New Study: Natural gas-fired power plants cleaner than coal-fired plants
Jan. 9, 2014
Joost de Gouw
Natural gas combined with new technology is helping power plants
create more energy and at the same time release less greenhouse gases than
coal-fired power plants do, according to a joint study from CU-Boulder’s
Cooperative Institute for Research in Environmental Sciences and the National
Oceanic and Atmospheric Administration.
The emissions of CO2, sulfur and nitrogen oxide have dropped
significantly in the past decade, says atmospheric scientist and lead author
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 44 percent.” (:30)
Since 1997 electric energy produced from coal has dropped from 83
percent to 59 percent, replaced by natural gas. And the biggest change in
producing less greenhouse gases is the creation of what is called “combined
cycle” natural gas power plants,1 says de Gouw. The process uses the exhaust
of one heat engine as the heat source for another, thus extracting more
useful energy from the heat and increasing the systems overall efficiency.
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)
Not only does the reduction of greenhouse gases in the atmosphere
from power plants help slow climate change but it also helps people to
breathe healthier air, says de Gouw. Nitrogen oxides and sulfur dioxide can
cause respiratory disease.
CUT 3 “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.” (:18)
De Gouw says the new study is limited to pollutants emitted during
energy production and measured at stacks. It does not address levels of
greenhouse gases and other pollutants that leak into the atmosphere during
fuel extraction. He says his colleagues are actively looking at the impact of
natural gas extraction on air quality but there are no final answers yet.
CUT 4 “So in Colorado and elsewhere there is much concern about the
environmental effects of natural gas production and we are actually looking at
those but this study looks at the environmental effects of the use of natural
gas. (:16) And when the gas is used for electric power generation there are
actually significant benefits and those need to be weighed against the
potential disadvantages of the production of gas.” (:30)
De Gouw says it’s important to investigate the total atmospheric
consequences of shifting energy use. To do that, he says scientists need to
continue collecting data from all aspects of energy exploration, production
and use.
-CU-