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Whole life carbon accounting for the Treasury Green Book John Connaughton Davis Langdon

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.

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Whole life carbon accounting for the Treasury Green Book John Connaughton Davis Langdon

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  1. Whole life carbon accounting for the Treasury Green Book John ConnaughtonDavis Langdon Global construction consultants

  2. 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 Carbon Accounting: Key points

  3. Whole life 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) Whole life Carbon Footprint Embodied CO2 In-use CO2

  4. 75% 0% 100% 50% 25% BASIC STRUCTURES OFFICES EMBODIED IMPACTS HOUSING SPORTS BUILDINGS, STADIA INFRASTRUCTURE 0% 25% 50% 75% 100% OPERATIONAL IMPACTS HIGHLY SERVICED BUILDINGS 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?

  5. Towards Zero CO2 Operational Impacts BASIC STRUCTURES 75% 0% 100% 50% 25% EMBODIED IMPACTS OFFICES HOUSING SPORTS BUILDINGS, STADIA OPERATIONAL IMPACTS INFRASTRUCTURE 0% 25% 50% 75% 100% HIGHLY SERVICED BUILDINGS Why embodied? What is the impact of the trend towards ‘zero carbon’ buildings?

  6. Holorib Lightweight Concrete Shear Studs Mass /m2 Mass /m3 Mass /m2 Mass/nr Carbon/kg Carbon/kg Carbon/kg Carbon/kg Carbon /m2 Composite Upper Floor Mesh Reinforcement Calculating Embodied Carbon

  7. Cement Mass /m2 Mass /m2 Mass /m2 Carbon /m2 Sand and Aggregate Calculating Embodied Carbon GBBS OPC PFA Carbon/kg Lightweight Concrete Carbon/kg Carbon/kg Water

  8. 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?

  9. Embodied CO2 benchmarking with Davis Langdon’s Carbon Calculator Sample of 48 office projects assessed by Davis Langdon Embodied KgCO2 per m2 GIA 250-500 0-250 500-600 600-700 700-800 800-900 1500-2000 1500-2000 2000-2500 900-1000 1000-1250 2500-3000 1250-1500

  10. Offices CO2 emissions study Embodied CO2 of 10 different office projects from the same developer Embodied kgCO2 per m2 GIA

  11. Whole life carbon impact : the bigger picture Recent study by a major offices developer to assess CO2 in existing office stock Embodied in construction materials and components Construction Emitted from the use of energy by the building occupants and processes Operational Emitted in travelling to and from the building Commuting Total impact

  12. The increasing significance of embodied carbon Whole life CO2 emissions annualized for 30 years with adjustments London W Past Present Near Future 11% 11% 15% 20% 71% 71% 62% 52% 23% 28% 17% 17%

  13. 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

  14. Whole life carbon methodologyA life cycle assessment approach CEN/TC 350 Product ‘information module’ Building life cycle Recycling for other ‘systems’

  15. Recyclability Recycled content Whole life carbon methodologyA life cycle assessment approach CEN/TC 350

  16. 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?

  17. 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 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

  18. Whole life carbon accounting for the Treasury Green Book John Connaughton john.connaughton@davislangdon.comDavis Langdon Global construction consultants

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