Photograph by Daniel Acker, Bloomberg/Getty
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Executives say Great River Energy’s Coal Creek Station power plant in North Dakota, among the country’s top mercury polluters in 2013, cut its mercury emissions almost 40 percent in response to an EPA rule criticized by the U.S. Supreme Court on Monday.

Photograph by Daniel Acker, Bloomberg/Getty

Which Power Plants Emitted the Most Mercury?

The Supreme Court ruled against an EPA regulation limiting mercury from power plants. Top emitters in 2013 were in Texas, Missouri, and North Dakota.

The U.S. Supreme Court on Monday dealt a blow to an Obama administration regulation cutting mercury and other toxic emissions from power plants. The court ruled that the Environmental Protection Agency didn’t do enough to consider the costs of complying. As a result, the EPA will have to reexamine and perhaps alter its rules.

But since the regulation went into effect earlier this year, many power plants have already installed equipment reducing mercury, a neurotoxin linked to lower IQs and other health effects in children, as well as other toxic substances. “Investments have been made and most plants are already well on their way to compliance,” according to an EPA statement.

Based on 2013 EPA data, here is the list of the five U.S. power plants emitting the largest volumes of mercury and mercury compounds. The list was compiled by Eric Schaeffer, who heads the watchdog group Environmental Integrity Project.

Martin Lake Power Plant - 1,381 pounds: The plant in Rusk County, Texas, is one of four owned by Texas-based energy-generation company Luminant that were among the top 10 mercury polluters in 2013.

Asked how the company is responding to the new EPA rules, spokeswoman Meranda Cohn pointed to a recent Luminant filing with the Security and Exchange Commission. It says the company, which owns several generating facilities, has spent $700 million on environment-related improvements since 2010 and will spend another $500 million in the next five years, in part to deal with EPA’s new mercury rule.

Big Brown Power Plant - 1,095 pounds: This facility is the second Luminant plant on the list and is located southeast of Dallas in Freestone County, Texas.

Labadie Energy Center - 823 pounds: The power plant in Franklin County, Missouri, owned by Ameren Missouri announced late last year that it had begun installing new equipment at a cost of $185 million. The company expects to meet federal standards by 2016.

W.A. Parish Electric Generating Station - 782 pounds: This energy facility outside Houston in Fort Bend County, Texas, is owned by energy company NRG. Company executives say it has recently installed pollution-control equipment to comply with the new rules.

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NRG Energy’s W.A. Parish Electric Generating Station is one of seven power plants in Texas among the top 10 mercury polluters in 2013, the last year data was available. The company since has installed more emissions-control equipment.

Spokesman David Knox points out that EPA tracks pollution data in pounds – not as a ratio of emissions to electricity generated. “Consequently, a very large, fully scrubbed plant (such as Parish) may have a larger number than a much smaller plant with less emission controls,” he says.

Coal Creek Station - 735 pounds: North Dakota’s largest coal-fired power plant is located 50 miles north of Bismarck and is owned by Minnesota-based Great River Energy.

Great River spokesman Lyndon Anderson says the plant already has reduced mercury emissions 40 percent. The facility now uses residual “waste heat” from the plant as well as other technologies to help remove moisture and impurities from coal before it is burned.

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