U.S. power plant emissions down

A shift to new technology creates more energy, releases fewer pollutants

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Caitlin Rockett

A new study shows that natural gas power plants that use a
new technology to extract more energy from the fuel release significantly less
carbon dioxide than coal-fired plants do. These “combined cycle” natural gas
power plants used two heat engines to convert more of the heat into electrical
energy.

The study, conduced by researchers from NOAA’s Cooperative
Institute for Research in Environmental Sciences at the University of Colorado
Boulder, was published in the journal Earth’s
Future
in January.

“Since more and more of our electricity is coming from these
cleaner power plants, emissions from the power sector are lower by 20, 30, even
40 percent for some gases since 1997,” said lead author Joost de Gouw, an
atmospheric scientist with NOAA’s Cooperative Institute for Research in
Environmental Sciences (CIRES) at the University of Colorado Boulder, in a
university press release.

Using emissions data from across the country, the research
team compared pollutants from different types of power plants by calculating
emissions per unit of energy produced between 1997 and 2012. Calculations showed
that coal-based power plants emitted 32 ounces of CO2 per kilowatt
hour of energy produced, while natural gas plants emitted 19 ounces of CO2.
Combined cycle natural gas plants emitted only 15 grams of CO2.

The team also found that between 1997 and 2012, the United
States reduced electrical energy produced from coal and increased energy
produced from combined cycle natural gas plants, resulting in 23 percent less
CO2 being released into the atmosphere.