ENV-2D02 Energy Conservation 2006

1. ENV-2D02 Energy Conservation 2006 Energy Analysis & Lifecycle Assessment

2. Energy Analysis • A method for calculating the total amount of primary energy required to provide a good or service • Also called: energy budgeting, accounting & costing • Heyday - 1970s • Ian Boustead (1972) energy used in beverage containers • 1979 Handbook of Industrial Energy analysis • Developed into • Life cycle assessment • Life cycle energy analysis • Embodied energy • Life cycle energy analysis (LCEA) • an approach in which all energy inputs to a product are accounted for, not only direct energy inputs during manufacture, but also all energy inputs needed to produce components, materials and services needed for the manufacturing process. Early expression used for the approach is energy analysis. • Can include an LCA of energy production • eg electricity generation, biofuels • Or an LCA that is limited to energy criteria

3. Not to be confused with life cycle costing (LCC) • A technique to quantify the financial costs of a product throughout it’s lifetime • Does not usually include environmental criteria • external costs - costs to society • Capital cost + operating cost + maintenance + recycling + disposal • Can be combined with energy analysis/LCA

4. Lifecycle energy analysis manufacture extraction processing transport reuse/ recycling energy waste heat use end of life final disposal

5. Lifecycle assessment manufacture extraction transport waste heat processing energy reuse/ recycling waste materials use emissions water end of life final disposal Functional unit

6. Functional unit • Relates to the function a product or service will deliver • Energy analysis • A unit of delivered energy (kWh) • Energy to heat a home for a year • Energy to build a nuclear power station or a wind turbine or a house • embodied energy • Lifecycle assessment • Washing machine – 5 kg clothes • Packaging for 1 litre milk • Disposal of Norfolk’s waste

7. Lifecycle assessment stages Four major stages • Goal and scope definition • defines the purpose • extent of the study – boundaries • description • functional unit • Life cycle inventory • detailed compilation of all environmental inputs and outputs for each stage of the life cycle • results in a long list of resources and emissions, usually in incompatible units • Life cycle impact assessment • quantifies and aggregates the relative importance of all environmental burdens obtained in the LCI • Interpretation of the results

8. Problems with LCA & LCEA • Some impacts can’t be measure • Site specific vs average analysis • Results of lifecycle inventory (LCA) • long lists of environmental impacts all in different units • decision making process • Assumptions: results can be different for similar studies • Boundary issues • Allocation problems • Just a snapshot of the environmental impacts • does not easily take long term effects into consideration • Split between the scientists and engineers who are trying to develop a scientifically-defensible tool and the business managers and policy makers who are trying to make sound environmental decisions

9. LCA of Construction and Demolition Waste (EPSRC)

10. Lifecycle impact assessment • Two mandatory elements • classification • assigns the inventory results to different impact categories such as global warming • characterisation • calculates a category indicator result for each impact category using characterisation factors such as carbon dioxide equivalents • Two optional elements • normalisation • Benchmarks the aggregated emissions against a known total effect, e.g. average annual European emission the total national emissions • Normalization enables you to see the relative contribution from the material production to each already existing effect. • weighting • A range of methods used to explore the relative importance of the aggregated emissions

11. Weighting the relative importance of criteria • Distance to target • Panel method • Experts • Decision makers • Environmental groups • General public • Economic valuation • A set of valuation factors that is widely acceptable has not yet been established Euros per tonne carbon

12. Boundary problems

13. embodied energy manufacture extraction ‘Cradle to gate’ processing reuse/ recycling energy waste heat use end of life LCA/ LCEA ‘Cradle to grave’ final disposal

14. Geographic boundaries

15. More boundary problems: depth of study • First order • Direct inputs into product manufacture • Energy that made the bricks for a house • Second order • Inputs into manufacture of machines that manufacture the product • Energy used to made the machine that manufactured the bricks • Third order • Energy that made the machines, that made the machines that manufactured the bricks!

