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Reducing Emissions

Minnesota Power continually monitors how each of our generating units fit with our long-term energy strategy to balance environmental impact, reliability and cost.

We’re preparing for a major clean air project at Boswell Energy Center in Cohasset, Minn. Boswell Unit 4 is our largest generator and the workhorse of Minnesota Power’s generation fleet. The $350 million project will take several years to complete.

Since 2005, we’ve invested more than $350 million at our coal-fired power plants to reduce emissions and improve efficiency. Much of this investment applied to Boswell Unit 3, the company’s second largest generator. The technology upgrades at Boswell, Laskin Energy Center and Taconite Harbor Energy Center have resulted in a 70 percent reduction of overall air emissions—including mercury, nitrogen oxide, sulfur dioxide and particulates—across the Minnesota Power generation fleet.

The technology solutions that Minnesota Power uses vary by plant to get the most reduction in emissions for the least cost to customers and to be compliant with federal and state regulations. Here are some highlights of what we’ve accomplished so far:

  • Boswell Energy Center Unit 3 has been removing more than 90 percent of its mercury air emissions since 2009 when a massive emissions control project was completed.
  • Two units at Boswell and one unit at Taconite Harbor Energy Center are removing mercury at rates ranging from 60–80 percent. Two units at Taconite Harbor are expected to be at about a 90 percent removal rate by the end of 2012.
  • Mercury air emissions across the generation fleet have been reduced by 39 percent since 2005. By 2016 it’s expected that mercury emissions will be reduced by 86 percent.
  • Minnesota Power’s overall air emissions, including mercury, nitrogen oxide, sulfur dioxide and particulates, have dropped about 70 percent since 2005.
  • Mercury water emissions at Boswell have been reduced by more than 50 percent. Mercury water emissions have been nearly eliminated at Laskin and Taconite Harbor.
  • Minnesota Power is optimizing the use of biomass (wood waste) and reducing dependence on coal at the Hibbard Renewable and Rapids Energy Centers. Mercury concentrations in biomass are lower than in coal.
Mercury air emissions across Minnesota Power’s generation fleet have been reduced by about 39 percent since 2005. Much of that is related to a huge emissions control project at Boswell 3.

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