ENV-2D02 Energy Conservation ENV-2D02 Energy Conservation 20062006

Energy Analysis & Energy Analysis &

Lifecycle AssessmentLifecycle Assessment

Energy AnalysisEnergy Analysis A method for calculating the total amount of primary energy required A method for calculating the total amount of primary energy required

to provide a good or serviceto provide a good or service Also called: energy budgeting, accounting & costing Also called: energy budgeting, accounting & costing Heyday - 1970sHeyday - 1970s

• Ian Boustead (1972) energy used in beverage containersIan Boustead (1972) energy used in beverage containers• 1979 Handbook of Industrial Energy analysis1979 Handbook of Industrial Energy analysis

Developed into Developed into Life cycle assessmentLife cycle assessment Life cycle energy analysisLife cycle energy analysis Embodied energyEmbodied energy

Life cycle energy analysis (LCEA) Life cycle energy analysis (LCEA) an approach in which all energy inputs to a product are accounted for, an approach in which all energy inputs to a product are accounted for,

not only direct energy inputs during manufacture, but also all energy not only direct energy inputs during manufacture, but also all energy inputs needed to produce components, materials and services needed inputs needed to produce components, materials and services needed for the manufacturing process. Early expression used for the approach for the manufacturing process. Early expression used for the approach is energy analysis.is energy analysis.

Can include an LCA of energy production Can include an LCA of energy production • eg electricity generation, biofuelseg electricity generation, biofuels

Or an LCA that is limited to energy criteriaOr an LCA that is limited to energy criteria

Not to be confused with life cycle costing (LCC)Not to be confused with life cycle costing (LCC)

A technique to quantify the financial costs of A technique to quantify the financial costs of a product throughout it’s lifetimea product throughout it’s lifetime

Does not usually include environmental Does not usually include environmental criteriacriteria external costs - costs to societyexternal costs - costs to society

Capital cost + operating cost + maintenance Capital cost + operating cost + maintenance + recycling + disposal+ recycling + disposal

Can be combined with energy analysis/LCACan be combined with energy analysis/LCA

Lifecycle energy analysisLifecycle energy analysis

extraction

manufacture

processing

use

transport

end of life

final disposal

reuse/recycling

waste heatenergy

Lifecycle assessmentLifecycle assessment

extraction

manufacture

processing

use

transport

end of life

final disposal

reuse/recycling

waste heat

emissions

energy

materials

waste

Functional unit

water

Functional unitFunctional unit Relates to the function a product or service will Relates to the function a product or service will

deliverdeliver Energy analysisEnergy analysis

A unit of delivered energy (kWh)A unit of delivered energy (kWh) Energy to heat a home for a yearEnergy to heat a home for a year Energy to build a nuclear power station or a wind Energy to build a nuclear power station or a wind

turbine or a houseturbine or a house• embodied energyembodied energy

Lifecycle assessmentLifecycle assessment Washing machine – 5 kg clothesWashing machine – 5 kg clothes Packaging for 1 litre milkPackaging for 1 litre milk Disposal of Norfolk’s wasteDisposal of Norfolk’s waste

Lifecycle assessment stagesLifecycle assessment stagesFour major stages Four major stages Goal and scope definition Goal and scope definition

defines the purpose defines the purpose extent of the study – boundariesextent of the study – boundaries descriptiondescription functional unit functional unit

Life cycle inventoryLife cycle inventory detailed compilation of all environmental inputs and outputs for detailed compilation of all environmental inputs and outputs for

each stage of the life cycle each stage of the life cycle results in a long list of resources and emissions, usually in results in a long list of resources and emissions, usually in

incompatible unitsincompatible units Life cycle impact assessmentLife cycle impact assessment

quantifies and aggregates the relative importance of all quantifies and aggregates the relative importance of all environmental burdens obtained in the LCI environmental burdens obtained in the LCI

Interpretation of the resultsInterpretation of the results

Problems with LCA & LCEAProblems with LCA & LCEA Some impacts can’t be measureSome impacts can’t be measure Site specific vs average analysisSite specific vs average analysis Results of lifecycle inventory (LCA)Results of lifecycle inventory (LCA)

long lists of environmental impacts all in different unitslong lists of environmental impacts all in different units decision making process decision making process

