Thursday, January 16, 2014

Study Confirms Gas Power Plants Cleaner Than Coal Plants (I Think We Already Knew This)

A soon to be released study comparing emissions from power plants since 1997 confirmed that overall emissions of carbon dioxide and other pollutants have decreased significantly as a result of increased natural gas use over coal, reported Scientific American last week.  The components of this conclusion are widely known, but it's nice to have a reminder that quantifies the difference between coal and natural gas.

From the study, on average:
  • Coal-fired plants emit 32 oz. of CO2 per kilowatt hour (kWh) of power
  • Gas-fired plants emit 19 oz of CO2/kWh
  • Combined cycle gas plants emit 15 oz of CO2/kWh
  • Gas-fired plants emit 7% of the nitrogen oxides of a coal plant (easier to scrub in gas plant)
  • Gas-fired plants emit 0.2% of the sulfur dioxide of a col plant (not much sulfur in gas)

This study confirms the oft-cited rule of thumb that gas plants emit half the carbon dioxide of coal plants and only a small fraction of the smog-creating chemicals.

Environmentalists are quick to argue that the study doesn't consider methane leakages or fuzzy threats from hydraulic fracturing, but it also doesn't consider the loss of CO2-consuming vegetation and other environmental damage from strip mining and mountaintop removal in search of coal.  

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