Life Cycle Metrics for Comparing
Alternative Electricity Generating
Technologies
David Spitzley and Gregory Keoleian
Center for Sustainable Systems
University of Michigan
InLCA Conference
Seattle, WA
September 23rd, 2003
The Electricity Debate
EU Greenhouse Emissions Up Second Year in a Row
– THE ELECTRICITY DAILY (May 14, 2003)
STUDY TOUTS NUCLEAR POWER AS WAY TO SLOW GLOBAL WARMING
– THE BOSTON GLOBE (July 30, 2003)
Free as the wind but not too cheap
– Financial Times(London) (July 19, 2003)
China's city-swamping Three Gorges dam project
– The Times(London) (May 31, 2003 )
Power plant debate pits clean air, cheap electricity
– The Atlanta Journal and Constitution(September 11, 2001 )
Farmers burned as green energy plant faces
export: £30 million power station goes bankrupt
after eight days, leaving growers high and dry
– The Guardian(London) (May 31, 2003)
It's clean and efficient but blighted
by link to death and destruction
– The Times(London) (September 2,2002)
EU WAR ON ACID RAIN 'THREATENS COAL JOBS'
– The Guardian(London)(September 8, 1997)
Key Issues and Metrics
• Issues
– Effective Resource
Use
– Clean Air and Water
– Availability of Land
– Economics
Key Issues and Metrics
• Issues
– Effective Resource
Use
– Clean Air and Water
– Availability of Land
– Economics
• Life Cycle Metrics
Net Energy Ratio
External Energy Ratio
Global Warming Potential
Acidification Potential
Land Use
Fuel Costs
Cost of Electricity
Societal Costs
Technologies Examined
Fossil Fuel Systems
Based on
Literature
CSS Research
Focus
Renewable Systems
Electricity Generating Technology Life
Cycle: Boundary Conditions
Fuel Acquisition
Material Acquisition
Fuel Processing
Material Processing
Fuel Transport
Technology Production/
Construction
Plant/Technology
Operation
Electricity to the Grid
Willow Biomass System
• Willow Short Rotation Forestry (SRF)
production system with:
– Direct-fire boiler(1)
– High pressure gasification(1)
– Low pressure gasification(2)
• Example Data
– Willow SRF Land Area: 13.6 odt/ha/yr
– Willow Price: $35.86/dry ton(3)
– Willow SRF Energy Use: 98.3 GJ/ha(4)
(1)Data source: EPRI/DOE, 1997
(2)Data source: Mann and Spath, 1997
(3)Farm gate price, ORNL Energy Crop County Level Database
(4)Seven harvest rotations
Photovoltaic System
• Building Integrated Photovoltaic (BIPV) modules
(including balance of system)
– Materials Acquisition
– Module Production
– Generation in 15 U.S. Cities:
• Results for the Pacific Northwestern U.S.
(Portland, OR) are discussed here.
• Example Data
– BIPV Array: 34 m2
– BIPV total capital requirement:
$16,000 (1999)
– Stabilized conversion efficiency:
6%
Biomass/Coal Co-Fire
• Systems Considered
– Operation of Dunkirk Power Plant Unit #1 (NY) with two
feed alternatives:
• Coal/Willow Biomass Blend
– 90% Coal (wt. basis)/ 10% Willow Biomass
• Coal/Wood Biomass Blend
– 90% Coal/ 9.5% Wood Residue/ 0.5% Willow
• Example Data
– Annual Operating Cost: $10.77/kW-yr(1)
– Heating Value (HHV):
• Coal: 30.6 MJ/kg
• Wood Residue: 18.3 MJ/odkg
• Willow: 19.8 MJ/odkg
(1)Relative to coal only operation; EPRI/DOE, 1997
Coal
• Systems Considered(1)
– Average Coal Plant
– New Source Performance Standards (NSPS) Plant
– Low Emission Boiler System (LEBS) Plant
• Example Data
– Land Requirements
• Coal mining: 4,015 tons/acre(2)
• Utility Plant: 320 acre(3)
– Coal Cost: $1.24/MMBtu(3)
(1) Plant operating data and life cycle inventory results provided by
Spath, Mann and Kerr, 1999
(2) Typical Appalachian region production: Energia, University of
Kentucky, 2002
(3) DOE, 1999
Natural Gas
• Systems Considered
– Natural Gas Combined Cycle(1)
• Example Data
– Economics
• Natural Gas Cost: $2.70/MMBtu(2)
• Operating Cost (non-fuel): $0.0032/kWh(2)
• Total Capital Requirement: $562/kW(2)
– Land Requirements
• Pipeline area requirements: 290 acre(3)
• Utility Plant: 100 acre(2)
(1) Plant operating data and life cycle inventory results
provided by Spath and Mann, 2000
(2) DOE, 1999
(3) Calculated from Spath and Mann, 2000 (2,486 pipe
miles)
Which Technologies Provide the Most
Effective Use of Energy Resources?
