Sierra Club demands Big Stone Power Plant cut pollution

Big Stone Power plant
The Big Stone power plant on the Minnesota-South Dakota border. The Sierra Club is filing papers to try and prevent the expansion of the plant, citing environmental concerns.
MPR Photo/Mark Steil

The coal-fired power plant is located near Big Stone City, South Dakota, just a few miles west of Ortonville, Minnesota. Sierra Club attorney Bruce Nilles says prevailing winds means Minnesota residents suffer most of the plant's pollution, including nitrogen oxide, sulfur dioxide and mercury.

Nilles says since the plant was built before the Clean Air Act took effect in the 1970s, it was not required to upgrade its equipment to meet the act's stringent requirements. He says, however, the legislation does require older plants to install new pollution equipment in certain circumstances.

Big Stone from Ortonville
The Big Stone plant as seen from Ortonville.
MPR Photo/Mark Steil

Nilles says one trigger is if a power plant undertakes a significant improvement project.

"In this case, they undertook three major projects to extend the life of this project, and increased air pollution in the process -- never installed modern pollution controls," says Nilles.

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Nilles says the three projects over the last 11 years included changes to the boilers and main turbine. He says at most, Big Stone's owners have made only modest efforts to fight pollution. He says, for example, the plant's move to a new coal source was a good move, but only half a step.

"In 1995 they switched from burning primarily lignite to a low-sulfur sub-bituminous coal. In the process of doing that they dramatically increased their emissions of particulate matter -- fine particles otherwise known as soot -- and never notified the regulatory agency, and never got a permit and never installed stringent pollution controls," says Nilles.

Nilles says state-of-the-art pollution-fighting equipment could eliminate up to 90 percent of the pollution. He says Big Stone is one of the nation's dirtiest power plants.

Control room
The control room in the Big Stone power plant.
MPR Photo/Mark Steil

Otter Tail Power Company of Fergus Falls is the plant's majority owner; NorthWestern Energy of Sioux Falls and Montana-Dakota Utilities of Bismarck also own shares.

Nilles says the Sierra Club sent the owners a letter saying it intends to sue the companies for Clean Air Act violations. Otter Tail's Cris Kling says the company has not yet received the letter.

"It's hard to respond when we haven't received the allegations or the letter that you described. But we have not received any notices of violation from any state or federal authority," says Kling. "We're confident we're in compliance with all requirements. That's how we do business."

Sierra Club attorney Bruce Nilles says he wants to talk with Big Stone officials and try to reach an agreement. He says if nothing happens in the next 60 days towards that goal, the Sierra Club will file suit in federal court in South Dakota.

Otter Tail, Montana-Dakota and five other companies plan to build a second major coal plant at the Big Stone City site. Big Stone II, as it's known, is now going through the regulatory approval process and construction could begin next year.

The Sierra Club's Bruce Nilles says the lawsuit against Big Stone I should have an impact on those plans.

"Obviously, before you go building and spending $1.8 billion on a new coal plant, you should make sure your existing operations are fully in compliance with the Clean Air Act," says Nilles. "So we hope this will help spur Otter Tail Power and the others to put their new plant on hold while they get their existing house in order."

Otter Tail Power's Cris Kling says more pollution equipment will be installed at the power plant as part of the Big Stone II project.

The Sierra Club's Nilles says his organization has about a dozen lawsuits of this type currently filed against power plants around the U.S. One was recently settled in Green Bay, Wisconsin. Under that agreement several boilers at the J.P. Pulliam plant will be upgraded and at least two will be shut down.