US power plants cut emissions from nitrous oxides (NOx), sulfur dioxide (SO2) and CO2 in 2011 even as overall electricity generation increased, according to data from the Energy Information Administration and the EPA.
In 2011, power plant NOx and SO2 emissions were 70 percent and 72 percent lower, respectively, than they were in 1990 when Congress passed major amendments to the Clean Air Act, the report says. Additionally, since 1990, power plant CO2 emissions have increased by 20 percent, although CO2 emissions declined 7 percent from 2008 through 2011.
The Benchmarking Air Emissions report is the ninth in a series that analyzes the latest emissions data from the 100 largest power producers in the US. In 2011, the top 100 power producers together accounted for 86 percent of the electricity produced, the report says. These companies emitted approximately 4.1 million tons of SO2, 1.7 million tons of NOx, 25 tons of mercury, and 2.1 billion tons of CO2 in aggregate.
Ceres, NRDC, Entergy Corporation, Exelon, Pacific Gas and Electric Company, PSEG, Tenaska and Bank of America sponsored the report, which M.J. Bradley & Associates authored.
Nationwide, five power producers — American Electric Power, Duke Energy, FirstEnergy, Southern Company and Tennessee Valley Authority — generate 25 percent of overall electric sector CO2 emissions, though some of these producers and others have significantly reduced emissions in recent years. For example, AEP reduced its total SO2 emissions by 52 percent between 2000 and 2011, from 1.1 million tons to just over half a million tons, primarily by adding scrubbers to approximately 7,900 MW of coal-fired generating capacity, the report says.
Southern Company reduced total SO2 emissions by 63 percent while increasing overall generation 8 percent between 2000 and 2011 by bringing online approximately 14,000 MW of natural gas-fired capacity during the same period. Meanwhile, NextEra Energy added more than 20,000 MW of wind, solar, and natural gas-fired generating capacity between 2000 and 2011, and nearly doubled its total power generation, driving down its CO2 emissions rate from 1,023 to 603 pounds per MWh, a 41 percent improvement.
Among the top 100 power producers, Exelon had the eighth lowest CO2 emissions rate in 2011, largely due to its large nuclear and renewable energy fleet, as well as its investments in nuclear uprates. Exelon reduced its total CO2 emissions by 32 percent and its CO2 emission rate by 40 percent between 2000 and 2011, the report says.