Assumptions: results can be different for similar studiesAssumptions: results can be different for similar studies Boundary issuesBoundary issues Allocation problemsAllocation problems Just a snapshot of the environmental impactsJust a snapshot of the environmental impacts

does not easily take long term effects into considerationdoes not easily take long term effects into consideration Split between the scientists and engineers who are trying to develop Split between the scientists and engineers who are trying to develop

a scientifically-defensible tool and the business managers and a scientifically-defensible tool and the business managers and policy makers who are trying to make sound environmental policy makers who are trying to make sound environmental decisions decisions

LCA of Construction and Demolition Waste (EPSRC)LCA of Construction and Demolition Waste (EPSRC)

Indicator /problem area

landfill landfill/recycle

all reuse/recycle

reuse Units (per tonnedemo. waste)

Raw material 1.05 0.56 0.39 0.06 0.05 tWater use 352.84 194.68 135.89 27.08 17.64 lPrimary energy 173.33 159.58 120.71 93.99 41.51 MJLandfill volume 0.51 0.27 0.19 0.03 0.03 m3 netJobs 0.07 0.06 0.06 0.05 0.04 person-daysCasualties 1.7 x 10-4 1.1 x 10-4 9.3 x 10-5 5.6 x 10-5 5.2 x 10-5 no.Land use 8 10 11 11 9 scoreVisual 9 12 14 14 11 scoreNoise 8 11 13 13 10 scoreParticulates 0.02 0.02 0.01 0.01 0 kgGlobal warming 12.6 11.38 8.59 6.56 2.92 kg CO2 equiv.Nutrification 0.02 0.02 0.01 0.01 0.01 kg phosphate

equiv.Acidification 0.16 0.14 0.11 0.08 0.04 kg SO2 equiv.Oxidantformation

6.7 x 10-6 7.2 x 10-6 5.5 x 10-6 4.8 x 10-6 2.1 x 10-6 kg ethyleneequiv.

Human toxicity,air

0.18 0.16 0.12 0.09 0.04 kg

Human toxicity,water

1.1 x 10-5 1.1 x 10-5 8.3 x 10-6 7.1 x 10-6 3.1 x 10-6 kg

Aquaticecotoxocity

7.2 x 10-4 7.2 x 10-4 5.5 x 10-4 4.7 x 10-4 2.0 x 10-4 kg

Road transport 6.05 6.57 4.53 3.74 0.35 kmMalodorous air 1.6 x 10-11 1.0 x 10-11 8.2 x 10-12 4.3 x 10-12 3.8 x 10-12 m3

Lifecycle impact assessmentLifecycle impact assessment Two mandatory elementsTwo mandatory elements

classification classification • assigns the inventory results to different impact categories such as assigns the inventory results to different impact categories such as

global warmingglobal warming characterisation characterisation

• calculates a category indicator result for each impact category using calculates a category indicator result for each impact category using characterisation factors such as carbon dioxide equivalents characterisation factors such as carbon dioxide equivalents

Two optional elementsTwo optional elements normalisation normalisation

• Benchmarks the aggregated emissions against a known total effect, Benchmarks the aggregated emissions against a known total effect, e.g. average annual European emission the total national emissionse.g. average annual European emission the total national emissions

• Normalization enables you to see the relative contribution from the Normalization enables you to see the relative contribution from the material production to each already existing effect. material production to each already existing effect.

weighting weighting • A range of methods used to explore the relative importance of the A range of methods used to explore the relative importance of the

aggregated emissionsaggregated emissions

Weighting the relative Weighting the relative importance of criteriaimportance of criteria

Distance to targetDistance to target Panel methodPanel method

ExpertsExperts Decision makersDecision makers Environmental groupsEnvironmental groups General public General public

Economic valuation Economic valuation

A set of valuation factors that is widely A set of valuation factors that is widely acceptable has not yet been establishedacceptable has not yet been established

Euros per tonne carbon

Boundary problemsBoundary problems

extraction

manufacture

processing

use

end of life

final disposal

reuse/recycling waste heatenergy

embodied energy

LCA/ LCEA

‘Cradle to grave’

‘Cradle to gate’

Geographic boundariesGeographic boundaries

More boundary problems: More boundary problems: depth of studydepth of study

First orderFirst order Direct inputs into product Direct inputs into product

manufacture manufacture Energy that made the bricks for a Energy that made the bricks for a

househouse Second orderSecond order

Inputs into manufacture of Inputs into manufacture of machines that manufacture the machines that manufacture the product product

