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Life Cycle Assessment Harmonization

Life cycle assessment (LCA) harmonization helps lenders, utility executives, and lawmakers get the best, most precise information on greenhouse gas emissions from various sources of energy. LCA has been used to estimate and compare GHG emissions from utility-scale power systems for three decades, often with considerable variability in results. Harmonization provides more exact estimates of greenhouse-gas emissions for renewable and conventional electricity generation technologies, clarifying inconsistent and conflicting estimates in the published literature and reducing uncertainty.

Highlights of Recent Studies

Chart that compares published and harmonized life cycle greenhouse gas emissions. For help reading this chart, please contact the webmaster.

Comparison of as-published and harmonized life cycle greenhouse gas emission estimates for selected electricity generation technologies.

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NREL's Life Cycle Assessment Harmonization Project evaluated the LCA literature on solar (both photovoltaic and concentrating solar power), wind, nuclear, natural gas and coal technologies. Overall, this study shows that:

  • The harmonization process increased the precision of life cycle GHG emission estimates in the literature while having little effect on the median, or central tendency, of these estimates.
  • From cradle-to-grave, coal-fired energy releases about 20 times as much greenhouse gas into the atmosphere per kilowatt-hour as solar, wind, and nuclear energy, and about double those for electricity generated from conventionally and unconventionally produced natural gas.

To learn more about this study, please visit the Life Cycle Assessment Harmonization webpage.

Find out more about NREL's LCA Harmonization approach (tools, data):

For more details on NREL's LCA harmonization analyses, see:

For questions on NREL's LCA Harmonization Project, contact Garvin Heath via our Webmaster page.