Quantification of carbon emissions from the UK building stockPaul DavidsonDirector, Sustainable EnergyNovember 2009

Overview

• Contribution of buildings to UK carbon emissions

• Modelling energy use in the UK buildings

• Technical and cost effective potential for carbon savings

• Scenario modelling

• Low and zero carbon new build

• Emission factors for delivered energy

Where the emissions come from

Carbon Dioxide Emissions from UK Delivered Energy Use 2007

transport30%

agriculture1%

housing28%

commercial13%

industrial building

3%

industrial process

22%

public sector3%

BRE, 2009

Quantification for individual buildings

• Energy Performance Certificates now in place for all buildings

• Calculated based on standardised methodologies

Modelling energy flows

Fuel supply Walls

Solar gain

Flue lossesBoiler

Cooker

Total spaceheating load

Heat losses:

Windows

Ventilation

Appliances

Other gains

Floor lossWaste water

Roof loss

BREDEM - BRE Domestic Energy Model

SAP – The Government’s Standard Assessment Procedure

for energy rating of dwellings

Calculation is carried out by a computer program based on SAP specification

For existing buildings, RdSAP (Reduced Data) does the calculation with limited information

SAP - the UK methodology for calculating energy performance of dwellings

cSAP – implements proposed SAP2009

SBEM – for non-domestic buildings• Current version v3.4.a released May 2009

• Provides Building Regs compliance and EPCs in England, Wales, Scotland, N Ireland, Republic of Ireland and Jersey

End-use breakdown

• Total consumption330 kWh/m2/yr

• Cooling and lighting dominate

• But other systems could be improved

Building stock energy models

• Housing – BREHOMES– First developed in 1970s– Data on housing stock by type, tenure, age, size, location, etc– Uses BREDEM to do energy calculations– Uses various existing data sources, with the aim of making the best of

what is available– Principal source is market research surveys that started in the 1970s and

has been carried out every year since– Excellent long-term trend information on insulation and heating systems

Building stock energy models

• Non-Domestic – N-DEEM– Developed from 1990s– Basic data on rateable premises (England and Wales) - detailed

characteristics on 1.3 million of these.– Energy Audits on range of premises (700 plus) – Other Data sources as and when available– Dynamic simulation model used to assess savings

How we use the models

• Technical support for UK climate change policy– 15+ years

• Developing Scenarios– Future changes in energy use and carbon emissions – Business as usual– With additional policy options– With new and emerging technologies

• Cost abatement analysis– Cost effectiveness of applying specific energy efficiency measures across

the building stock– Feeds into cost benefit analysis for policy options

BREHOMES - Loft insulation trend

Ownership of loft insulation

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006

Year

Perc

enta

ge o

f pot

entia

l

Not stated<1"1"2"3"4" or more

Delivered Energy Use broken down by End use for Non-domestic Buildings - 2007

Annual Delivered Energy Consumption from Non-Domestic Buildings

0 10000 20000 30000 40000 50000 60000

industrial buildings

commercial office

communication and transport

further and higher education

government estate

health

hospitality

leisure

other government

other service sector

retail

schools

warehousesB

uild

ing

type

GWh pa

catering computing cooling hot w ater lighting other space heating

Developing scenarios for future energy use and carbon emissions

Market penetration of home energy efficiency measures

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050

Year

Perc

enta

ge o

f pot

entia

l

Condensing boilers

Cavity wall insulation

Hot water tank insulation

Central heating

Double glazingDraught proofing

Loftinsulation(any)

Scenarios for UK Service Sector Emissions

-

5

10

15

20

25

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Year

Ann

ual e

mis

sion

s (M

tC)

referencepolicyextended policystep change 1step change 260% below 1990

Zero Carbon New Build

• Is it feasible?

• Are there building types where it might be difficult to achieve zero carbon?

