carbon accounting buildings | sue roaf
DESCRIPTION
TRANSCRIPT
Questions concerning theCarbon Accounting of Buildings
Heriot Watt Carbon Accounting Conference
11th March 2009
Sue Roaf Heriot Watt University& Robert Cohen, Technical Director, ESD Camco
See: www.carboncounting.co.uk
Stern review, Oct 2006
Source: Robert Cohen
Source: Ed Mazria of Mazria Inc. Odems Dzurec
We must decarbonise buildings
U.S. Energy Consumption Slide courtesy of Jesse Hensen, AIA, and Amy Hoagberg, CEM, Kyocera Solar & Don
Aitken
Building energy efficiency retrofit costs
£/tonne lifetime
CO2 100
0
200
300
Source: Robert Cohen
£0
£1,000
£2,000
£3,000
£4,000
£5,000
£6,000
£7,000
0 10 100 1000 0 10 100 1000
Carbon cost (£/tonne CO2)
Av
era
ge
ho
us
eh
old
co
st/
ye
ar
GasElectricity
Extreme refurbishment:
demand cut by two thirds
Cost of household energy in different worlds
Demand stays same
GasElectricity
2.713
2.9 4.6 2214 18 66
Source: Robert Cohen
Source: Robert Cohen
DIRECT EMISSIONS 34%
HOUSE ENERGY 19.5%
TRANSPORT ENERGY 14.5%
INDIRECT PRO RATA EMISSONS 51%
INDIRECT INFRASTRUCTURAL EMISSONS 15%
Carbon Dioxide Emissions will include: Probably the most ‘correct’ approach is to split the scores into four categories:- Direct and measurable- Indirect, pro-rated on the bases of purchases- Indirect, not pro-rated and attributed to the industrial sectors- Fixed infrastructure, not pro-rated and attributable to government policy.
Peter Harper, Centre for Alternative technology
• “The total set of greenhouse gas emissions caused directly and indirectly by an individual, organisation, event or product” Carbon Trust 2007
• Different types of carbon footprint:
1. Individual footprints
2. Organisational footprints
3. Event footprints
4. Product footprints
What is a Carbon Footprint?
Source: Robert Cohen
CO2 or CO2 equivalent
• Six gases are controlled under the Kyoto protocol. CO2e expresses greenhouse gas emissions as the amount of CO2
with the same global warming potential
Greenhouse Gas Global Warming Potential
Carbon dioxide (CO2) 1
Methane (CH4) 23
Nitrous oxide (N2O) 296
Sulphur Hexafluoride (SF6) 22,200
Perfluorocarbons (PFCs) 4,800 – 9,200
Hydrofluorocarbons (HFCs) 12 – 12,000
Source: Robert Cohen
Organisational carbon footprints
1. Define the boundaries (what you want to assess)– Organisational boundary
» Control» Equity share
– Operational boundary
2. Collect the data
3. Calculate emissions and convert GHGs to CO2e
Source: Robert Cohen
How to Calculate a Carbon Footprint
Emission producing activity within boundary
Assessment Boundary
Legend
Emission producing activity outside boundary
Assessment Boundary
Electricity Consumption
Business Travel
Waste Disposal
Company Owned/Leased Vehicles
Gas Consumption
Fire Extinguishers
Commuting
Deliveries
Refrigerant Gas Loss
Diesel Consumption
Source: Robert Cohen
Standards and protocols
• World Business Council for Sustainable Development/World Resources Institute (2004) - the Greenhouse Gas Protocol.
• ISO 14064 (2006) – Specification with guidance at the organisation level for quantification and reporting of greenhouse gas emissions and removals.
• Sources for emissions factors:
• Defra 2007. Guidelines to Defra’s greenhouse gas conversion factors for company reporting.
