Post on 26-Dec-2015
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