatment regulations (Kreislaufwirtschafts- und Abfallgesetz) and especially the biowaste regulations (Bioabfallgesetz), if the substrate is classed as a waste. Digestates classed as fertilizers must be used in accordance with the national fertilizer regulations (Duengemittelgesetz).


o Austria: Biogas plants in Austria are regulated via the construction law (Baugesetz), and possibly also under the national waste regulations (Abfallgesetz). Agricultural biogas plants generally do not require a permit under the waste treatment law, if the feedstock comprises of farm wastes such as slurries, manures and plant wastes/ silages and if they are solely derived from an agricultural or forest business. If, e.g. source-segregated biowaste is added to the feedstock the plant will have to be permitted under the waste treatment regulations. Additionally there are a number of national guidelines for the construction and operation of biogas plants, which have to be followed, although they are not as binding as the laws.

o Italy: AD Plants up to 250kW do not require construction permits. Plants above this

limit require single authorisation (Autorizzazione Unica), which is issued by the relevant local authority. While the Single Authorisation regulations should be based on national guidelines, such guidelines have not yet been published, meaning that many local authorities have produced their own regulations, which differ one from the other. In Italy agricultural by-products such as slurries, manures, and energy crops are not classed as waste and are therefore not subject to waste regulations. Consequently, most counties also do not consider the digestate to be waste and thus, the product does not fall under any permitting regulations. However, some counties have taken a different, more restrictive approach, with regards to the use of the digestate. Currently there is a significant degree of uncertainty and confusion still present in Italy as to date no uniform national or indeed European regulations have been implemented for the use of digestate.

o Denmark: All AD plants treating less than 30t/d (11,000t/a) of agricultural animal

wastes or other organic wastes are exempt from waste treatment regulations. Plants exceeding this limit have to apply for a Kapitel 5 godkendelse – Miljøgodkendelse (Environmental Permit). The details of this permit are extensive and no further details were made available during the site visits. It is understood that digestate has to be stored for a period of 9 months prior to use on agricultural land and that there are restricted spreading times due to the national fertilizer regulations.

o Sweden: AD plants in Sweden are regulated by a vast set of rules. These have been

reported to be complicated. Consequently, the Swedish government, local municipalities and institutions are currently in the process of reviewing the regulations with the aim to simplify the regulations on a national level. In the meantime the most important and comprehensive set of rules and exemptions are covered by the Miljökonsekvensbeskrivning (MKB), the Environmental Impact Description. Within the MKB, only AD plants with a biogas production of <150,000m3/a (equivalent to 1.5-8t/d or 550-3,000t/a depending on the feedstock) are exempt from permitting; all other plants are obliged to comply with the requirements of the MKB, which covers all environmental aspects, including emissions to land, water and air. Details of the MKB were not available.

AD Technology Development o The most common form of feedstock storage continue to be tanks for slurries and flat

bunkers or open silos for manures and energy crops; o Solid material is generally shredded prior to transferring it to the digester in order to

achieve increased biodegradation and to avoid blockages in pumps and pipes. Liquid feedstock is sometimes pre-treated in a hydrolysation step, although no clear trend towards this step was detected;

o Liquid feed is generally pumped into the digester; only few systems use feed by gravity. The preferred methods for solid feed appear to be containers with integrated


walking floor and screw conveyor and combined dosing systems (combination of shredder, weighing and dosage system);

o The most common AD technology found in agriculture is based on wet, mesophilic digestion due to the generally low percentage dry solids content of the feedstocks and the relative insensitivity of mesophilic bacteria to variations in the feedstock. Only a few plants treating feedstocks with high dry solid contents are operated in thermophilic mode. Thermophilic bacteria populations are reported to be less diverse and more sensitive towards feedstock changes; importantly thermophillic plants have a higher parasitic heat demand and will therefore likely export less energy;

o No clear trend was observed on the preferred type of digester building material (steel or concrete) or on the type of digester heating (e.g. internal or external);

o On several occasions use was made of sloping surfaces by building the digester reactor partly into the hillside. This way the reactor loses less heat and thus saves energy;

o All digesters were equipped with some form of mixing system. The most common mixing system used was a submerged electrically or hydraulically driven paddle located in the centre of the tank;

o The design of most AD plants that were visited was based on long residence times within the digester. This is due to the higher gas yields that can be achieved with prolonged residence times. The plant design is laid out for increased energy production as opposed to increased feedstock treatment;

