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Conservation group sues over pollution from Big Stone

PIERRE, S.D. -- A conservation group has filed a federal lawsuit alleging that the Big Stone Power Plant in South Dakota violated federal environmental laws by failing to install modern pollution controls in the past decade.

Sierra Club officials said the lawsuit, filed Tuesday in federal court in South Dakota, asks a judge to order Otter Tail Power Co. and other owners of the coal-fired plant to install equipment that would reduce pollution at the plant near Milbank.

The utilities should not be allowed to build a second coal-fired plant at the site when they have not cleaned up the existing plant, the conservation group said.

"What we are alleging is for the past decade beginning in 1995 this power plant has been operating illegally without modern pollution controls," said Bruce Nilles, director of the Sierra Club's National Coal Campaign.

The lawsuit alleges that federal law required Big Stone I to install modern pollution-control equipment when it made three changes to the power plant in the past decade.

The suit also seeks to make Big Stone I pay financial penalties for not installing pollution-control upgrades.

Cris Kling, director of public relations for Otter Tail and Big Stone I, said the changes were not of the type that would require the pollution-control upgrades.

"We complied with the law," Kling said.

Five utilities are seeking to build a second plant near Big Stone I, and the project would include improving pollution-control equipment in the existing plant.

They have said that Big Stone II will more than double the combined plants' generation capacity, but emissions of sulfur dioxide, nitrogen oxides and mercury from the two plants will be less than or equal to emissions from the current plant.

Big Stone II, estimated to cost $1.6 billion, also would produce less carbon dioxide than existing coal-fired plants in the region, the utilities have said.

"To my way of thinking, you get twice the power and you're going to have significant emission reductions from that site," Kling said.

The Sierra Club and other environmental organizations are also opposing the construction of Big Stone II in Milbank, which is in South Dakota near the Minnesota border, and the construction of transmission lines to carry the additional power into Minnesota.

Prevailing winds would carry most of the pollution into Minnesota, the groups have said.

Nilles said federal law requires that when an existing coal-fired plant is upgraded or modified, the plant must install modern pollution controls. Big Stone I has undergone three major changes in the past decade, but modern pollution controls have not been installed as part of those changes, he said.

The three changes were a switch to coal from Wyoming's Powder River Basin in 1995, the replacement of a heater in a boiler in 1998, and changes made to supply steam to an ethanol plant in 2001, Nilles said.

The Sierra Club in 2006 asked the U.S. Environmental Protection Agency and the South Dakota Department of Environment and Natural Resources to require the upgrades, Nilles said.

The EPA and the South Dakota officials never responded, Nilles said.

"The state and the EPA have simply been unwilling or unable to enforce clean air protections that are fundamental to making sure the air we breathe is safe and that pollution coming out of these power plants doesn't pose a public health menace," Nilles said.

Kling said changes mentioned by the Sierra Club lawsuit generally reduced pollution from Big Stone I, and utility officials believe the changes did not trigger requirements for pollution control upgrades. However, one of the projects in the lawsuit is different than one mentioned in Sierra Club's 2006 request, she said.

The switch from lignite to subituminous coal lowered sulfur emissions, a boiler change was related to the switch to the new coal, and the provision of steam to the ethanol plant did not cause any change in the power plant's boiler, Kling said.

Big Stone I is run by Fergus Falls-based Otter Tail, Montana-Dakota Utilities Resources Group Inc. and NorthWestern Energy.

The Big Stone II plant would serve about 1 million people, about half of them in western Minnesota. South Dakota officials have already approved some permits for the project.