The Danish biogas sector -

Biogas technology & Policies & Way forward

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By Associate Prof. PhD. Rikke Lybæk (rbl@ruc.dk)

University of Roskilde, Denmark, Institute of Human & Technology

Agenda

Introduction to biogas in Denmark • Energy production & targets

• Energy outputs

• Plant location, ownership & capacity

• Typical Farm Biogas plant

• Typical Centralized Biogas plant

• The biogas process

The use of manure on farmland in Denmark

Barriers for implementing biogas in Denmark

New stakeholder actions (to overcome barriers)

Newest development in biogas ‘governance’

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Introduction to biogas in Denmark

Energy:

- Contributes to 4.2 PJ or 0.5 % of the Danish energy consumption (≈ 750 PJ).

- 60 % produced on biogas plants, and the remaining on waste water treatment plants & landfill sites.

- The estimated total available resources for biogas production could provide 40 PJ

of energy (10 *more).

- This would correspond to 5 % of the total energy consumption in Denmark.

- Even higher percentage in the future due to lower total energy consumption, thus

down by 200 PJ to 550 PJ before 2050.

Targets:

- ’Green Growth Strategy’ (2009) → Digest 50 % of the manure before 2020 = 20 PJ.

- Would require the implementation of appx. 50 new Centralized biogas plants.

- Overall energy & transport target in DK before 2050 = zero carbon emissions !

- Energy production & targets -

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- Energy outputs -

= Electricity

= Heat

= Lost

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Centralized Biogas plants:

Electricity: - Distributed on the public grid. Heat: - Used to heat up reactor tanks. - Distributed on a small scale district heating network within the local community, or - Distributed on a larger district heating network in the region. Biogas: - Few new plants upgrade to Ngas & distribute biogas on the gas network; used in small heat boilers in households for space heating & in industry. - Limited use for transport purposes, but growing.

Farm Biogas plants:

Electricity: - Distributed on the public grid. Heat: - Used to heat up reactor tanks, and - Livestock stables & farm-house etc. Biogas: - Limited biogas send to nearby Heat plants. - Limited biogas to CHP plants for prod. of electricity & district heating. - Two large Farm plants upgrade to Ngas and distribute on the national gas network.

CHP-production

------------------------------------

Ngas = Natural gas

CHP = Combined Heat & Power

- Plant location, ownership & capacity -

- 30 Centralized biogas plants (2-3 more in pipeline).

- Joint ownership between farmers & municipalities and now also farmers & energy companies. - Capacity of 100-1,200 m3 manure/day.

- 49 farm plants (2-3 more in pipeline). - Ownership by one single farmer. - Capacity of 10-300 m3 manure/day.

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- Typical Farm Biogas plant -

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Thorsø Farm plant, Black-smith plant

- Typical Centralized Biogas plant -

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Lemvig biogas plant

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Animal manure utilized for biogas production in Denmark:

-Manure from cow and pig stables widely utilized (e.g. 20 mill. pigs in DK). -Manure from poultry, mink and horses also utilized.

Depicturing the biogas-process:

- The biogas process -

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-Large trucks collect the manure from the farmers and transport it to the biogas plant. -Organic waste from industry e.g. are also collected & hygenized for 1 hours by 70 C. at the biogas plant before mix with manure.

-At the biogas plant the manure is pumped to the receiving unit below. -Dry matter content of manure are measured. -Then mixed with other types of org. wastes e.g. -Slaughterhouse, household & crop residues.

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-The manure are then pumped from the receiving unit to the pre-storage tanks of the Centralized biogas plant. -Mixed, stirred and slowly pre-heated.

-The manure is pumped to the reactor tanks, where it is heated to e.g. 40-55 degrees C., & -Methane (CH4,H2,CO2) developed = Biogas.

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-The biogas are now send to storage in a gas tank with 2-3 days of capacity. -From here it can be used for energy prod. on a constant basis.

-The biogas is mostly converted to energy as power & heat (CHP) in a motor/generator unit. -Few biogas plants utilize biogas for upgrading to Ngas standard yet.

