Transcript Whole life carbon accounting for the Treasury Green Book

Whole life carbon accounting for the Treasury Green Book
John Connaughton
Davis Langdon
Global
Global construction
construction consultants
consultants
Whole life Carbon Accounting: Key points
The concept of whole life carbon
The importance of ‘embodied’ carbon
What whole life carbon assessment looks like
Green Book and carbon accounting issues
Key challenges and emerging thinking
Whole life CO2
Whole life Carbon Footprint
Embodied CO2
In-use CO2
Regulation (Part L) is reducing the relative significance of in-use emissions
Major construction materials/components are relatively energy intensive,
and
Many low energy/carbon strategies are resource intensive (eg increased
mass; tehcnology strategies)
Why embodied?
Rule of thumb: 75:25 operational to embodied ratio for buildings
BUT IS THIS CORRECT?
Surely the proportion will vary depending on building type?
BASIC STRUCTURES
75%
50%
100%
0%
25%
EMBODIED
IMPACTS
OFFICES
SPORTS BUILDINGS, STADIA
0%
INFRASTRUCTURE
25%
HOUSING
OPERATIONAL
IMPACTS
50%
75%
HIGHLY SERVICED BUILDINGS
100%
Why embodied?
What is the impact of the trend towards ‘zero carbon’ buildings?
100%
BASIC STRUCTURES
75%
Towards Zero CO2 Operational Impacts
50%
0%
25%
EMBODIED
IMPACTS
OFFICES
HOUSING
SPORTS BUILDINGS, STADIA
OPERATIONAL
IMPACTS
INFRASTRUCTURE
0%
25%
50%
75%
HIGHLY SERVICED BUILDINGS
100%
Calculating Embodied Carbon
Composite
Upper
Floor
Holorib
Mass
/m2
Carbon/
kg
Lightweight
Concrete
Mass
/m3
Carbon/
kg
Mesh
Reinforcement
Mass
/m2
Carbon/
kg
Shear Studs
Mass
/nr
Carbon/
kg
Carbon
/m2
Calculating Embodied Carbon
GBBS
OPC
PFA
Cement
Mass
/m2
Carbon/
kg
Sand and
Mass
/m2
Carbon/
kg
Mass
/m2
Carbon/
kg
Lightweight
Concrete
Aggregate
Water
Carbon
/m2
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
Sample of 48 office projects assessed by Davis Langdon
0
1
0
1
1
3
4
4
4
6
7
7
10
Embodied KgCO2 per m2 GIA
Offices CO2 emissions study
Embodied CO2 of 10 different office projects from the same developer
Embodied kgCO2 per m2 GIA
19
161
106
60
150
92
70
162
197
140
218
46
77
60
258
191
181
146
123
85
359
366
392
125
120
191
215
220
147
138
142
811
189
423
357
455
354
385
229
Structural elements
Building fabric
77
Internal walls and finishes
M&E
Whole life carbon impact : the bigger picture
Recent study by a major offices developer to assess CO2 in
existing office stock
Construction
Operational
Commuting
Total impact
Embodied in construction
materials and components
Emitted from the use of energy
by the building occupants and
processes
Emitted in travelling to and from
the building
The increasing significance of embodied carbon
Whole life CO2 emissions annualized for 30 years with adjustments
London W
Past
Present
Near Future
11%
15%
20%
71%
62%
52%
23%
17%
Commute
Operational
28%
Embodied
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
impacts
Assesses costs and benefits at market rates
Some important issues for whole life
carbon:
Green Book excludes sunk costs
Includes residual value (at end of life?)
Assessign GHG emissions – reference to
DEFRA work on social cost of carbon
Whole life carbon methodology
A life cycle assessment approach
CEN/TC 350
Product ‘information module’
Building life cycle
Recycling for other ‘systems’
Whole life carbon methodology
A life cycle assessment approach
CEN/TC 350
Recycled
content
Recyclability
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 stages
Product
Construction
In use
End of life
Embodied
Including ‘start of life’ demolition, enabling work
Including repair, maintenance and replacement
Including ‘end of life’ demolition; recyclability?
This could help:
Set and understand benchmarks
Improve the regulatory focus
Whole life carbon accounting for the Treasury Green Book
John Connaughton
Davis Langdon
[email protected]
Global
Global construction
construction consultants
consultants