o Some countries (e.g. Austria, Germany) introduced a graded bonus system, which offers the highest bonus for the smallest plant category. As a result the plant capacity of most new plants is below 500kW. In other countries, where the same bonuses are paid independent of the plant size (e.g. Belgium, Netherlands) larger AD plants are generally built, often in connection with a dedicated district heating scheme;

o For a limited period Germany provided an extra bonus on using innovative technologies, which included dry anaerobic digestion. This led to a number of dry digestion plants being built. The design of the majority of those plants is similar to wet digesters, with the main difference being a slightly increased dry solids content of the waste feed. The waste is fed via a screw conveyor from the feed container directly into the digester. Due to the biodegradation process the digested material has a lower solids concentration than the feedstock and can therefore be kept in a pumpable condition. Only few operators installed actual dry AD systems based on plug-flow;

o Most of the visited plants had gas storage integrated into the digester or post digester with a double membrane roof. Only few sites had external gas storage holders. None of the visited sites did any gas cleaning prior to its use in the CHP engines;

o Small AD plants in Germany are exempt from the national emission pollution prevention regulations, which resulted in many plants not having installed a gas flare. Instead the plants are equipped with a connection flange for the installation of mobile gas flares during maintenance or emergency periods;

o The individual national planning requirements clearly have an impact on the design of the AD plants but also on the development of renewable energy utilisation. In Germany the introduction of a heat bonus has increased the percentage of heat utilisation from AD plants to over 50%.

Regulatory and fiscal drivers for AD development o Both, planning permission requirements and available bonus schemes had an

influence on the actual AD technology development. The vast majority of the operators (82%) sell all of the produced electricity to the local electricity grid in order to maximise the financial benefits. It was also noted that some farmers abandoned their cattle breed in favour of AD treatment due to the higher subsidies paid for energy generation;


o Farm wastes like animal manure and slurry are increasingly mixed with energy crops such as maize- and grass silage, or other plant wastes. This is partly a consequence of the governmental incentives introduced in some countries to promote the use of energy crops, but is also partly due to the increased gas yield achievable with these crops compared to manure and slurries;

o Despite lower achievable gas yields the majority of German farmers mix at least 30% of farm manures or slurries into the feedstock in order to qualify for the “slurry bonus” of 4c€/kWh;

o Due to introduced heat utilisation incentives most plants now utilise at least some of the heat, e.g. for digester heating, office and farmhouse heating, and outbuildings such as stables;

o In Upper Austria planning permission will only be granted, if a heat utilisation concept has been submitted; the heat was found to be mainly utilised for grain or woodchip drying;

o For a long period Sweden offered substantial incentives and benefits for the production and the use of biomethane as vehicle fuel. Consequently, Sweden is the market leader of biomethane fuel production and many farmers upgrade the fuel to biomethane instead of generating heat and electricity;

o All of the visited plants in Germany and Austria were exempt from any permitting requirements due to the agricultural classification of the plant feedstock;

o The air emission exemption available to small scale AD plants in Germany resulted in the lack of gas flares at many farm-scale plants leading to uncontrolled methane emissions caused by farmers during periodic CHP plant maintenance.

Emissions o Uncontrolled methane emissions are caused by the lack of gas flares (see above) and

open digestate storage tanks, as coverage of these is generally not legally controlled. The effect of this source of emissions is currently increasingly under review and discussion in Germany;

o Biofilters were only installed at 2 of 19 visited sites. However, no odour complaints were reported at any of the sites;

o Silo storage has to comply with strict building regulations to prevent leakage into the groundwater system;

o The use of the produced digestate as organic fertiliser instead of artificial fertilisers reduces the environmental impact of the farm;

o The production of renewable energy greatly reduces the carbon footprint of an AD plant, especially when local feedstocks are used.

Operational observations

o Some of the visited plants were operated as co-operative of 3 or more farmers. The farmers all contribute their feedstocks to the plant and utilise the produced digestate on their own fields, thus effectively providing a self-sufficient closed system.

o In general the plant operators were content with the AD technology and the operation of the plants. Only few operational issues were reported. These were mainly of mechanical nature. Problems with the feeding system and broken mixing paddles were mostly reported.

o No issues were reported with regards to the biological operation of the plant. However, the evaluation of the case study data showed that some plants appear to operate under sub-optimal plant conditions, e.g. the actual gas yield was well below the theoretical gas yield of the feedstock. The most likely cause for this is reduced bacteria activity caused by e.g. excessive organic loading rates, pH variations, or


insufficient temperature control. Consequently the material is only partly degraded, resulting in reduced electricity production of the material and continued methane emission from the digestate product during storage or application to land.