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-The digested manure (digestate) are pumped to the manure storage tanks. -From here it is collected by trucks and returned to the farmers.

-The manure is stored in manure tanks at the individual farms, in covered manure tanks with 9 month capacity. -Later distributed on farm-land as valuable fertilizer.

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-Digested & non-digested manure is spread on farmland during crop season under certain conditions: temp, wind, rain etc. to avoid N-spill. -In Denmark 30 mill. T manure/year distributed on farmland; 7 % of this is digested (digestate).

-Crop yield increases by 10-20 % is documented. -By enhanced uptake of nitrogen (N) by crops. -The odor problems decrease when spreading digested manure (up to 30 % is measured). -Cost savings buying artificial fertilizer (CO2↓).

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In Denmark the following rules/conditions apply:

-Harmonie between nr. of livestock animals & available soil for distributing manure. -Danish agriculture provide their own fodder so land is available for distributing manure. -Rules of when & how to spread digested & non-digested manure are very strict. -Quality of water environment in Denmark improved significantly since this manure legislation came into force in the 1980’s. -Farmers join biogas plants to get high quality & cheap fertilizer through the digestate. -Farmers would like higher contents of N in manure (can happen with digested manure). -The current roof of applying 140-170 kg N/hectare farmland can thus be set aside, as -Total N-use-demand of digestate 58-68%; to the roof farmers use e.g. artificial fertilizer. -But digestate provide 10-20% higher N-use-potentials, due to the ammonium effect.

The use of manure on farmland in Denmark

Maize & silage

grass as animal

fodder

= Magic Manure !!

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-The new Solrød biogas plant co-digest manure, industrial waste & cast seaweed from the shore of Køge Bay. -This provide better digestate for use as fertilizer due to large N content in seaweed. -Thus, when using cast seaweed in Solrød biogas plant many benefits are obtained:

- High quality fertilizer & higher crop yield - No smelling beach from decay of seaweed - Lower N leakage from cast seaweed from beach to the water basin of Køge Bay - Production of renewable energy in Solrød municipality now substitutes fossil fuels

Example of ‘high quality fertilizer’

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Barriers for implementing biogas in Denmark Drawbacks/barriers:

• Lack of feedstock ‘boosting’ the gas yield:

-Slaughterhouse, fish residues, oily/protein rich food wastes, etc.

-Government roof on the utilization of energy crops (12 % in 2018) now 25 %.

• Local resistance towards Centralized biogas plants due to noise/dust from large

trucks transporting manure & Visual plant pollution.

• Low plant profitability, high techn. & operational costs, and long timeframe.

-Farmers want to make money (now!); not only to get valuable fertilizer.

• Lack of farmers engaging in promoting biogas:

-The financial crises hit the agricultural sector hard; no surplus £ & banks say no!

-Drivers in the deployment of biogas is now mainly energy companies, but

-Important still to include farmers to also focus on soil quality, nutrients, crops etc. -Not only on the amount of gas produced!

• New actions by Municipalities:

Support mapping of & utilization of new feedstock for biogas:

• Deep litter, straw from cereal production, biomass residues from municipal conservation of natural areas, organic waste from source separated household waste, blue biomass, etc.

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New stakeholder actions How to overcome barriers identified (Lybæk & Kjær, 2015)

Rikke Lybæk & Tyge Kjær (2015), ”Municipalities as facilitators, regulators and energy consumers: enhancing the dissemination of biogas

technology in Denmark”. International Journal of Sustainable Energy Planning and Management, Vol. 8, Nr. 2246-2929, 12.2015, p.17.

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Improve municipal energy planning:

• Municipal ‘heat planning’ should include supply of biogas in the future by e.g.: -Substitute Ngas with raw biogas in existing residential Ngas areas (who now uses Ngas in small heat boilers, but can switch to raw biogas). -Supply non-upgraded biogas to larger industries using Ngas using process heat.