Energy used to made the machine Energy used to made the machine that manufactured the bricks that manufactured the bricks

Third orderThird order Energy that made the machines, Energy that made the machines,

that made the machines that that made the machines that manufactured the bricks!manufactured the bricks!

and more boundary problems ……. and more boundary problems ……. extent of analysisextent of analysis

Energy onlyEnergy only Simple LCA Simple LCA

eg carbon emissionseg carbon emissions

Full LCAFull LCA Time consuming & Time consuming &

expensiveexpensive Data availabilityData availability

Embodied energyEmbodied energy

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

Embodied energyEmbodied energy

Does not refer to the energy available or inherent in a material or product

E.g. the energy recovered by burning a productE.g. the energy recovered by burning a product Could be called “Cumulative Energy Demand” - the sum of all the Could be called “Cumulative Energy Demand” - the sum of all the

energy inputs into a product system energy inputs into a product system

‘‘Embedded energy’ also used but not really correctEmbedded energy’ also used but not really correct Embedded generation is electricity generation (eg CHP) which is Embedded generation is electricity generation (eg CHP) which is

connected to a distribution network rather than to the high voltage connected to a distribution network rather than to the high voltage National Grid.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

Elements of embodied energyElements of embodied energy

Electricity (delivered)Electricity (delivered) Energy losses in electricity productionEnergy losses in electricity production

fuel conversion at power plant (typically 60-70% of primary fuel fuel conversion at power plant (typically 60-70% of primary fuel input) input)

transmission and distribution losses (typically 2-8%) transmission and distribution losses (typically 2-8%) Fuel extraction, processing and delivery Fuel extraction, processing and delivery

Energy consumption delivering fuel for use in power plants, Energy consumption delivering fuel for use in power plants, transport equipment and industrial plant (typically 2-10%) transport equipment and industrial plant (typically 2-10%)

Process heatProcess heat Transport Transport FeedstockFeedstock

fuel used in situation where they are not directly oxidized such 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. as oil and gas in plastics, carbon in cokes and pitch and so on.

Energy in capital equipment Energy in capital equipment

Embodied energy of building materialsEmbodied energy of building materials

Energy consumption for a typical house & Energy consumption for a typical house & low energy houselow energy house

(Crane Environmental Ltd, 2000)(Crane Environmental Ltd, 2000)

Typical house

Low energy house

Combines LCEA and LCC:Combines LCEA and LCC:Financial & energy payback for a solar water Financial & energy payback for a solar water

pre-heater pre-heater (Crane Environmental Ltd, 2000)(Crane Environmental Ltd, 2000)

Example of simple LCAExample of simple LCA

Life cycle carbon dioxide emission figures for Life cycle carbon dioxide emission figures for various generation technologiesvarious generation technologies

(Vattenfall, 1999)(Vattenfall, 1999)

g/kWh CO2 Japan Sweden Finlandcoal 975 980 894gas thermal 608 1170 -gas combined cycle 519 450 472solar photovoltaic 53 50 95wind 29 5.5 14nuclear 22 6 10-26hydro 11 3 -

More complex analysis:More complex analysis:LCA & lifecycle cost models for building LCA & lifecycle cost models for building

construction developed by Hong Kong Govt.construction developed by Hong Kong Govt.

Example of energy analysis of recycling Example of energy analysis of recycling broken glassbroken glass

Energy requirement for melting raw material Energy requirement for melting raw material with differing amounts of recyclingwith differing amounts of recycling

Energy requirements for raw production for Energy requirements for raw production for 1 unit of new material1 unit of new material

Energy and economic evaluation of building-Energy and economic evaluation of building-integrated photovoltaicsintegrated photovoltaics ( (Oliver & Jackson, 1999Oliver & Jackson, 1999))

Energy viabilityEnergy viability 1970s – suggestion that 1970s – suggestion that

photovoltaics were not viable in photovoltaics were not viable in energy termsenergy terms

More recent studies – energy More recent studies – energy payback terms fraction of payback terms fraction of lifetime & likely to falllifetime & likely to fall

