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Big Stone II Coal Plant Proposal - Background


photo: Big Stone Power Plant

Big Stone Coal is a coal plant located near Milbank, South Dakota, roughly four miles from Ortonville, Minnesota. It is a 450 MW coal plant built in 1975. The plant burns coal and tire-derived fuel (TDF) as part of a tire-pile reduction project in South Dakota. In 2003 it burned 1.3 million tires. It is of interest to us now because the site is the proposed location for Big Stone II, a 600 MW coal plant proposed to come on-line in 2011 that will begin permitting processes this year.

The need for a new coal-fired energy-generating facility is based upon projections for energy demand in the next decade or so. Big Stone states that it expects energy demand to grow by 15-25% by 2012. They chose Big Stone as the location because when it was built infrastructure was put in place for a second unit, and to take advantage of this brown field.

The majority owner of Big Stone is Otter Tail Power Company. Otter Tail's website indicates that coal (Powder River Basin) and biomass are being considered as fuels, and that best available control technologies (based on state and federal regulations) will be used. An NPR article from February 16th of this year states that coal gasification is planned for the plant. Big Stone stated it expected emissions 90% lower than their existing coal generation facility by using gasification. However, Otter Tail's website states that coal gasification was considered and ruled out as not commercially viable. I called Otter Tail to ask if gasification has been ruled out, but the appropriate persons could not be reached. I will be following up with appropriate persons as instructed by Otter Tail to determine whether or not coal gasification has been ruled out.

The plant is expected to last 40 years and cost about $1 billion, including administration and engineering but not including transmission costs. The plant will employ 30-40 people once the plant is built. Construction is expected to take four years and employ an average of 625 workers, with a peak of 1,500 workers. Most of the transmission for the plant will be in Minnesota. They expect to spend $60-$100 million on transmission, which will mostly be borne by the customers of the plant. The cost of energy from the plant is expected to be $1,666 per MW. They say that this seems high and go on to note the environmental controls and regulations applicable to the plant. They will be seeking tax breaks from South Dakota.

The timeline for the plant is as follows: Announcement in 2004, permitting and public comment from 2005-2006, construction commenced in 2006, commercial availability in 2011. In 2005 the company will begin applying for the following forms or permits, authorization, and review:

  1. From the federal government:
    1. A federal EIS.
  2. From South Dakota:
    1. Plant site;
    2. Air permit;
    3. Water appropriations;
    4. Ash disposal; and
    5. Possible transmission route permit.
  3. From Minnesota:
    1. IRP approval;
    2. Certificate of Need for the transmission line; and
    3. Transmission line route permit.

Otter Tail expects that an EIS will be required for the plant. Air emissions information on Otter Tail's website is very general. Otter Tail's site indicates they intend to use highly effective control technology and expect emissions as follows: less PM10 than other coal plants, sulfur dioxide emissions at 10% of other coal plants, nitrous oxide emissions at 5% of other plants, and fewer carbon dioxide emissions than other plants based upon the planned pulverized coal super critical boiler. They tentatively plan on using activated carbon injection for mercury control, but are willing to consider other more cost-effective technologies.

Big Stone is currently owned by Otter Tail Power (the majority owner), Northwestern Energy, and Montana-Dakota Utilities. The Big Stone II proposal has been funded so far by eight utilities: Otter Tail Power (lead developer), Central Minnesota Municipal Power Agency, Great River Energy, Heartland Consumers Power District, Hutchinson Utilities Commission, Missouri River Energy Services, MDU Resources Group, and Southern Minnesota Municipal Power Agency. Currently these entities have funded studies related to the proposal. Their participation in the project will be determined once the studies are complete. The subjects of the studies are estimates of air emissions rates, cost performance comparison of coal combustion and emissions technologies, and transmission capability studies.

Finally, here a few interesting notes about the existing coal plant:

  1. Big Stone intends to build rail service crossing into Minnesota. A Minnesota consultant service noted that there are wetland impacts associated with this, which of course means a 404 permit from the Army Corps of Engineers and 401 certification (potentially) from MPCA or South Dakota. This could be another area of public comment, although the consultant noted they recommended, and the proposer adopted, an alternative plan that would reduce wetland impacts.
  2. Big Stone will be the first plant to install a new particulate control device expected to reduce PM emissions to .0007 lbs per million Btu, less than current federal standards for PM. The article didn't state what impact it would have on PM2.5 versus PM10. The device is an Advanced Hybrid Particulate Collector, using a baghouse, fabric filter, and electrostatic precipitators. The action is being taken pursuant to an agreement with the DOE, and with $6.5 million from the DOE.