• WBCSD website. www.ghgprotocol.org• IPCC 2006. Guidelines for National Greenhouse Gas
Inventories. http://www.ipcc-nggip.iges.or.jp/public/2006gl/index.htm
Source: Robert Cohen
GHG Protocol – Strengths and WeaknessesStrengths
• Clear guidance on process of emissions accounting and reporting
•Sound principals defined: scope system can prevent double counting
•Tried, tested and developed over years with wide consultation
•Flexible approach – optional Scope 3 encourages reporting in steps
•Links to financial accountancy – helps carbon be seen as ‘assets’ and ‘liabilities’
•Provision of tools for calculation, with tiered approach
Weaknesses
• No requirement for verification
•Scope 3 is optional: limited advice on avoiding double counting
•No standard set of emission factors
•‘Well to wheel’ emissions not counted so difficult to report eg biofuel use
•Tiered approach so some assessments based on primary data others estimated
•Cross company comparisons difficult – no normalising and different scope
•No standards for base year recalculation
•No standard for materiality in verification
•No guidance given on credits/offsets
Source: Robert Cohen
Total energy use per m2 (primary or CO2 equivalent)
Lighting kWh/m2
Efficiency(W/m2)/100lx
Hoursof use
Effective hours/yr
Managementfactor
Vent rate(l/s)/ m2
Ventilation kWh/m2
Ventilation W/m2
EfficiencyW/(l/s)
Effective hours/yr
Managementfactor
Hoursof use
Otheruses
A
B B
D
F G H
C D
E F G HLight level
Lux
E
Lighting W/m2
C
Asset Control & management
Asset Control & management
The roots of building energy consumption
Source: Bill Bordass
Policy map: using EPCs and DECs to count direct carbon emissions from buildings
Sources of end use
Aspects of demand
Policies Solutions
Heating
Hot water
CoolingSolar shadingThermal mass
Ventilation PassiventLighting Lamp efficacy
Appliances/equipment
Low C designWash @ 30C
Low C IT
Product energy labelling (A to G)
Market Transformation
Imperfect control
Smart metersDisplays
Standby lossesBMS
Fiscally neutral carbon taxesEnergy pricesReverse tariffs
Inefficient behaviour
KnowledgeMotivationIncentives
Personal Carbon Allowances
CRC
Carbon counters
Operational Rating
Display Energy Certificate (DEC)
Actual use(Metered)
Roof, walls, windows, floors
Boilers, etcLow flow showers
Direct CO2
emissionsfrom
buildingenergy
demand
People Transformation
Zero carbon task force
For dwellings:Green mortgages
Council tax link to EPCStamp duty link to EPC
Asset Rating Energy
Performance Certificate (EPC)
Standard use(Calculated)
New buildings:Building
Regulations
Existing buildings:Fiscal incentives
Source: Robert Cohen, ESD
Headline indicator
Year-on-year improvement
Additional technical details in
fine print
Display Energy Certificates for buildings
CO2 emissions tonnes/year
DECARBONISING BUILDINGSCASE STUDY: The Sports Hall
The proposed sports halls is: - 36 x 40mx 7m high, - floor area of around 1440m2.- The currently preferred design includes:- 15 Sprung Sports Floor - Lighting should be Multi-Corso set between the badminton courts- Heating system is a Continuous Black Tube radiant heating system.- 160m2 sports storage equipment- Full height glazed screen between corridor and sports hall- Range of fixed equipment including basket ball goals, netball & badminton posts- Side walls to be green or blue to meet badminton requirements-Top 3m of the 3 external walls are designed to include Kalwall Transluscent- cladding, an insulating, diffuse, light transmitting system that eliminates glare hot spots and shadows.
Carbon Footprint Analysis as part of the design process of construction projects.
Michael Purkiss
Graduate Engineer
Dunedin House25 Ravelston Terrace
EdinburghEH4 3TP
The what works palette of RENs
Source: njsolar
Wind – It works and is available on site
House height 8m
400W turbineElectricity provision: 20% of a householdHeight: 2mCost: £1500-2000
6kW turbine
Electricity provision: 3.5 houses or 20% of a primary school
Height: 9m
Cost: £15-18k
220kW turbine
Electricity provision: 85 houses or 5 primary schools
Height: 36m
Cost: £550-700k
1.5MW turbine
Electricity provision: 1200 houses or 75 primary schools
Height: 65m
Cost: £1-1.5 million
CALCULATING THE COST BENEFITS OF THE SAVINGS:
Recommendation 3: Naturally ventilate the sports hall and eliminate the need for mechanical cooling and provision of fresh air. Removal of central ventilation plant and fans.
