Boswell 3 Frequently Asked Questions

Minnesota Power’s Boswell 3 Environmental Improvement Plan addresses the Mercury Emissions Reduction Act of 2006 as well as new state and federal emission control regulations.

Is Minnesota Power’s Boswell 3 Environmental Improvement Plan (Boswell 3 Plan) required (i.e., needed now to comply with new state or federal air quality standards)?

Yes. Minnesota Power must make significant reductions in mercury, oxides of nitrogen (NOx), sulfur dioxide (SO2) and particulate matter (PM) emissions at Boswell Unit 3 to meet the requirements of the Mercury Emissions Reduction Act of 2006 and comply with other recently established and fast-approaching state and federal emission requirements.

Which coal-based generating facility is included?

The Boswell 3 Plan includes environmental retrofits at Minnesota Power’s second-largest coal-based facility. Boswell Unit 3, located in Cohasset, Minnesota, has been in service since 1973 with a gross production of 375 megawatts (MW).

What type of emission control measures are currently in place at Boswell Unit 3?

Boswell Unit 3 has a tangentially-fired boiler burning low sulfur, low mercury sub-bituminous coal. PM emissions are currently controlled by a wet particulate scrubber which also removes approximately 30 percent of boiler SO2 emissions. In addition, as operating conditions allow, Minnesota Power operates the top burner level as a combustion air port to lower NOx emissions.

What emission control technologies will be installed?

Minnesota Power will use the most mature, commercially-available technology to significantly reduce emissions of mercury. Additionally, the use of well-established control technologies, which meet Best Available Control Technology performance standards, will significantly reduce NOx, SO2 and PM.

What emission reductions will result from Minnesota Power’s Boswell 3 Plan?

Minnesota Power anticipates the following emission reductions:

NOx—81 percent

SO2—90 percent

PM—93 percent

Mercury—up to 90 percent

When does Minnesota Power plan to implement the emission control retrofits?

Minnesota Power began on-site construction in Spring 2007 with in-service planned by year-end 2009.

How much will it cost to implement Minnesota Power’s Boswell 3 Plan?

The Boswell 3 Plan has an estimated total capital cost of approximately $198.2 million and $12.5 million in annual operation and maintenance costs.

How are Minnesota Power’s Boswell 3 Plan costs recovered?

The costs of Minnesota Power’s Boswell 3 Plan are recovered through a separate line item adjustment on your monthly electric bills. 

Does Minnesota Power need approval to add the Boswell 3 Plan Adjustment onto customers’ monthly electric bills?’

Yes. The Minnesota Public Utilities Commission (MPUC) approved Minnesota Power’s cost recovery of its Boswell 3 Plan in an Order issued October 26, 2007 (Docket No. E015/M-06-1501).

Which customers see the Boswell 3 Plan Adjustment on their monthly electric bill?

The Boswell 3 Plan Adjustment is applied to the monthly electric bills of all Minnesota Power retail customers, except those customers on Minnesota Power’s Competitive Rate Schedules.

When was the Boswell 3 Plan Adjustment  first applied onto my monthly electric bill?

Minnesota Power began recovery of environmental costs on January 1, 2008.

Will I be notified of the Boswell 3 Plan Adjustment?

Yes. Minnesota Power notified customers through a bill insert prior to the first application of the Boswell 3 Plan Adjustment.

How long will the Boswell 3 Plan Adjustment continue?

The Boswell 3 Plan Adjustment will continue until all approved costs have been fully recovered or reflected in general rates.

What is my Boswell 3 Plan Adjustment?

Minnesota Power estimates that the average Boswell 3 Plan Adjustment for each rate class is:

12 Months Ended December 31, 2008

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