9.0 CONCLUSIONS

In relation to Defra‟s key objectives, the following conclusions can be drawn: Use of targeted waste feedstocks in Europe

o Governmental incentives have shifted the focus of AD treatment from “farm waste treatment” to “energy production”, i.e. AD plants are not operated as a form of waste treatment but as a form of power supplier that can be turned into a viable business. As a result most operators add energy-rich feedstocks, such as maize and grass silage to the wastes produced on farm, such as manures and slurries. The use of mono-feedstocks was very rare;

o Food wastes are generally not treated in small-scale plants due to the mechanical pre-treatment requirements and the associated additional costs;

o Manures and slurries require the installation of large digester volumes in order to produce sufficient gas to make the plant economically viable;

o Energy-crops provide a carbon source that accelerates the digestion process of manures and slurries when added to the feedstock. They also produce up to 7 times more biogas per tonne input than farm slurries and around 4 times more biogas than farm manures. Considering the shift in the purpose of on-farm AD treatment in Europe since the introduction of renewable energy bonus schemes, it can be expected that the same development will take place in the UK, leading to the increased treatment of energy crops in agricultural AD treatment plants.

AD performance and AD development

o The priority of agricultural AD plant operators was found to lie on plant reliability rather than on process optimisation for specific feedstocks. As a result, AD development seemed to have focused on the improvement of existing process technologies, e.g. by developing improved material transport through the system and by designing better access to vulnerable mechanical parts, rather than on the development of newer treatment options, such as thermophilic plug-flow treatment;.

o Consequently, very little operational problems had been reported by the operators of the visited sites. Mechanical failures were generally limited to abrasion on feed screw conveyors, pipe blockages and occasional breakage of stirring paddles;

o Lower than average gas yields pointed to some of the visited plants being operated at sub-optimal biological process conditions. However, these were either not obvious to the operators or were accepted on the basis that the farmers simply did not have the additional time for process control and optimisation. Underperformances experienced at agricultural AD treatment plants are therefore not deemed to be caused by certain AD technology designs but rather by a certain degree of neglect of the operators.

Influence of governmental incentives on AD development

o A minimum level of capital funding is required to encourage the farmers to install AD plants;

o Graded bonus payments for a range of plant sizes were found to result in most new plants being installed matching the range of the highest graded bonus payment rather than e.g. the available feedstock tonnage. Where bonus payments were not graded (e.g. Belgium, Netherlands) the focus shifted from “commercial gain” to “best renewable energy option”;


o The vast majority of operators follow the option with the highest achievable bonus payment independent of actual local circumstances, such as available feedstock, best potential for energy utilisation on site/ in the local area, or best suitable treatment technology.

o High bonus incentives may encourage farmers to abandon livestock farming for the more commercially attractive “energy” farming;

o Heat is generally only used in countries where its utilisation is compulsory (Austria) or where a minimum bonus (Germany) is available;

o These examples show that governmental incentives can heavily influence not only the plant size and choice of technology, but also the type of feedstock that is being treated;

o The examples also showed that incentives focusing only on one end-product may prevent the development of certain technologies; thus incentives for both, technologies and feedstocks, have to be carefully considered prior to their implementation.

Influence of permitting systems on AD development

o Plant operators were found to base the decision of the design plant size and the feedstock to be treated on realisable bonus payments rather than on regulatory framework requirements, such as environmental permits;

o Independent of the actual location, AD plants are generally built to the minimum permitting standard required. Fugitive emissions were not measured at any of the sites visited in the various countries and thus no conclusions could be drawn from the relationship between the size of the plant and the emission levels. It was clear however, that relaxed regulations tend to promote unawareness or even carelessness with regards to emission control;

o Another site observation in Germany and Austria was that the extensive and costly measures required for leak proofing silo storage bunkers did not prevent any of the farmers from installing an AD plant for the (part-) treatment of energy crops. The reduction of the bonus payment in Austria however appears to have stopped, or at least significantly slowed down, the planning applications for new AD plants in 2010. This indicates that pollution prevention control measures appear to have less influence on the decision making process than available bonus schemes.


