by Shane Henson — May 9, 2012—A new approach to assessing greenhouse gas emissions from coal, wind, solar and other energy technologies paints a much more precise picture of cradle-to-grave emissions and should help sharpen decisions on what new energy projects to build.
The method—a harmonization conducted by the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) of widely variant estimates of greenhouse gas emissions—is being heralded as an important step forward in life cycle assessments that paints a clearer picture of the environmental penalties and benefits of different technologies.
According to the NREL, which is the only federal laboratory dedicated to the research, development, commercialization and deployment of renewable energy and energy efficiency technologies, its analysts looked at more than 2,000 studies across several energy technologies, applied quality controls, and greatly narrowed the range of estimates for greenhouse gas emissions.
The harmonization found that cradle-to-grave greenhouse gas emissions from solar photovoltaics are about five percent of those from coal; that wind and solar are about equal in emissions; and that nuclear energy is on a par with renewable energy.
And the analysis succeeded in narrowing the huge range of estimates, says NREL—in some cases by 80 to 90 percent—to a robust median, improving precision and giving stakeholders a much clearer look at the likely environmental impacts of various projects.
NREL’s findings appear in six articles and an editorial in the May special supplemental issue on Meta-Analysis of Life Cycle Assessment (LCA) of the Journal of Industrial Ecology.