• Require decentralized CHP plants to utilize raw biogas instead of Ngas in their boilers, through the ‘Energy Supply Law’.

• Facilitate and push for public transport to be fueled by biogas, to promote local vehicles to run on renewable energy and improve air quality.

Domestic Ngas boiler Stove using cooking gas Biogas bus

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• New actions by Energy Companies: Energy companies can support a market enhancement for biogas by:

• Today, energy companies set-up Centralized biogas plants jointly with farmers. • Before, only municipalities & farmers worked together on biogas. • Energy companies upgrade biogas to Ngas & distribute on the national Ngas network. • Provide more biogas for transportation purposes, which still is infant in Denmark. • E.ON. energy company in Copenhagen e.g. has 3 biogas fuel stations for transport,

but gas stations normally only provide conventional Ngas). • Sell certified bio-natural gas to Corporate Social Responsibility engaged companies. • Speed up mix of Ngas & raw biogas and distribute in cities as cooking-gas (up to 30 %

mix possible before the flame stop).

Danish ‘Nature Energy’ extend their Ngas pipelines

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Heat

Export power Heat farmhouse

Heat stables

CHP

Farm biogas plant Manure

storage

Heat farmhouse

Heat stables

Manure pipe

Export heat

Farm # 1 Farm # 2

“Neighbor-model”

- Makes it possible for smaller farm plants to connect to a large biogas plant.

- This means that the manure actually will be utilize for energy purposes & good

fertilizer produced.

• New actions by Farmers

Models of new types of cooperation between farmer, which could be

applied in Japan also (Lybæk, 2014)

Rikke Lybæk (2014), Development, Operation, and Future Prospects for Implementing Biogas Plants. In Use, Operation and

Maintenance of Renewable Energy Systems: Experiences and Future Approaches. red. / M.A. Sanz-Bobi (ed.). Vol. 111

Switzerland: Springer Publishing Company, 2014. s. 111-144 (Green Energy and Technology).

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Heat

Export power Heat farmhouse

Heat stables

Heat export

Heat used in: Nursing home

School Swimming pool Sports facility

CHP Farm biogas

plant

“Institutional-model”

- Provide a heat market for surplus heat on larger farm biogas plants, thus

- Increase the plant profitability.

- Help to fulfill renewable energy targets in local municipalities (national & EU targets).

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Manure storage

Large scale biogas plant Manure

storage

Manure storage

Manure storage

Manure storage

Manure storage

Export heat

CHP

Local community: District heating to

households

Exp

ort

po

wer

Manure pipes

”Star-model”

- Avoid heavy truck transportation of manure & associated environmental problems.

- Good mix of pig and cattle manure: better balance between phosphorus and

potassium (kalium).

Newest development in biogas ‘governance’

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Danish Energy Agency: -Provided higher FIT for biogas power to the grid ≈16.4 euro/GWh & 30 % const. grant. -Legalized biogas upgrading, distribution on the Ngas network, and biogas for transport. -(Still not legal to send raw biogas directly to e.g. industry). -Biogas is focus in Danish Governments: ‘Resource Strategy’ focusing on digesting organic household waste (not incinerate it), and -Recirculate nutrient, minerals & phosphor back to the soil (circular thinking).

The Government’s Resource Strategy, 2013 Promote Circular economy; only

possible with biogas technology

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Danish Natural Environment Agency: -Provide good examples of how to successfully implement biogas plants via visualizations’ using Graphic Information System (GIS), etc. -Publish literature about biogas planning within municipalities, and -Set up meetings / visits / workshops in municipalities to promote biogas, thus -Work to increase knowledge sharing between biogas stakeholders, farmers and others.

Challenge:

-Some Danish politicians skeptical of the high economic support to biogas compared to e.g. offshore wind energy (total 6,7 euro-cent/kWh vs. 3,3 euro-cent/kWh). -Do not fully understand the benefits of biogas, as an energy & environmental tech. -We need to disseminate the multiple benefits of biogas much more in the future !

Multiple benefits of the biogas technology

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Thank You