Carbon Accounting Buildings | Sue Roaf Presentation Transcript
Questions concerning the Carbon Accounting of Buildings Heriot Watt Carbon Accounting Conference 11 th 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 CO 2 100 0 200 300 Source: Robert Cohen
Cost of household energy in different worlds Extreme refurbishment: demand cut by two thirds Demand stays same Gas Electricity 2.7 13 2.9 4.6 22 14 18 66 Source: Robert Cohen
Source: Robert Cohen
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 DIRECT EMISSIONS 34% HOUSE ENERGY 19.5% TRANSPORT ENERGY 14.5% INDIRECT PRO RATA EMISSONS 51% INDIRECT INFRASTRUCTURAL EMISSONS 15%
“ 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:
What is a Carbon Footprint? Source: Robert Cohen
CO 2 or CO 2 equivalent
Six gases are controlled under the Kyoto protocol. CO 2 e expresses greenhouse gas emissions as the amount of CO 2 with the same global warming potential
How to Calculate a Carbon Footprint 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 Weaknesses
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
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
The roots of building energy consumption Asset Control & management Asset Control & management Source: Bill Bordass Total energy use per m 2 (primary or CO 2 equivalent) Lighting kWh/m 2 Efficiency (W/m 2 )/100lx Hours of use Effective hours/yr Management factor Vent rate (l/s)/ m 2 Ventilation kWh/m 2 Ventilation W/m 2 Efficiency W/(l/s) Effective hours/yr Management factor Hours of use Other uses A B B D F G H C D E F G H Light level Lux E Lighting W/m 2 C
Policy map: using EPCs and DECs to count direct carbon emissions from buildings Source: Robert Cohen, ESD
Display Energy Certificates for buildings Headline indicator Year-on-year improvement Additional technical details in fine print CO 2 emissions tonnes/year
CASE 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 House 25 Ravelston Terrace Edinburgh EH4 3TP
The what works palette of RENs Source: njsolar
Wind – It works and is available on site House height 8m 400W turbine Electricity provision: 20% of a household Height: 2m Cost: £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 annum
cost savings 1440 x 34 x 5.5 = £2693 annum
Cost 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/a
CO2 savings 83.995 tonnes annum
cost savings 442080 x 2.7 = £11,936 annum
Cost of measure £100,000
RENEWABLE ENERGY GRANTS: The Low Carbon Buildings Programme - Stream 2B. ( www.lowcarbonbuildings.org.uk/ ).
Solar photovoltaics 50%
Ground source heat pumps 35%
Wind turbines 30%
Solar thermal 30%
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 - CO 2 or CO 2e ?
Analysis boundaries for construction projects – Cradle to Gate or Cradle to Grave? Must be clearly specified to avoid ‘double counting’ of emissions.
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?
How do carbon emissions vary from different fuel types in reality?
How sensitive are these different types to carbon accounting?
Comparison study of Nuclear, Coal and Wind Energy with respect to Carbon Accounting Samuel Chapman [email_address]
Carbon Accounting of Electricity Production .
Material based analysis (gCO 2 /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 (gCO 2 /£)
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
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 construction 1
Combination of the two
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
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 CO 2 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 Nuclear Power is currently the most vulnerable to carbon accounting
AEA Technology - Environment product Declaration of electricity from Torness Nuclear Power Plant
Naser Odeh & Timothy Cockerill - LCA of typical coal power plant & LCA of coal plant with CCS
Lewis Wind Farm Proposal
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 541gCO 2 /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. I would like to invite you to open discussion on this topic.
The current method of CO 2 accounting is to calculate the CO 2 emissions using the an emission factor for complete combustion of the fuel (CO 2 /J) and then apply the efficiency of combustion or electrical generation process EF = EF f * This allows, for instance nuclear generating capacity to be computed as zero carbon electricity i.e. EF f = 0 Notes from Andrew Peacock on the energy mix.. Source: Andrew Peacock
A central question that should therefore be asked is whether the total CO 2 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 = (EF f * +EE f 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 ? 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 CO 2 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 CO 2 emissions. The saving in CO 2 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 MP Chair, All Party Parliamentary Climate Change Group Holyrood Carbon Accounting Conference 29 th April 2008.