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Zero Carbon: Implications and Issues

Zero Carbon: Implications and Issues. Malcolm Bell Buildings, Energy and Sustainability Group, School of the Built Environment, Leeds Metropolitan University, Leeds, UK. Paper presented to: Towards Zero Carbon Homes 5 July 2007, Milton Keynes, UK. Towards Zero Carbon. Towards Zero Carbon.

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Zero Carbon: Implications and Issues

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  1. Zero Carbon: Implications and Issues Malcolm Bell Buildings, Energy and Sustainability Group, School of the Built Environment, Leeds Metropolitan University, Leeds, UK. Paper presented to: Towards Zero Carbon Homes 5 July 2007, Milton Keynes, UK.

  2. Towards Zero Carbon

  3. Towards Zero Carbon

  4. Compliance packages:Zero Carbon 80m2 Semidetached or end terraced 2 storey house

  5. Base Case - TER

  6. Zero Carbon (TER of -135% to -150%)

  7. Zero Carbon (TER of -135% to -150%)

  8. Source: Wall (2006), Photo: Hans Eek Airtightness 1 m/h Passive House Standards Timber frame scheme Göteborg, Sweden (120 m2) MVHR – 80% with duct heaters 5m2 Solar water + resistance top-up

  9. 5,868 kWh 6,420 kWh Total energy = 8,160 kWh/a Passive House Standards Timber frame scheme Göteborg, Sweden, 120 m2 Source: Wall (2006), Photo: Hans Eek TER (kgCO2/m2) Design ≈ 10.6 Actual ≈ 15.3 Under Swedish conditions! Source: Wall (2006), Energy and Buildings. 38, pp 627-634

  10. Implications and issues • Lights and appliances represent between 60% and 70% of carbon emissions. • Over 5,000 kWh/a may need to be generated by zero carbon sources. (more for larger houses) • What chance at the level of the dwelling?

  11. Solar thermal?

  12. Solar thermal?

  13. Micro wind?

  14. Micro wind?

  15. Micro wind? Manufacturer’s general claims: 1.5 kW (max at 12.5 m/s) Annual energy generated - 2,000 - 3,000 kWhs – depending on position and location. Carbon displacement – 1.3 tonnes (30% utilisation) Location: Average wind speed (DTI database) = 5.1 m/s @ 10m Energy – 1,473 kWhs But what about shelter from trees and other buildings?

  16. Micro wind? 5.1 m/s 4 m/s 3 m/s

  17. Photovoltaic panels

  18. Cost and scale

  19. Cost and scale • Wind • small scale – 17 p/kWh • large scale – 4 p/kWh • PV • Small scale – 55 p/kWh • large scale – 23 p/kWh • Solar thermal • small scale – 9 p/kWh • large scale – 7 p/kWh preliminary calculations – Barrett 2007

  20. Biomass? Biomass in a 2006 dwelling!

  21. Biomass? Biomass in a 2016 dwelling

  22. So what, so far ? • Site based generation is problematic. • Solar thermal - useful demand reduction • Wind is likely to be cheaper and more effective at large scale • Biomass may have limited value in CHP but no panacea and an important strategic resource • Need to link new building to strategic renewable provision.

  23. Source: Wall (2006), Photo: Hans Eek So what for the industry? Focus attention on as low an energy/carbon demand as possible Deal with generation in a strategic way

  24. But! Does new housing do what it says on the tin?

  25. +75% +104% Notional – v – Real heat loss The question is: Why?

  26. Thermal bridges

  27. Thermal bridging & construction Designed performance is almost always degraded

  28. Timber fraction and insulation

  29. Airtightness is improving?

  30. Sequencing and process

  31. Hidden leakage

  32. A culture of detailed planning?

  33. A culture of detailed planning? Build – Destroy – Install – Repair

  34. Party wall heat bypass Understanding complex heat loss paths

  35. Potential CO2 savings Fabric heat loss is between 40% and 50% greater than currently estimated. Eliminating the bypass would produce large actual CO2 savings Assumes Party Wall U Value = 0.5 Assumes 10% semi, 20% terrace in stock and new build Calculations for semis and terraces only – no estimate for apartments

  36. We have been rumbled! As very low and zero carbon becomes mandatory small things will matter This time customers will notice! This time building control will notice! We cannot hide behind flawed assumptions

  37. The industry must change! • It has been said before • But the more it changes the more it remains the same • Old problems persist! • It is time to retool, to retool cultures and processes as well as technology.

  38. What will change look like? • A fully managed process – inception, design, construction and support in use. • Performance will have to be guaranteed. • A quality control process based on measurement not assumption • Re-engineering of processes as well as technology will bring economies! • Constant feedback will bring constant improvement.

  39. So what does zero carbon mean?

  40. The world will not be the same! Thomas Kuhn The Structure of Scientific Revolutions We are entering a new paradigm

  41. So what does zero carbon mean? As in science, so in construction: It is time for the industry to Retool!

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