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 ChapmanSc117@hw.ac.uk

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.