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Whole life carbon accounting for the Treasury Green Book John Connaughton Davis Langdon. Global construction consultants. The concept of whole life carbon. The importance of ‘embodied’ carbon. What whole life carbon assessment looks like. Key challenges and emerging thinking. - PowerPoint PPT Presentation
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Global construction consultants Global construction consultants
Whole life carbon accounting for the Treasury Green Book
John ConnaughtonDavis Langdon
Whole life Carbon Accounting: Key points
The concept of whole life carbon
The importance of ‘embodied’ carbon
What whole life carbon assessment looks like
Key challenges and emerging thinking
Green Book and carbon accounting issues
Whole life CO2
Whole life Carbon Footprint
In-use CO2Embodied CO2
Regulation (Part L) is reducing the relative significance of in-use emissionsMajor construction materials/components are relatively energy intensive, andMany low energy/carbon strategies are resource intensive (eg increased mass; tehcnology strategies)
Why embodied?
Rule of thumb: 75:25 operational to embodied ratio for buildingsBUT IS THIS CORRECT? Surely the proportion will vary depending on building type?
100% 75% 50% 25% 0%
100%75%50%25%0%
OPERATIONAL IMPACTS
EMBODIED IMPACTS
INFRASTRUCTURE
HIGHLY SERVICED BUILDINGS
HOUSING
OFFICES
SPORTS BUILDINGS, STADIA
BASIC STRUCTURES
Why embodied?
What is the impact of the trend towards ‘zero carbon’ buildings?
OPERATIONAL IMPACTS
EMBODIED IMPACTS
INFRASTRUCTURE
HIGHLY SERVICED BUILDINGS
HOUSING
OFFICES
BASIC STRUCTURES100% 75% 50% 25% 0%
100%75%50%25%0%
SPORTS BUILDINGS, STADIA
Towards Zero CO2 Operational Impacts
Calculating Embodied Carbon
Holorib
Lightweight Concrete
Mesh Reinforcement
Shear Studs
Mass /m2
Mass /m3
Mass /m2
Mass/nr
Carbon/kg
Carbon/kg
Carbon/kg
Carbon/kg
Composite Upper Floor
Carbon /m2
Calculating Embodied Carbon
Sand and
AggregateCarbon/
kg
Cement Mass /m2
Mass /m2
Carbon/kg
Lightweight
ConcreteCarbon /
m2
OPC
GBBS
PFA
WaterMass /m2
Carbon/kg
Some challenges
Basic construction materials
How much carbon is used in the production of, say, 1 tonne of cement?
Composites
How much cement (kgs) is there in 1 m3 of 1.5:2:3 concrete mix?
Construction metrics
How much by mass (kg) of 1.5:2:3 concrete is there in 1 m2 composite floor slab?
Embodied CO2 benchmarking with Davis Langdon’s Carbon Calculator
1
4 4
1
0
1
0
3
4
7
6
7
10
Sample of 48 office projects assessed by Davis Langdon
Embodied KgCO2 per m2 GIA
0-25
0
250-
500
500-
600
600-
700
700-
800
800-
900
900-
1000
1000
-125
0
1250
-150
0
1500
-200
0
1500
-200
0
2000
-250
0
2500
-300
0
Offices CO2 emissions study
423357
229359 366 392
455354 385
81160 191
189
146 123 85
147
138142
77
77
218
258162 197 181
191
215220
161
46
106150
92 70 140
60125
120
19
Structural elements Building fabric Internal walls and finishes M&E
Embodied CO2 of 10 different office projects from the same developer
Embodied kgCO2 per m2 GIA
Whole life carbon impact : the bigger picture
Construction
Commuting
Operational
Total impact
Embodied in construction materials and components
Emitted in travelling to and from the building
Emitted from the use of energy by the building occupants and processes
Recent study by a major offices developer to assess CO2 in existing office stock
Commute Operational Embodied
The increasing significance of embodied carbon
Whole life CO2 emissions annualized for 30 years with adjustments
London W
Present Near FuturePast
11%
71%
17%
11%
71%
17%
15%
62%
23%
20%
52%
28%
The Green Book
Best practice techniques for project and policy assessment
Describes how economic, financial, social and environmental assessments should be combined
Where possible, attributes monetary values to impactsAssesses costs and benefits at market rates
Some important issues for whole life carbon:
Green Book excludes sunk costsIncludes residual value (at end of life?)Assessign GHG emissions – reference to DEFRA work on social cost of carbon
CEN/TC 350
Whole life carbon methodologyA life cycle assessment approach
Product ‘information module’
Building life cycle
Recycling for other ‘systems’
CEN/TC 350
Whole life carbon methodologyA life cycle assessment approach
RecyclabilityRecycled content
Current measurement issues and challenges
Will CEN/TC 350 resolve them?
Consistent product data – what are things actually made of?
Consistent carbon data – what is the impact?Manufacturing processes, energy sources, location/transport, etc
Bio-renewable (organic) materials
Boundary conditions – including accounting for recycled content and recyclability?
Some thoughts on whole life carbon accounting
Shortcomings in ‘global’ indicators for buildings – eg kgs of whole life CO2 per square metre floor area
Take a lead from CEN/TC 350 and express impacts over key stagesProduct Embodied
Construction Including ‘start of life’ demolition, enabling work
In use Including repair, maintenance and replacement
End of life Including ‘end of life’ demolition; recyclability?
This could help:Set and understand benchmarks
Improve the regulatory focus
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