16. and more boundary problems ……. extent of analysis • Energy only • Simple LCA • eg carbon emissions • Full LCA • Time consuming & expensive • Data availability

17. Embodied energy the energy needed to convert raw materials in the ground into a final product

18. Embodied energy • Does not refer to the energy available or inherent in a material or product • E.g. the energy recovered by burning a product • Could be called “Cumulative Energy Demand” - the sum of all the energy inputs into a product system • ‘Embedded energy’ also used but not really correct • Embedded generation is electricity generation (eg CHP) which is connected to a distribution network rather than to the high voltage National Grid. • In general the more manufacturing processes a product goes through, the higher its embodied energy will be • E.g. timber board materials have a much higher embodied energy than the equivalent size of rough sawn timber. • The energy embodied in new construction and renovation each year accounts for about 10% of UK energy consumption. • 50% winning and manufacture of the materials • 50% used in transport

19. Elements of embodied energy • Electricity (delivered) • Energy losses in electricity production • fuel conversion at power plant (typically 60-70% of primary fuel input) • transmission and distribution losses (typically 2-8%) • Fuel extraction, processing and delivery • Energy consumption delivering fuel for use in power plants, transport equipment and industrial plant (typically 2-10%) • Process heat • Transport • Feedstock • fuel used in situation where they are not directly oxidized such as oil and gas in plastics, carbon in cokes and pitch and so on. • Energy in capital equipment

20. Embodied energy of building materials

21. Energy consumption for a typical house & low energy house(Crane Environmental Ltd, 2000) Low energy house Typical house

22. Combines LCEA and LCC:Financial & energy payback for a solar water pre-heater (Crane Environmental Ltd, 2000)

23. Example of simple LCALife cycle carbon dioxide emission figures for various generation technologies(Vattenfall, 1999)

24. More complex analysis:LCA & lifecycle cost models for building construction developed by Hong Kong Govt.

25. Example of energy analysis of recycling broken glass

26. Energy requirement for melting raw material with differing amounts of recycling

27. Energy requirements for raw production for 1 unit of new material

28. Energy and economic evaluation of building-integrated photovoltaics (Oliver & Jackson, 1999) • Energy viability • 1970s – suggestion that photovoltaics were not viable in energy terms • More recent studies – energy payback terms fraction of lifetime & likely to fall • This study compares: • European electricity mix • centralised PV • building integrated PV (PiPV)

29. Energy and economic evaluation of building-integrated photovoltaics (Oliver & Jackson, 1999) • Methodology • Functional unit 1 kWh delivered electricity • Compare costs in energy & economic terms • Energy analysis & lifecycle costs (p/kWh) • Average EU mix, Central PV, BiPV, Building integrated PVs (Zicer) has two functions • Generates electricity – displaces conventional energy system • Weatherproofing function – displaces conventional cladding system • Net BiPV

30. Assumptions • BiPV systems • Output 850 kWh/kWp/year • Electricity produced is consumed within building • Building has high base load demand • Hospital, university • No export to the grid • BIPV cladding substitutes for conventional glass cladding • Embodied energy of glass cladding 904 MJ/m2 • Centralised PV plant • Output 1200 kWh/kWp/year • Green field site • Foundations, perimeter fence, 200 m cabling • Connected to grid • Modules • 12% efficient • Production plant – annual production 2-5 MWp per year • Life of systems 25 years • Costs

31. Embodied primary energy in supplying 1 kWh of electricity to the point of use

32. Energy analysis factors for PV systems

33. Economic costs of supplying 1 kWh of electricity to the point of use

34. Calculating unit electricity costs for PV systems

35. Conclusions • In Europe there is a trade off between energy and economic viability • PV systems use significantly less primary energy than conventional electricity mixes, and associated resource savings and emission reductions • In Europe PV is significantly more expensive than conventional electricity systems • BiPVs offer cost reduction in energy and economic terms over centralised PV systems • Given dynamic nature of PV industry and expected future cost reductions, the economic benefit of BiPV is likely to be viable in the future