One of the giant solar receivers at BrightSource Energy's Ivanpah… (Mark Boster / Los Angeles…)
The amount of carbon dioxide emitted from energy production declined in the U.S. in 2011 -- the third time in four years and the fourth time in the last six years that has happened, the Energy Department said Tuesday.
As has been the case in previous years, there wasn't necessarily a lot of good economic news behind the positive result of reduced emissions.
The Energy Department, for example, cited slower economic growth as one factor in the 2.4% drop in energy-related carbon dioxide emissions last year.
During the global recession in 2008 and 2009, for example, carbon dioxide emissions from energy production in the U.S. fell by 10%. In 2011, high gasoline prices also resulted in Americans putting in fewer miles on the road.
Still, the Energy Department found it noteworthy that the 2011 decline in carbon emissions came during a period of economic growth, with U.S. gross domestic product rising by 1.8% that year.
"Because the decline in CO2 emissions occurred in a growing economy," the Energy Department said, "the carbon intensity of the economy fell. This was mainly a result of using less energy or, in some cases, using less carbon-intensive energy, to achieve the same economic output."
The mild winter of 2011 was a factor, reducing the amount of energy needed to warm offices and homes, but the Energy Department also cited a significant shift to less carbon-intensive energy production.
"Electric power generation from natural gas, the least carbon intensive of the fossil fuels, increased by 3%, while generation from coal declined by 6%," the department said.
"Natural gas has approximately one-half the carbon of coal. Power generation from renewable sources also continued to rise, mostly because of record-breaking supplies of hydroelectricity and increasing generation from wind, solar and other renewable sources," it said.
The U.S. still has a long way to go in reducing its carbon footprint, however. The 2.4% decline in 2011 still meant that the U.S. generated more than 5.47 billion metric tons of carbon dioxide that year.
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