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Sierra Club hits Minnesota Power on air violations

DULUTH — The Sierra Club on Monday called out Minnesota Power for allowing 12,774 violations of Clean Air Act regulations at three of its northern Minnesota coal-fired power plants over the past five years.

Most of the violations, more than 10,000, were for opacity limits — the measurement of light passing through a smoke plume. Regulators use opacity as one indicator for how much soot or particulate matter might be leaving a smokestack.

The violations, self-reported by the Duluth-based utility, occurred at the Clay Boswell plant in Cohasset, the Taconite Harbor plant on the North Shore and the Syl Laskin plant in Hoyt Lakes.

The group said soot from coal-burning power plants can contribute to lung and heart disease and worsens asthma problems.

But Amy Rutledge, Minnesota Power spokeswoman, said the Sierra Club was “oversimplifying” what spurs opacity. Excess moisture in the air, and very low temperatures, also can cause poor opacity readings without any excess soot or health impact, she said.

“Opacity is not a pollutant. It’s a condition. In and of itself, it’s not any risk to health,’’ Rutledge said, adding that the utility measures opacity every 10 seconds at smokestacks using infrared light. The 10,000 variances “were 0.28 percent of the more than 3.5 million measurements taken over that five-year period. That means we were in compliance more than 99.5 percent of the time.”

Other violations involved reporting requirements related to the operation of its pollution-control equipment, including mercury controls, since 2009.

Michelle Rosier of the Sierra Club in Minnesota said the organization gave Minnesota Power notice last July that it would file suit in federal court to stop the violations if the utility didn’t develop a plan to solve the problems.

“It’s been over six months since we gave them notice, and they haven’t offered a viable plan, the violations continue to add up and we’re going into summer when the air quality is at greatest risk,’’ Rosier said Monday.

The Sierra Club has updated its intent to file additional violations from 2012 that just became available to the public.

“We’ll be filing the complaint sometime in the next few months,” said Casey Roberts, an attorney with the Sierra Club. “This is the most egregious number of violations for opacity that we’ve seen nationally.”

This is the first such action the Sierra Club has taken in Minnesota, although similar campaigns have occurred in other states in the group’s ongoing push to move production away from coal.

Pressed by environmental interests and the state Public Utilities Commission, Minnesota Power has been developing a new blueprint for its electrical generation needs, moving to gradually wean itself away from coal to more wind, natural gas and hydroelectric power.

Minnesota Power just a decade ago generated as much as 95 percent of its electricity from coal. That number is down to about 74 percent today. The utility hopes to move to a mix of about one-third renewables, one-third natural gas and one-third coal within the next decade.

The PUC in September approved the utility’s plan to add an additional 200 megawatts of wind energy from the Bison 4 project near New Salem, N.D.; delivery of 250 megawatts of hydropower under contract from Manitoba Hydro by 2020, with Minnesota Power planning to deliver this energy on its proposed 500-kilovolt Great Northern Transmission Line; reduction of coal-fired generation on its fleet by 185 megawatts through the conversion of Laskin Energy Center in Hoyt Lakes to a natural gas peaking station and the retirement of one of three units at Taconite Harbor Energy Center; expansion of the utility’s Power of One conservation program to meet or exceed state conservation goals of 1.5 percent.

The PUC last year also approved a $350 million upgrade to the Clay Boswell Unit 4 to add pollution-control equipment to reduce mercury emissions by as much as 90 percent.

“That effort also is going to reduce the opacity issues’’ as the utility goes from a wet to dry pollutant-removal technology, Rutledge noted.

But environmental groups note that the upgrade will do nothing to curb the plant’s carbon dioxide emissions, the primary greenhouse gas emitted through human activity, which the Environmental Protection Agency blames for climate change. Several environmental groups had opposed the Boswell 4 upgrades, saying the old coal burner should be retired and the money instead spent on additional wind, solar and other renewable energy sources.

Minnesota Power argues that those options won’t work for its “base load” demand and that the cheap, constant supply of power from the coal-fired unit is exactly what’s needed to electrify the region’s energy-gobbling taconite and paper plants that can’t wait for sunshine or wind to operate.