• How much will it cost

Feasibility of zero carbon new build for non-domestic buildings

CO2 Emissions from new build to 2006 regs

-

100

200

300

400

500

600

Heating Cooling Auxiliary Lighting DHW Equip

End use

Tonn

es C

O2

pa

Industrial

Other Services

Warehouses

Sport and Leisure

Retail

Hotel

Health

Government

Education

Communicationsand TransportCommercial Offices CO2 Emissions from new build to max building regulations plus solar

thermal hot water and biomass boilers and PV

0

100

200

300

400

500

600

Heating Cooling Auxiliary Lighting DHW Equip

End use

Tonn

es C

O2

pa

IndustrialOther ServicesWarehousesSport and LeisureRetailHotelHealthGovernmentEducationCommunications and TransportCommercial Offices

Preliminary assessment based on few example buildings

Zero carbon new buildings v existing stock

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Year

Num

ber o

f dw

ellin

gs (0

00)

Post 2005 StockPre 2005 stock

30%

70%

Source: Housing Statistics – ODPM 2004

Cost effectiveness of carbon dioxide emission savings in existing dwellings

Cost effectiveness of carbon dioxide emission savings in the existing stock

-300

-200

-100

0

100

200

300

400

500

600

700

0 20 40 60 80 100 120 140 160

Carbon saving potential (MtCO2/yr)

Net

ann

ual c

ost o

f car

bon

save

d (£

/tCO

2)

A-rated condensing boiler

Solid wall insulation

Pre-1976 cavity wall insulation

1976-83 cavity wall insulation

Post 1983 cavity wall insulation

Solar water heating

Mini wind turbines

Photovoltaic panels

Micro wind turbines

A-rated cold appliances

A-rated wet appliances

Double glazing

Insulated doors

From ‘Do zero carbon homes make sense?’ Shorrock & Henderson, BRE. Proc. ECEEE Summer Study, June 2009. Also to be published in a BRE Trust report.

Cost effectiveness of emission savings in the existing stock – plus Code level 6 for all new homes

Cost effectiveness of carbon dioxide emission savings in the existing stock(Code level 6 carbon dioxide emission savings in new homes also shown)

-300

-200

-100

0

100

200

300

400

500

600

700

0 20 40 60 80 100 120 140 160

Carbon saving potential (MtCO2/yr)

Net

ann

ual c

ost o

f car

bon

save

d (£

/tCO

2)

Code for Sustainable Homes level 6

Carbon savings from each Level of the Code for Sustainable Homes compared to those possible from

improving existing homes

• Note: only cost-effective savings from improving existing homes are shown here – additional savings would be possible if non cost-effective measures were included

Carbon dioxide emission reductions in 2050 relative to 1990 compared with the 80% target

Carbon dioxide emission reductions in 2050 relative to 1990

(assuming that all cost-effective measures in existing homes are undertaken and that new homes are built to 2006 Regulations or one of the six levels of the Code for Sustainable Homes)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2006 Regulations Level 1 Level 2 Level 3 Level 4 Level 5 Level 6

Level of the Code for Sustainable Homes to which new homes are built

Perc

enta

ge o

f 199

0 em

issi

ons

(154

.4 M

tCO

2)

80% target(123.5 MtCO2 saved)

25 MtCO2 shortfall in savings which will have to be made up by de-carbonising the supply of electricity and heat

76.6 MtCO2

saved

77.7 MtCO2

saved

78.6 MtCO2

saved

81.2 MtCO2

saved88.8 MtCO2

saved98.4 MtCO2

saved

75.2 MtCO2

saved

Cost effectiveness of carbon dioxide emission savings in the non-domestic stock (with savings for Levels 1 – 4 for new non-domestic

buildings also shown) – Provisional Results

Forthcoming publication from BRE Trust late 2009:

Zero carbon new build and energy efficient refurbishment of existing building stock

Also – similar report for non-domestic

Both can be downloaded from BRE website: www.bre.co.uk/energy

SAP Emission Factors

• Previously– CO2 only– Covers important upstream emission sources

• Proposed from 2010– All significant GHG– More comprehensive coverage of upstream emissions– Consistent treatment of all fuels

• Issues– Consistency with other factors - Act on CO2,, Company reporting

guidelines, Factors used for policy assessment, Road Transport Fuel Obligation for biofuels

– future change in generation mix for electricity is uncertain

Summary

• Buildings account for 46% of UK carbon emissions – more if embodied carbon emissions are taken into account

• Modelling energy use in the UK building stock:– Identify technical and cost effective potential for carbon savings – CE potential of the existing

stock is significant– Scenario modelling – indicates that achieving 80% reduction by 2050 requires uptake of existing

cost effective potential, plus significant uptake of low carbon technologies

• Zero carbon new build– More expensive than tackling existing building stock (probably not achievable for all non-

domestic buildings) and won’t save enough carbon. – Even when upgrading the existing stock and zero carbon new build combined, not sufficient to

achieve an 80% reduction in emissions by 2050

• Emission factors for delivered energy– Important that factors reflect real impact – but direction of future change for electricity is

uncertain