Electricity cost savings 34 kWh/m2/a saved by removal of mechanical ventilation system. = 1440 x 34 = 48960 kWh/a
CO2 savings 21.053 tonnes annumcost savings 1440 x 34 x 5.5 = £2693 annumCost of measure removes c. -£15,000 from plant cost and adds the same for
the opening Kalwal windows at the upper level. Payback 0 years
Recommendation 4: Under floor heating with GSHP power in part with a wind turbine
Replace all air blown sports hall heating system with under-floor heating from a ground source heat pump with wind turbine giving zero energy heating for the hall.
Heating gas saved 307 kWh/m2/a = 1440 x 307 = 442080 kWh/aCO2 savings 83.995 tonnes annumcost savings 442080 x 2.7 = £11,936 annumCost of measure £100,000Payback 8.38years
RENEWABLE ENERGY GRANTS:The Low Carbon Buildings Programme -
Stream 2B. (
www.lowcarbonbuildings.org.uk/ ).
• Solar photovoltaics 50%• Biomass 35%• Ground source heat pumps 35%• Wind turbines 30%• Solar thermal 30%
Recommendations:
• High the thermal efficiency of the structure of the sports hall through the use of good levels of insulation in north, south and east walls, elimination of air-infiltration through the building envelope and robust construction.
• Optimised use of natural lighting in the sports hall so reducing the need for high levels of artificial lighting.
• Naturally ventilated sports hall, eliminating the need for mechanical cooling and provision of fresh air.
• Replacement of the proposed high level, high temperature, gas fired, air blown heating system with an under-floor, low temperature heating system powered at least in part by a ground source heat pump system and a wind turbine situated in the school grounds.
• Install a roof mounted solar hot water system to provide part of the high temperature water supply needed for the changing room facilities.
The Aim Of The Project
To develop a Carbon Footprint calculation methodology suitable for
use in the design stage of construction projects.
Barriers to developing a methodology for the
construction industry • The lack of one globally agreed definition of the term ‘carbon footprint’.
• The lack of agreement on the units to be used in the calculation methodology - CO2 or CO2e?
• Analysis boundaries for construction projects – Cradle to Gate or Cradle to Grave? Must be clearly specified to avoid ‘double counting’ of emissions.
Barriers (continued). • The complexity of construction projects – How can a single emission figure be produced for the construction of 100m of 2 lane road carriageway? Calculation of the footprint of a project could involve data sharing and cooperation between the client, designers, contractors and subcontractors.
• The format and availability of data required for the methodology – in order to become an accepted part of the design process, data availability, collection and input can’t be a laborious time consuming process.
• Current legislation and policies – any methodology must comply with and contribute towards achieving targets and benchmarks set out in legislation.
What is the best strategy to reduce our dependence on Carbon intensive energy?
1. How do carbon emissions vary from different fuel types in reality?
2. How sensitive are these different types to carbon accounting?
Comparison study of Nuclear, Coal and Wind Energy with respect to Carbon Accounting
Samuel [email protected]
Carbon Accounting of Electricity Production.
• Material based analysis (gCO2/kg)– Life cycle analysis of products - Amount of materials must be known for a given project in
tonnes/kilograms– Requires inventories of all materials used in construction
• Mass of material x GHG embodiment per unit mass
– Widely used: “Inventory of Carbon & Energy” - Bath University. – Still no standard inventory.– Only valid for defined system boundary - process specific
• Cost based analysis (gCO2/£)– Life cycle analysis of processes - Inventory establishment for lifetime monetary cost of plant.
Emission factor found using GHG intensities - amount of GHG emitted from production of one unit worth
– Input-Output analysis– Assessment of how carbon intensive an economy is– Not case specific due to input-output tables & averaged intensities– Study suggests gives fuller account of emissions during construction1
• Combination of the two
1
Sensitivity of Electricity Production methods to carbon accounting
• Using published Life Cycle Assessments to deduce sensitivities of different production methods to quantifiable assessment.
Sensitivity = Contribution Score x Data Rating
Where
– Contribution score: The smaller the value, the lesser the contribution to total life cycle emissions
– Data Rating: • 1 - available, published data• 2 - generic data, assumptions and availability of choice present• 3 - missing data, omitted data
Source: Environment product Declaration of electricity from Torness Nuclear Power Plant by AEA Technology
Torness Life Cycle CO2 Emissions
The same technique was used for coal and wind energy:
Based on typical UK coal plant data
Based on Lewis Wind Farm project data & Danish data
Sensitivity vs.