Net Energy Ratio =
Net System Electricity Generation
Total Life Cycle Fossil Energy Use
Fossil Energy
Input
Electricity
Output
Values >1 Do Not Violate 1st Law of Thermodynamics
Net Energy Ratio
Fossil Energy
Input
W
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PV
Which Technologies Provide the Most
Effective Use of Energy Resources?
14
12
10
8
6
4
2
0
Electricity
Output
Values >1 Do Not Violate 1st Law of Thermodynamics
W
(P
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SP
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a
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as
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BI
PV
(g CO2 eqv./kWh)
Which Technologies Generate the
Least Greenhouse Gas Emissions?
1200
1000
800
600
400
200
0
Based on 100 year potential values reported in IPCC,Third Assessment Report, 2001
W
(P
or
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ow an
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PV
AP (H+ mol eqv./kWh)
Which Technologies Most Effectively
Limit Acidification?
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
AP = Acidification Potential; Based on national average TRACI Characterization
Factors, EPA, 2002
Which Technologies Provide the Most
Effective Use of Land Resources?
• Life Cycle Area Required to Support
Washington State Electricity Consumption
(100,436 GWh)(1)
1. BIPV (1.37 ha-yr/GWh)(2)
2. Willow, Direct-Fire (55.3 ha-yr/GWh)
3. Willow, HP Gasifier (42.6 ha-yr/GWh)
4. Willow, LP Gasifier (41.1 ha-yr/GWh)
1
3
2
5. Coal/Wood Co-Fire (1.19 ha-yr/GWh)
6. Coal/Willow Co-Fire (6.26 ha-yr/GWh)
8. Coal, NSPS (1.05 ha-yr/GWh)
9. Coal, LEBS (0.87 ha-yr/GWh)
9
4
7. Coal, Average (1.16 ha-yr/GWh)
8
5
6
10
7
10. Natural Gas CC (0.07 ha-yr/GWh)
(1) Hypothetical example, does not account for regional differences in all data
(2) Data for Portland ,OR; existing building area required.
PV
Co
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al
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CC
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LE
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as
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al
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SP
S
10
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Av
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a
Co
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,
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as
ife
r
as
ifi
G
G
e
(cents/kWh)
12
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Co
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(P
or
t
W
ill
W
ill
W
ill
BI
Which Technologies Offer the
Lowest Costs?
Damage Cost (¢/kWh)
COE (¢/kWh)
8
6
4
2
0
COE = Cost of Electricity, Operating revenue requirement
Where are Generating Resources
Available?
States(1)
Hydro
(>1,000 MW capacity)
Hydro/Wind
Wind States(1)
(>400 W/m2 @ 50 m)
Poplar Biomass
States(1)
(> 10 ton/ha/yr)
Willow Biomass
States
(> 9 ton/ha/yr)
Willow/Wind
Hydro/Solar
Hydro/Willow
Solar States
(>5 kWh/m2/day)
• Renewable Energy Resource
Availability in the United States
Sources
Hydro: DOE, U.S. Hydropower Resource Assessment, 1998
Biomass: Klass, Biomass for Renewable Energy, Fuels, and
Chemicals, 1998
Solar: NREL, Solar Atlas, Annual Direct Normal Solar Radiation, 2002
Wind: NREL, Wind Resource Map
(1) To be examined in future study
What’s Next?
• Examination of additional electricity
generating technologies
– Hydroelectric
– Wind
– Nuclear
– Poplar Biomass
Key Resources
• Analysis Based On:
– Spath and Mann (2000) Life Cycle Assessment of a Natural Gas
Combined-Cycle Power Generation System, NREL
– Spath, Mann and Kerr (1999) Life Cycle Assessment of Coal-fired
Power Production, NREL
– Mann and Spath (1997) Life Cycle Assessment of a Biomass
Gasification Combined-Cycle System, NREL
– EPRI/DOE (1997) Renewable Energy Technology Characterizations
– DOE (1999) Market-Based Advanced Coal Power Systems
• Relevant CSS Publications:
– Heller, et al. (In Press) “Life Cycle Energy and Environmental
Benefits of Generating Electricity from Willow Biomass,” Renewable
Energy.
– Heller, Keoleian and Volk (2003) “Life Cycle Assessment of a Willow
Bioenergy Cropping System,” Biomass and Bioenergy, 25, 147-165.
– Keoleian and Lewis (2003) “Modeling the Life Cycle Energy and
Environmental Performance of Amorphous Silicon BIPV Roofing in
the US,” Renewable Energy, 28, 271-293.
Acknowledgements
• Contributing Research Staff:
– CSS
• Marty Heller
• Geoff Lewis
– NREL
• Margaret Mann
– SUNY Syracuse
• Timothy Volk
• Research funding provided by the United States
Department of Agriculture