10.0 REFERENCES

Dti, May 2007: Meeting the energy challenge

Jeremy Eppel, defra, 2007: Presentation on UK experience on using AD in agriculture, Buenos Aires.

1http://www.biogas-info.co.uk/index.php/ad-map

Environment Agency website, “Our view on Anaerobic Digestion”, accessed on 14 June 2010, http://www.environment-agency.gov.uk/business/sectors/32601.aspx

Accelerating the Uptake of Anaerobic Digestion in England: an Implementation Plan, Defra, March 2010.

Universitaet Rostock/ Institut fuer Energetik und Umwelt, Jan 2007: Biogaserzeugung durch Trockenvergärung von organischen Rückständen, Nebenprodukten und Abfällen aus der Landwirtschaft

Encrop, 2008: Leitfaden Biogas

Bayrische Landesanstalt fuer Landwirtschaft, jan 2010: Biogas-Pilotanlagen Bayern Messergebnisse

Wiemer, K., Kern, M., 1996: Technisch-wirtschaftliche Umsetzung von Ressourcen- und TA-Siedlungsabfallbezogenen Abfallwirtschaftskonzepten im regionalen Verbund

WRAP 2010: Quality Protocol Anaerobic Digestion - The quality protocol for the production and use of quality outputs from anaerobic digestion of source-segregated biodegradable waste

PAS110:2008: Specification for whole digestate, separated liquor and separated fibre derived from the anaerobic digestion of source-segregated biodegradable materials Universitaet Rostock und Institut fuer Energetik und Umwelt, 2007: Biogaserzeugung durch Trockenvergärung von organischen Rückständen, Nebenprodukten und Abfällen aus der Landwirtschaft; Abschnitt 2 Amon et al. 2004, Kryvoruchko 2004, DBU 2006 ALFAM Modell: Søgaard 2002, DBU 2006

Sven Gaertner: Sep, 2009: Tagungsband: Biogas in der Landwirtschaft-Stand und Perspektiven („Biogas in agriculture – actual situation and perspectives“)

Sven Gaertner, 2009: Wie oekologisch ist Biogas? (How ecological is biogas?) Guelzower Fachgespraeche, Band 32: Tagungsband „Biogas in der Landwirtschaft. Stand und Perspektiven“

Eurobserv‟er – etat des energiesrenouveable en Europe – Edition 2009

http://www.biogas-info.co.uk/index.php/ad-map

http://www.environment-agency.gov.uk/business/sectors/32601.aspx


European Union Directive 2003/30/EC


1 www.biogas.klimaaktiv.at

Agrobiogas, 2006: Deliverable 1: Update on the ongoing AD research activities and results

Claudius da Costa Gomez et al, 2004: European Biogas Conference, Northern Ireland: Current Practice and Progress in the adoption of anaerobic digestion in the European Union

Source Czech Biogas Association

www.biogas.dk

Annelli Petersson, 2008: Biogas from an international Perspective; Swedish gas Centre

W. Bischofsberger, et al, 2007: Anaerobtechnik

Landwirtschaftskammer NRW, 2009: Biogas in Nordrhein Westfalen

Bayrische Landesanstalt fuer Landwirtschaft, 2006: Biogasanlagen in Bayern

EU funds for renewable energy sources: KEOP 2009/4.4.0 (Heat and/or electricity production from renewable sources) and KEOP 2009/4.2.0 (Local heat and cooling supply from renewable sources).

Sergio Piccinini, „Biogas: Situazione e Prospettive‟, CRPA, Verona Bioenergy EXPO, Feb 2010.

EREC, „Portugal: Renewable Energy Policy Review‟, 2009.

Presentation by Ana Silveira at International 8th ASA Waste Days: MBT and anaerobic digestion in Portugal

Estratégia Nacional para a Redução dos Resíduos Urbanos Biodegradáveis destinados aos Aterros



Mundoenergia, „España genera biogás agroindustrial en 8.000 millones de m3/año, 15/07/2009.



http://www.biogas.klimaaktiv.at/

http://www.biogas.dk/


http://www.mundoenergia.com/noticias/renovables/espana-genera-biogas-agroindustrial-en-8000-millones-de-m3ano-200907152507/


Annelli Persson, Swedish Gas Centre

German Biomass Research Centre, 2009: Monitoring zur Wirkung des EEG auf die Entwicklung der Stromerzeugung aus Biomasse (Electricity production from Biomass)

