Stuck On Fossil Fuels | June 4, 2012 Issue - Vol. 90 Issue 23 | Chemical & Engineering News
Volume 90 Issue 23 | p. 27
Issue Date: June 4, 2012

Stuck On Fossil Fuels

The U.S. gets 70% of its electricity from fossil fuels and most of its pollution from old coal-fired power plants
Department: Government & Policy | Collection: Sustainability
News Channels: Environmental SCENE
Keywords: coal, electricity, natural gas, GAO, air pollution, Carbon Dioxide, Sulfur Dioxide, Nitrogen Oxides

The U.S. is deeply dependent on fossil fuels for its electricity. According to a recent government report that parses the nation’s electricity sources and air pollution, 70% of today’s electricity comes from natural gas and coal power plants, and nearly half of that electricity is generated by coal-fired power plants in operation for more than 30 years, long before pollution control devices were required.

Most of these plants continue to operate without modern controls, says the report by the Government Accountability Office, the investigative arm of Congress. It was requested by Sen. Sheldon Whitehouse (D-R.I.), a member of the Senate Environment & Public Works Committee. Whitehouse is concerned about air pollution entering his state of Rhode Island from old, coal-fired power plants operating in the Midwest, as well as the confusion over air pollution sources, according to a personal aide.

The report looks at plants operating in 2010 and finds that about 47% of electricity comes from coal-fired power plants and 23% from natural gas units. These fossil-fuel-based facilities generate nearly all emissions of sulfur dioxide, nitrogen oxides, and carbon dioxide from power plants, the report states.

It finds that, compared with natural-gas-fired power plants, coal-based units produce 90 times as much SO2, twice as much CO2, and more than five times as much NOx per unit of electricity. The report also determines that most pollution from coal-fired facilities comes from plants that the study classifies as old—that is, from facilities that began operating before 1978.

SO2 and NOx have been linked to respiratory illnesses and acid rain. The two compounds, the report notes, create fine particles that contribute to premature death, aggravated asthma, and chronic bronchitis. Ozone generated from NOx inflames lung tissue and increases susceptibility to bronchitis and pneumonia. CO2 is the primary anthropogenic greenhouse gas contributing to climate change.

In total, GAO determined that 3,443 fossil-fuel-based power plants were operating in the U.S. in 2011. The report classifies as new those that began operating in 1978—the year when the Clean Air Act provisions kicked in—and the rest as old. Under the law, power plants that began operating in 1978 were to install pollution control equipment. For the old plants, the law required modern emissions controls only when a plant conducted a large modification. Many old plants have chosen not to make modifications and, therefore, have not installed new pollution equipment.

The report classifies 1,485 of the operating fossil-fuel-based plants, or 43%, as old. This group produces about 45% of all fossil-fuel-generated electricity. Coal-fired power plants make up 93% of this group.

These old units contributed 75% of all U.S. fossil-fuel-generated SO2 emissions, 64% of NOx emissions, and 54% of CO2 emissions in 2010, according to the report. Only 25% of these old units had SO2 controls, and 14% had effective NOx controls.

The report also looks at power plant efficiencies, which is important because efficiency and CO2 emissions are inversely related. The report finds little improvement in efficiency between 1950 and 1990. After 1990—when more natural gas units came on-line—GAO reports a 53% decline in the amount of CO2 released, from 2,144 lb per megawatt-hour to 1,016 lb per MWh.

The impact of pollution from old coal-fired power plants varies, however. Some regions of the U.S. are more dependent on fossil-fuel-based power plants than others. For instance, in the mid-Atlantic and Great Lakes regions, older fossil-fuel-based units generate 64% and 71%, respectively, of all fossil-fuel-generated electricity. Nearly all these units burn coal.

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