EPA Proposes New Limits on Mercury, Sulfur Dioxide Emissions From Power Plants

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The Environmental Protection Agency announced proposed rules March 16 that would establish new limits on emissions of mercury, acid gases, and sulfur dioxide from new and existing power plants, a move environmental groups said would provide significant protection for public health.

The proposed national emissions standards for hazardous air pollutants for power plants would establish numeric, technology-based emissions limits on mercury, toxic metals, and acid gases.

Proposed revisions to the new source performance standards for steam-generating units at power plants would set more stringent emissions limits for sulfur dioxide, nitrogen oxides, and particulate matter.

At a news briefing, EPA Administrator Lisa Jackson said the rules would require power plants to install “proven and widely available pollution technology,” such as scrubbers, baghouses, and other controls.

The proposed rules would prevent 91 percent of the mercury in coal burned at power plants from being emitted, while reducing acid gas emissions--hydrogen chloride and hydrogen fluoride--by 91 percent and sulfur dioxide by 53 percent, according to EPA.

Power plants are the largest remaining source of several toxic air pollutants and are responsible for half the mercury and more than half the acid gas emissions in the United States, EPA said. According to agency estimates, about 1,200 existing coal-fired electricity generating units and 150 oil-fired units at about 525 power plants would be affected by the proposals. While many newer power plants have already installed the required controls, EPA said 44 percent of the plants still lack advanced pollution controls.

EPA estimates the rules, which would amend 40 C.F.R. Parts 60 and 63, would yield 31,000 short-term construction jobs and 9,000 long-term utility jobs as power plants install the required controls. (See related article in this issue.)

Rule Said to Prevent 17,000 Deaths.

Jackson said the rules would prevent as many as 17,000 premature deaths and 11,000 heart attacks per year. Complying with the emissions standards would cost the utilities $10.9 billion in 2016, while providing between $59 billion and $140 billion in health benefits, the agency said.

John Walke, director of Clean Air Programs at the Natural Resources Defense Council, told BNA the health benefits of the proposed rules place them in “the top three greatest air pollution accomplishments in history.”

The hazardous air pollutant rule would replace EPA's Clean Air Mercury Rule, which the U.S. Court of Appeals for the District of Columbia Circuit struck down in 2008 (New Jersey v. EPA, 517 F. 3d 574, 65 ERC 1993 (D.C. Cir. 2008); 39 ER 301, 2/15/08).

EPA had a court deadline to propose the hazardous air pollutant rule by March 16 as part of a consent decree with public health and environmental advocates, including the American Lung Association. The final rule is due by Nov. 16. (American Nurses Ass'n v. Jackson, D.D.C., No. 08-2198, consent decree entered4/15/10; 41 ER 877, 4/23/10).

Toxics Rule Requires Mercury Controls.

The proposed national emissions standards for hazardous air pollutants for coal- and oil-fired electric utility steam generating units would set separate emissions limits for five subcategories of coal- and oil-fired power plants.

Issued under Section 112 of the Clean Air Act, the maximum achievable control technology standards represent the average of emissions controls for hazardous air pollutants being achieved by the best-performing 12 percent of power plants.

The proposed air toxics rule would set emissions limits of total particulate matter, which is used as a surrogate for toxic metals, as well as hydrogen chloride and mercury for new and existing coal-fired units designed for coal with a heat input greater than or equal to 8,300 pounds per million British thermal units (lb/MMBtu), coal-fired units designed for coal with a heat input less than 8,300 lb/MMBtu, units that burn solid oil-derived fuel, and units that burn gasified coal or solid oil to control emissions.

New and existing units that burn liquid oil fuel would be required to control emissions of toxic metals, including mercury, as well as hydrogen chloride and hydrogen fluoride.

EPA is also proposing alternative emissions limits for some pollutants. Units that have flue gas desulfurization systems, commonly known as scrubbers, can choose to meet a sulfur dioxide emissions limits as a substitute for hydrogen chloride. All units except those that burn liquid oil would be able to meet individual emissions limits for toxic metals or a total toxic-metals emissions limit rather than the particulate matter emissions limits. Additionally, liquid oil-fired plants would be able to meet individual emissions limits for toxic metals rather than meeting the total metals emissions limit.

For organic toxic emissions like dioxins and furans, EPA is proposing the power plants conduct annual performance tests to ensure the units are burning fuel efficiently.

Performance Standards Revised.

EPA also proposed more stringent pollution performance standards for new, modified, or reconstructed fossil fuel-fired electric steam generating units at power plants.

New source performance standards, issued under Section 111 of the Clean Air Act, are also technology-based standards regulating emissions of criteria pollutants such as sulfur dioxide and particulate matter. EPA revised the new source performance standards for steam generating units at power plants at 40 CFR part 60, subpart Da in 2006 (71 Fed. Reg. 9866; 37 ER 334, 2/17/06).

EPA is proposing a total particulate matter emissions limit of 7.0 nanograms per joule (ng/J)(0.055 pound per megawatt hour) of gross energy output for new and reconstructed units and 15 ng/J (0.034 lb/MMBtu) for modified units. The existing particulate matter limit is 0.015 lb/MMBtu.

For sulfur dioxide, EPA is proposing an emissions limit of 130 ng/J (1.0 lb/MWh) gross energy output for new and reconstructed steam generating units. The agency did not propose to amend the standards for modified units or those that burn more than 75 percent coal refuse. The existing standard is 1.4 lb/MWh.

EPA is proposing two options for the nitrogen oxides emissions standard. Its preferred option would set a combined standard for emissions of both nitrogen oxides and carbon monoxide of 150 ng/J for new and reconstructed units and 230 ng/J for modified units.

“EPA prefers the approach of establishing a combined standard because it provides additional compliance flexibility while still providing an equivalent or superior level of environmental protection,” it said.

The agency also proposed a standard for nitrogen oxides only of 88 ng/J (0.70 lb /MWh) gross energy output.

Comments on the proposed rules will be accepted for 60 days from the date they are published in the Federal Register.

Comments can be submitted at http://www.regulations.gov. Comment on the proposed national emissions standards for hazardous air pollutants rule should reference docket No. EPA-HQ-OAR-2009-0234, and those on the proposed new source performance standards should reference docket No. EPA-HQ-OAR-2011-0044.

EPA also plans to hold three public hearings on the proposed rules. The dates and locations will be announced separately.

By Andrew Childers

More information on EPA's proposed standards to limit mercury, acid gases, and other toxic pollution from power plants is available at http://www.epa.gov/airquality/powerplanttoxics/actions.html.

For more information on the proposed national emissions standards for hazardous air pollutants, contact William Maxwell in EPA's Office of Air Quality Planning and Standards at (919) 541-5430 or maxwell.bill@epa.gov.

For more information on the proposed new source performance standards, contact Christian Fellner in EPA's Office of Air Quality Planning and Standards at (919) 541-4003 or fellner.christian@epa.gov.