Chapter 5 Powerpoint from Energy for Sustainability


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Energy Balance

Eo = energy output (e.g., useful energy)

Ed = direct energy input (e.g., fuel) Ei = indirect energy input

Eic = indirect energy continuous (e.g., energy to produce fuel)

Eiot = indirect energy one-time (e.g., energy to make device)

ts = system life (used to convertE

iot to annual energyE

iot/ts)


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Energy Analysis Metrics







iot/ts)


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10E

EefficiencyconversionDirect

d

o eLe!L!

1*0

EE

Eo*efficiencyenergyOverall

id

eLe

!L!

Energy Analysis Metrics: Efficiency


Ed = direct energy input (e.g., fuel)

Ei = indirect energy input Eic = indirect energy continuous (e.g., energy to produce fuel)


ts = system life (used to convert Eiot to annual energy Eiot/ts)


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Metrics: Net Energy

i

o

EEEROIinvestmentenergyonreturnEnergy !!

o

iot

E

EEPBTmepayback tiEnergy !!

io EEvalueenergyNet !







iot/ts)


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Metrics: Focus on Carbon, Petroleum

FFid

o

)E(E

EFFRratiofuelFossil

!!

o

Petroid

E)E(EPIRratioinputPetroleum !!


Ed = direct energy input (e.g., fuel)

Ei = indirect energy input



ts = system life (used to convert Eiot to annual energy Eiot/ts)


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EROI

forvarious

energy

sources


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Compare ethanol to gasoline:EROI not as important and Net Fossil Fuel


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Farrell, et al., Science, 2006

Net Energy & Petroleum Input


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Energy Input and Carbon Emissions


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Getting Energy Use Data

Billing meters (e.g., gasoline pumps, electric, natural gas meters)

Monitor run-time:

energy used = run-time (hrs) x energy/time

Submeters, data loggers


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Dataloggers


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Economic Analysis

Economic value of energy: price


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Volatility: Price ofGasoline in U.S., 1999-2007


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Time value of money

$100


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Time-value doesnt matter much for short time

periods and low discount rates

Present value of $100 Future dollars:a. d=4%, n=10 years

b. d=1%, n=10 years

c. d=10%, n=0.5 years

d. d=10%, n=10 years


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Simple Payback Period (SPP)

Time to payback initial cost with energy savings

IC = initial cost (or cost difference when comparing

options), $AES = annual energy savings, energy units/year

Pr = energy price, $/energy unit

(years)x PrE

IC

PPperiodpaybackimple !!


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Cost of Conserved Energy (CCE)

Cost per unit energy saved that can becompared to existing rates

unit)$/energy(S

m&o

1-d)-(1d)d(1(C F)FactorRecoveryCapital n

n

!

AES

m&oC

RF

xIC

CCEenergyconservedofCost

!!

CRF takes one-time payment and spreads it out over thelifetime (n) of the measure based on a discount rate (d)


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OtherEconomic Factors

n)d1(

1(P F)FactorValuePresent

!

n

n

d)d(1

1-d)-(1

(UPVF)FactorValuePresentUni orm !


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OtherEconomic Measures


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SPP and Market Penetration


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Conservation Supply Curve (CSC):plots cost per unit saved v. cumulative savings


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CSC for U.S. electricity, 1990:each step is an efficiency measure


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Economic Analysis Spreadsheet


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Environmental Analysis

Energy Use Impact/energy Impact


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Electricity depends on location


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Carbon

FootprintCalculator


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Calculating Emissions and Offsets

Input energy use, spreadsheet calculatescarbon emissions and green tags and treesto plant to offset emissions.

Chapter 5 Powerpoint from Energy for Sustainability

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Transcript of Chapter 5 Powerpoint from Energy for Sustainability