Total Life Cycle Emissions
0
10
20
30
40
50
60
70
80
90
Coal Nuclear Wind
Sensitivity of Different Electricity production methods w.r.t. carbon accounting
989.7
255.3
5.0524.6
6.8
0
50
100
150
200
250
300
350
400
gC
O2
/kW
h
Coal Nuclear Wind
Total Life Cycle Emissions
Nuclear Power is currently the most vulnerable to carbon accounting
Sources:
1. AEA Technology - Environment product Declaration of electricity from Torness Nuclear Power Plant
2. Naser Odeh & Timothy Cockerill - LCA of typical coal power plant & LCA of coal plant with CCS
3. Lewis Wind Farm Proposal4. Elsam Engineering - LCA of onshore sited
wind farms
What does it all mean?
• Need to open debate of accountability of electricity production methods.• We need to have clear boundary definitions set that concern the entire life
cycle of projects - pressure on all energy related industries to account in a standard manner
• Reduce the number of assumptions made in assessments• Reduce involvement in projects with high degrees of uncertainty
• Need a structure in place to meet legislation• House of Commons suggests current average of 541gCO2/kWh
emissions factor to our electricity. This is the key figure to bring down, since it relates to every electricity-using object in Britain. Refers to our energy mix
• Need a structure in place to meet legislation• House of Commons suggests current average of 541gCO2/kWh
emissions factor to our electricity. This is the key figure to bring down, since it relates to every electricity-using object in Britain. Refers to our energy mix
Need to reach a point where we can assess all aspects of electricity production and, like the car’s MOT certificate, be able to say about a project: fix or scrap, based on quantifiable assessment.
Need to reach a point where we can assess all aspects of electricity production and, like the car’s MOT certificate, be able to say about a project: fix or scrap, based on quantifiable assessment.
I would like to invite you to open discussion on this topic.I would like to invite you to open discussion on this topic.
The current method of CO2 accounting is to calculate the CO2 emissions using the an emission factor for complete combustion of the fuel (CO2/J) and then apply the efficiency of combustion or electrical generation process
EF = EFf *
This allows, for instance nuclear generating capacity to be computed as zero carbon electricity i.e. EFf = 0
Notes from Andrew Peacock on the energy mix..
Source: Andrew Peacock
A central question that should therefore be asked is whether the total CO2 emissions associated with the delivery of the energy that provides the ultimate service (i.e. heat or electricity) should be assigned to its production
EF = (EFf * +EEf
This would therefore include mining of uranium in Australia and subsequent transportation and could also include storage of radioactive waste after use.
It could also include the mining of coal in Russia or South Africa and its subsequent transportation
Source: Andrew Peacock
Where the UK gets its Coal from – Imports ?
UK Imports more coal than it produces for the first time
Source: Andrew Peacock
Where the UK gets its Coal from
Source: Andrew Peacock
A further complication arises with assigning emission factors to electricity consumption. This can be summarised as:
The fuel mix used to generate electricity on the national grid varies with time.
This variation occurs for the existing network at a minutely, daily and seasonal level
In the future it is dependant on decarbonisation of the grid – what technologies and when
Source: Andrew Peacock
The way the grid operates to maintain supply and demand balance is that fossil fuel plants are kept in a state of readiness to allow them to come on stream to meet load perturbations.
This has an impact on CO2 emissions:
If the energy saving technology that is being investigated increases perturbations on the grid then this may therefore result in both an increase a reduction in network scale CO2 emissions. The saving in CO2 emissions is therefore net not gross
Unless the energy saving technology can be controlled in such a manner to prevent exacerbation of load perturbations
There is an absence of certainty
It is essential that carbon counting is done properly. A decision that one number is larger than another may set off a whole train of policy action.
Just as the ‘financial engineering’ of a wind farm project may be as important as the nuts and bolts, so it will be with serious carbon counting.
The importance of getting the right numbers and accounting procedures
Bob Everett: Open University
The problem seems to be to get the numbers to lie down on the paper
and stop wriggling.
What we need is a Carbon Accounting Network
for Buildings and Cities
“What we need is an Institute of Carbon Accounting
to sort these Issues out and validate methodologies”
Colin Challen MPChair, All Party Parliamentary Climate Change Group
Holyrood Carbon Accounting Conference29th April 2008.