“Combined cycle technology” lowers power plant emissions
June 3, 2014
Joost de Gouw
As the political debate continues over President Obama’s proposal to
force a 30 percent cut in carbon dioxide emissions from 2005 levels by the
year 2030, one practical question being asked is do we have the technology
to reach that goal?
One recent study found that new technology being used in natural
gas-fired plants resulted in reduced CO2 levels, harmful gases that create
ozone and fine particles compared to coal-fired plants, says CU-Boulder
atmospheric scientist Joost de Gouw (YOOST D-GOW).
CUT 1 “Over the past 10 years or so a much larger fraction of our electric
power is now generated from natural gas with combined cycle technology.
(:10) And because these plants are more efficient and are cleaner the
emissions of CO2 have come down by 23 percent, the emissions of nitrogen
oxides have come down 40 percent and the emissions of sulfur dioxide from
power plants have come down by 44 percent.” (:30)
De Gouw is the lead author of a study from the Cooperative Institute
for Research in Environmental Sciences, a joint institute of CU-Boulder, and
the National Oceanic and Atmospheric Administration published earlier this
year. The study looked at how “combined cycle technology” and natural gas
are helping to produce more energy and produce less greenhouse gases.
CUT 2 “We were surprised to see how rapidly these new power plants that
use natural gas and combined cycle technology have come online and also
how relatively clean they are. (:14) These changes have benefits for climate
change but also for air quality. Ozone and fine particles that are formed from
nitrogen oxides and sulfur emissions are harmful to our health. So these are
very positive changes.” (:30)
“Combined cycle technology” uses the exhaust heat of one engine as
the heat source for another, extracting more useful energy from the heat and
increasing the systems overall efficiency.
According to de Gouw, for U.S. power plants between 1997 and 2012,
the fraction of electric energy in the United States produced from coal
gradually decreased from 83 percent to 59, and the fraction of energy from
combined cycle natural gas plants rose from none to 34 percent. To read
more about the study go to
http://www.colorado.edu/news/releases/2014/01/09/new-study-us-powerplant-emissions-down.
-CU-