This study compares: This study compares: European electricity mix European electricity mix centralised PV centralised PV building integrated PV (PiPV) building integrated PV (PiPV)

Energy and economic evaluation of building-Energy and economic evaluation of building-integrated photovoltaicsintegrated photovoltaics ( (Oliver & Jackson, 1999Oliver & Jackson, 1999))

MethodologyMethodology Functional unit 1 kWh delivered electricityFunctional unit 1 kWh delivered electricity Compare costs in energy & economic termsCompare costs in energy & economic terms

• Energy analysis & lifecycle costs (p/kWh)Energy analysis & lifecycle costs (p/kWh) Average EU mix, Central PV, BiPV, Average EU mix, Central PV, BiPV,

Building integrated PVs (Zicer) has two functionsBuilding integrated PVs (Zicer) has two functions Generates electricity – displaces conventional energy Generates electricity – displaces conventional energy

systemsystem Weatherproofing function – displaces conventional Weatherproofing function – displaces conventional

cladding system cladding system Net BiPVNet BiPV

AssumptionsAssumptions BiPV systems BiPV systems

Output 850 kWh/kWp/yearOutput 850 kWh/kWp/year Electricity produced is consumed within buildingElectricity produced is consumed within building Building has high base load demandBuilding has high base load demand

• Hospital, universityHospital, university• No export to the gridNo export to the grid

BIPV cladding substitutes for conventional glass claddingBIPV cladding substitutes for conventional glass cladding• Embodied energy of glass cladding 904 MJ/m2Embodied energy of glass cladding 904 MJ/m2

Centralised PV plantCentralised PV plant Output 1200 kWh/kWp/yearOutput 1200 kWh/kWp/year Green field siteGreen field site Foundations, perimeter fence, 200 m cablingFoundations, perimeter fence, 200 m cabling Connected to gridConnected to grid

ModulesModules 12% efficient12% efficient Production plant – annual production 2-5 MWp per yearProduction plant – annual production 2-5 MWp per year Life of systems 25 yearsLife of systems 25 years

CostsCosts

Embodied primary energy in supplying Embodied primary energy in supplying 1 kWh of electricity to the point of use1 kWh of electricity to the point of use

0

2

4

6

8

10

12

14

Av euromix

centralPV

BiPV Net PV

pri

mar

y en

erg

y in

pu

t (M

J) balance of system

modules

electricitygeneration

transmission &distribution

Energy analysis factors for PV systemsEnergy analysis factors for PV systems

Central PV BiPV Net BiPVEnergy embodied (KJ) 4.2 2.9 2.5Energy saved (MJ) 13.2 13.2 13.2Energy return on investment 3.2 4.5 5.2System lifetime (years) 25 25 25Energy payback time (years) 7.9 5.5 4.8Net energy balance (%) 68 78 81

Economic costs of supplying 1 kWh of Economic costs of supplying 1 kWh of electricity to the point of useelectricity to the point of use

0

10

20

30

40

50

60

70

80

90

Av euro mix central PV BiPV Net PV

un

it e

lect

rici

ty c

ost

s (p

/kW

h)

electricity generation

transmission & distribution

Calculating unit electricity Calculating unit electricity costs for PV systemscosts for PV systems

Central PV BiPV Net BiPVCapital cost (£/kWp) 8610 67780 3240Discount rate (%) 8 8 8Project life-time (years) 25 25 25Capital cost repayment p.a. (£/kWp) 807 635 304Annual system output (kWh) 1200 850 850Buy back price (p/kWh) 67 75 36

ConclusionsConclusions

In Europe there is a trade off between In Europe there is a trade off between energy and economic viabilityenergy and economic viability

PV systems use significantly less primary PV systems use significantly less primary energy than conventional electricity mixes, energy than conventional electricity mixes, and associated resource savings and and associated resource savings and emission reductionsemission reductions

In Europe PV is significantly more expensive In Europe PV is significantly more expensive than conventional electricity systemsthan conventional electricity systems

BiPVs offer cost reduction in energy and BiPVs offer cost reduction in energy and economic terms over centralised PV systemseconomic terms over centralised PV systems

Given dynamic nature of PV industry and Given dynamic nature of PV industry and expected future cost reductions, the expected future cost reductions, the economic benefit of BiPV is likely to be economic benefit of BiPV is likely to be viable in the futureviable in the future