Jan Postel et al, Umweltbundesamt, Dec. 2009: Stand der Technik beim Bau und Betrieb von Biogasanalgen (State of the Art for the design and operation of biogas plants)

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APPENDIX A:

Map of Biogas Sources in Europe

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APPENDIX B: Available AD Plant Information by Country

In electronic copy of report

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APPENDIX C: AD Plant Data Comparator Matrix

In electronic copy of report

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APPENDIX D: Overview of Scoring System for Key Performance Indicators

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1 KPI – DATA AVAILABILITY Data availability - Scores:

Data include

a) insufficient data available 0

b) throughput, feedstock, and energy output only 1

c) additional details on AD system (e.g. wet/dry 1 or 2 stages) 2

d) details for b and c, but also on performance (%DS, %VS destr., gas production) 3

e) details for b, c and d but also info on digestate production and emissions 4

2 KPI – FEEDSTOCK

0

1

2

3

4

b) feedstock not on Defra list (e.g. not manure, slurry, green waste, food waste, paper & card)

c) mix of feedstocks partly matching Defra list

d) mono- or mix of feedstocks matching Defra list

e) mono-or mix of feedstocks matching Defra list, including tonnage details

Data include:

Scores:

a) no feedstock details available

3 KPI – AD SYSTEM DETAILS AD System- Scores:

Data include:

a) no AD system details available 0

b) only technology provider known 1

c) technology provider and AD type (e.g. wet/dry, 1- or 2-stages) known 2

d) data under c plus organic load and/ or residence time available 3

e) data under c+d plus details on dewatering, digestate and gas storage available 4

4 KPI – PLANT PERFORMANCE Plant Performance - Scores:

Data include:

a) no AD performance details available 0

b) only limited data provided, e.g. biogas/ energy production rate only 1

c) details on biogas production/tinput or /tVS, reactor volume, and biogas quality 2

d) data under c plus robustness of system, operating temp., and %DS 3

e) data under c+d plus details on TS/VS destruction rates, and pathogen reduction 4

- continued next page -

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5 ENERGY DATA

0

1

2

3

4

b) only CHP engine size available

c) details on electricity produced available

d) data under c plus details on heat production and heat use available

e) data under c+d plus details on parasitic plant requirements

Scores:

Data include:

a) no energy output details available

6 OTHER TECHNICAL CONSIDERATIONS OTC - Scores:

Data include:

a) no other details available 0

b) only plant age and operational status known 1

c) details on digestate production and digestate end-use available 2

d) data under c plus details on historic operational issues/ downtimes available 3

e) data under c+d plus details on technical risks available 4 7 EMISSIONS Emissions - Scores:

Data include:

a) no emission details available 0

b) basic details of emission treatment methods (e.g. flare, biofilter) available 1

c) volume of process water and emissions to air available 2

d) data under c plus details on use of digestate/ process water available 3

e) data under c+d plus details on digestate quality and/or requirement of chemicals available 4

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APPENDIX E: Site Visit Protocol Template

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Name & Address of operator

Date:

Duration of site visit:

Generic data

Technology Provider:

Start of operation:

Feedstock

Feedstock(s): Size of farmland (ha):

No of animals:

AD system

No of digesters: 1stage 2 stages

Digestate storage (m3): wet dry

Gas storage (m3): mesophilic thermophilic

Technical data

Feedstock DS VS

%

kg/t

Produced digestate t/a DS VS

%

kg/t

Operational temperature °C (stage 1/stage 2):

Pasteurisation?

Digester volume m3:

Feed volume t/w:

Residence time d:

organic load kg VS/m3*d:

Effective operational time (hours / %):

Biogas production

Nm3/a:

Nm3/t:

CH4-content %:

CHP engine name:

No of engines:

Size kW:

Average electricity produced kwh/a kWh/a

kwh/t kwh/t

electrical efficiency % %

CHP use h/a Parasitic thermal requirements: kwh/t

Total energy recovery efficiency % Total heat surplus:

Heat use:

Parasitic electrical requirements kwh/t

Electricity surplus kwh/a

Other information

Environmental permitting route:

Capex (£/€):

Opex (%):

Subsidies/ funding received (e.g. feed-in tariffs):

heat efficiency:

Total-N

Total-N

Electricity production Heat production

Average :

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APPENDIX F: Case Studies

- Glossary of terms

- Austria (3) - Denmark (7) - Germany (5)

