Life Cycle Assessment
Harmonization
The U.S. Department of Energy
enlisted NREL to review and "harmonize" life cycle assessments of
electricity generation technologies. Hundreds of assessments have been
published, often with considerable variability in results. These variations in
approach, while usually legitimate, hamper comparison across studies and
pooling of published results.
By harmonizing this data, NREL
seeks to reduce the uncertainty around estimates for environmental impacts of
renewables and increase the value of the assessments to the policymaking and
research communities: http://www.nrel.gov/analysis/sustain_lcah.html
Comparison of Harmonization
Impacts on Pressurized Water Reactor and Boiling Water Reactor Technologies
Assuming consistent performance characteristics, the
median LC GHG emissions estimates were nearly identical for PWR and BWR
technologies after harmonization. The median life cycle GHG emission estimates
for PWR and BWR technology types are 14 and 21 g CO2eq/kWh, respectively, as
published, and 12 and 13 g CO2eq/kWh, respectively after harmonization.
Comparison of Harmonization
Impacts on Onshore to Offshore Wind Technologies
The median published life cycle GHG emission estimates
for onshore and offshore technology types are both 12 g CO2eq/kWh and 11 g
CO2eq/kWh after harmonization. This similarity, combined with the tight
distribution for both technology types, suggests that the two technology types
may not have significantly different life cycle GHG emissions.
Comparison of Harmonization
Impacts on Specific Photovoltaic Technologies
The median as-published life cycle GHG emissions estimate
for c-Si PV is 57 g CO2eqkWh; the harmonized median is 45 g CO2eq/kWh.
Harmonization reduced the IQR from 44-73 g CO2eq/kWh to 39-49 g CO2eq/kWh, a
reduction of 62%. Additional analysis comparing mono-Si and multi-Si
technologies, and ground-mounted with roof-mounted systems suggest that these
system differences are not key factors in lifecycle GHG emissions from c-Si PV.
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You can run by a LFTR design, or for that matter GE Hitachi's PRISM reactor and know that they only involve a fraction of the material content of an LWR of equivalent power - and, by extension, assume that only a fraction of the energy of construction is used.
