Coal-fired power plants have continued to cut their soot- and smog-forming emissions this year, according to newly released estimates from U.S. EPA.
Preliminary emissions data for the first two quarters of 2010 show declines in total emissions as well as emissions intensity -- the amount of pollution produced per unit of electricity. While some of the overall reductions reflect a 3 percent decrease in the amount of coal being burned at power plants, the intensity figures demonstrate that some of the dirtiest plants are still being retired and that the other plants continue to add emissions controls.
The roughly 850 coal-fired power plants regulated under EPA's existing Acid Rain Program emitted 2.5 million tons of sulfur dioxide during the first two quarters of this year, a 36 percent decrease from the 3.9 million tons they released during the first two quarters of 2008. Emissions of nitrogen oxides fell from 1.5 million tons to 930,000 tons, a 37 percent decrease.
Through Aug. 5 of this year, the coal plants produced 0.3 pounds of SO2 and 0.11 pounds of NOx for every million British thermal units of energy produced -- decreases of 34 percent and 35 percent, respectively.
Coal-fired power plants are the target of EPA's newly proposed Clean Air Transport Rule, which would require additional reductions in Eastern states to address pollution that crosses state lines.
By 2014, EPA aims to reduce SO2 emissions from power plants by 71 percent from 2005 levels. The agency also seeks a 52 percent reduction in NOx emissions, though that cap would need to be tightened further if the agency finalizes a tougher ozone standard.
Upon releasing the data, EPA said the new figures should ease worries about possible increases in SO2 emissions while the agency prepares to replace the Clean Air Interstate Rule. The George W. Bush-era program was rejected in 2008 when a federal appeals court ruled that EPA exceeded its authority to run interstate emissions trading programs.
In crafting the transport rule, EPA decided it lacked the authority to carry over SO2 allowances from the Acid Rain Program, EPA air chief Gina McCarthy said last month (E&ENews PM, July 6).
As a result, SO2 prices have continued to fall, leading traders and some utilities to ask Congress to intervene. Without an incentive to hold on to banked allowances, they say, power plants will not install new controls and might even choose to release pollution rather than turn on existing scrubbers.
"The market has said, 'We get the message, these allowances are worthless,'" said Thaddeus Huetteman, chairman of the Environmental Markets Association (Greenwire, July 2).
Just one power plant significantly increased its overall emissions of NOx during the first two quarters of this year, but more than two dozen coal plants significantly increased their overall SO2 emissions, according to emissions maps released by EPA.
Fifteen plants increased their SO2 emissions intensity by more than 85 percent, suggesting major changes in emissions controls.
"EPA is tracking SO2 emissions closely each quarter to evaluate further progress and assess whether backsliding may be occurring and, if so, where it may be taking place," an EPA summary of the data says. "While a few facilities are emitting more SO2 or emitting SO2 at a greater rate in 2010 than in 2008, overall emissions are still declining."
Between 1990 and 2009, total SO2 emissions fell from 15.7 million tons to 5.7 million tons. Emissions of NOx fell from 6.7 million tons to 2 million tons over the same time period.
Click here to view the plant-by-plant emissions figures.
Click here to view a nationwide map of emissions changes.