The Minnesota Pollution Control Agency is taking comment until May 2 on a draft air permit renewal for Minnesota Power‘s Taconite Harbor Energy Center that in part covers the shutdown last year of the coal-fired Unit 3 at the plant.
Taconite Harbor is a steam electric plant consisting of three identical tangentially-fired coal-burning units located in Schroeder, Cook County, Minnesota, on the north shore of Lake Superior. Boilers 1 and 2 are permitted to burn bituminous and sub-bituminous coal, as well as distillate fuel oil (which is used primarily for startup). Boiler 3 was shut down as of June 1, 2015, and is not permitted to operate.
Each unit is capable of a heat input of 900 mmBtu/hr, with net generating capacities of 79 MW (Boiler 1) and 76 MW (Boiler 2). Currently the facility uses western subbituminous coal which is received by boat and stored in an outdoor storage pile. Natural gas is not available at the site at this time.
The facility also includes a taconite ore loading dock that is owned and operated by the co-permittee, Cliffs-Erie LLC. The facility was formerly owned and operated by LTV Steel Mining. When owned and operated by LTV, the boilers generated electricity mostly for use by the LTV Hoyt Lakes taconite processing facility, with the remainder sold to the electric grid.
This pending permit action is the reissuance of the Part 70 Operating Permit. This permit action also incorporates requirements from a 2014 consent decree that Minnesota Power worked out with the U.S. EPA, as well as requirements of the federal Mercury and Air Toxics Standards (MATS).
The consent decree:
- reduces allowable PM, SO2, and NOX emissions;
- requires refueling, retirement, or repowering of Unit 3 no later than Dec. 31, 2015; and
- contains various other requirements related to SO2 and NOX allowances, monitoring (including submittal of a Compliance Assurance Monitoring Plan for PM emissions), stack testing, control equipment operation, and netting credits.
Also, EPA has indicated (through oral communication on Feb. 23, 2016) that if the permittee meets requirements for filterable PM testing every other calendar year (instead of every calendar year), then the permittee may test condensable PM emissions every other calendar year.
Minnesota Power requested and received a one‐and‐one‐half month extension to the MATS rule initial deadline of April 16, 2015, for Unit 3 under the premise that Unit 3 would be shutdown no later than June 1, 2015, prior to the date required by the consent decree. The draft permit memorializes that shutdown by prohibiting future operation of Unit 3.
This permit action also includes a major amendment to allow test burns of alternative fuels in Boilers 1 and 2. In addition, this permit action removes a permit requirement to submit a major amendment application for adding a boiler 2 mercury emission limit and/or control efficiency and mercury control equipment monitoring parameters and ranges, because the application was submitted in June 2013. However the June 2013 submittal was closed without action because the required mercury and/or control equipment monitoring parameters are no longer warranted because the permit contains the applicable mercury limit and continuous emissions monitoring requirements.
In its Feb. 22 annual Form 10-K report, Minnesota Power parent Allete Inc. (NYSE: ALE) mentions that Taconite Harbor Unit 3 was retired in May 2015. It added: “Future plans for Taconite Harbor are included in Minnesota Power’s EnergyForward plan which includes the economic idling of Taconite Harbor Units 1 and 2 in the fall of 2016 and the ceasing of coal-fired operations at Taconite Harbor in 2020.”