-Italy (2) - Sweden (2)

-Note: Additional site photographs in electronic copy of the report-

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CASE STUDIES - GLOSSARY OF TERMS

Abbreviation

DS dry solids content

VS volatile solids content

Total-N Total Nitrogen

Nm3 Normal cubic metre

(0°C and atmospheric pressure)

CH4 methane

CHP Combined heat and power engine

kW kilo watts

kWh kilo watt hours

a annum/ year

t tonne

h hour

capex capital expenditure

opex operational expenditure

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APPENDIX G: Relevant Environmental Permits and Exemptions of Visited Countries

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Country Name of Key

Environmental Permitting Regulations

Exemption for small scale

Anaerobic

Digestion (Y /N)

Environmental permit

for anaerobic digestion

(Y/N)

Qualifying Criteria for Exemption/Permit from Environmental Permitting Regs (or equivalent national legislation) e.g. waste

types, throughput, biogas burner size, digestate retention time. (web-link to relevant website)

Other aspects of

environmental regulatory

regime identified in

study

Germany National construction law “Bundesimmissionsschutzgesetz” (BImschG) Bioabfallverordnung (BioabfV) Kreislaufwirtschafts- und Abfallgesetz (KrW/AbfG)

Y Y Has to comply with generic requirements of the national construction law; http://www.baurecht.de/baugesetzbuch.html Plants with a thermal firing rate of <1MW, <10t/d throughput and with an end storage capacity of <2,500m

3 are exempt from these

regulations; http://www.bmu.de/files/pdfs/allgemein/application/pdf/bimschg_071023.pdf -Manure/ slurries are classed as waste when used in biogas plants with the intent to produce renewable energy; http://www.bmu.de/files/pdfs/allgemein/application/pdf/bioabfv_engl.pdf - abattoir waste has to be treated in line with EU Animal By Products Regulation (1774/2002/EC) http://www.bmu.de/files/pdfs/allgemein/application/pdf/promoting.pdf

German Groundwater Regulations require the installation of leak proof silos and the capture of any leachate water from these silos

Austria National building law

Y Y Exempt, if waste is purely agricultural; http://www.baurecht.at/index.asp?r=SOF Sewage sludge is banned as feedstock; abattoir waste has to be treated in line with EU Animal By Products Regulation (1774/2002/EC)

in Upper Austria it is required to implement a heat recovery plan; without such a plan, planning permission

http://www.baurecht.de/baugesetzbuch.html

http://www.bmu.de/files/pdfs/allgemein/application/pdf/bimschg_071023.pdf

http://www.bmu.de/files/pdfs/allgemein/application/pdf/bimschg_071023.pdf

http://www.bmu.de/files/pdfs/allgemein/application/pdf/bioabfv_engl.pdf

http://www.bmu.de/files/pdfs/allgemein/application/pdf/bioabfv_engl.pdf

http://www.bmu.de/files/pdfs/allgemein/application/pdf/promoting.pdf

http://www.baurecht.at/index.asp?r=SOF

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will not be granted

Italy DLvo 387/03 decree

Y Y/N Requirements vary for different counties

Denmark Bekendtgørelse om godkendelse af listevirksomhed nr. 1640 af 13. December 2006. (BEK No. 1640 of 13 December 2006 (Approval Order)

Miljøbeskyttelsesloven (Environmental Protection Act)

Affaldsbekendtgørelsen (Waste Order) Planning zone permit and building permit - Byggetilladelse

Y Y Kapitel 5 godkendelse – Miljøgodkendelse - You need to apply for this if you process animal manure, and your biogas plant has a capacity of input of animal waste or organic waste or abattoir waste of 30tonnes or more per day. You are exempt if input is less than 30 tonnes per day

The conditions on the storage of sewage sludge is that no splashes or spillage on the tank edge, and the manure tank has to be covered with layer of clean odour absorbing material to prevent odours between emptying and filling.

Sweden Chapter 6 of the Environmental Code - Miljökonsekvensbeskrivning (MKB).

Y Y Exemption if produce<150,000cubic meters biogas on the farm. No information

http://147.29.40.90/_LINK_0/0%26ACCN/B20060164005

http://147.29.40.90/_LINK_0/0%26ACCN/B20060164005

http://147.29.40.90/_LINK_0/0%26ACCN/B20060164005

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european experience of small-scale and on-farm ad

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