Backers move forward with one SCR at Laramie River coal plant

The Missouri Basin Municipal Power Agency d/b/a Missouri River Energy Services (MRES) said in a June 30 integrated resource plan filed with the Minnesota Public Utilities Commission that a new selective catalytic reduction (SCR) system is being installed at the Laramie River coal plant in Wyoming while a court case is fought out over further SCR installations at the plant.

Since the previous resource plan and updates were filed, there have been significant developments related to the application of the Regional Haze rules under the Clean Air Act as they apply specifically to Laramie River Station (LRS), the only coal-fired generating resource in the MRES portfolio, said the resource plan.

The Regional Haze provisions of the CAA require facilities that began construction between 1962 and 1977, which includes LRS, to identify and apply Best Available Retrofit Technology (BART) to control SO2 and NOx if their emission rates for those pollutants exceed a certain designated level. LRS has installed over-fire air technology and low-NOx burners for all three units to address these BART requirements.

In January 2014, the U.S. Environmental Protection Agency partially disapproved that portion of the Wyoming State Implementation Plan (SIP) for NOx removal, and issued its own final rule imposing a Federal Implementation Plan (FIP) with more stringent emission limits. The FIP: imposes NOx emissions limits 0.07 pounds per MMBtu (30 day rolling average); applies to all three units; and requires the installation of SCR technology, in addition to the previously installed low-NOx burners and over-fire air.

Said the IRP: “The difference in visibility improvement for the FIP’s SCRs versus the Selective Non-Catalytic Reduction (SNCR) technology called for in the SIP adopted by Wyoming is less than one deciview (a deciview is the lowest measurable increment perceptible by the human eye). However, the cost difference to install three SCRs as opposed to three SNCRs is greater than $500 million for the entire project. Under the FIP, the owners of LRS3 are required to install SCR equipment on LRS Units 1, 2 and 3 by March 4, 2019.”

It said that Basin Electric Power Cooperative, as Operating Agent of LRS and on behalf of all the owners, appealed this decision to the U.S. Court of Appeals for the Tenth Circuit. The state of Wyoming, PacifiCorp and Powder River Basin Resource Council also appealed the FIP. In September 2014, the Tenth Circuit granted a stay of enforcement pending appeal, extending the deadline for compliance with the FIP for the duration of the stay for LRS (and other utility units that are the subject of the appeal).

The IRP noted: “The appeal is ongoing, and oral arguments are expected to occur later this year. It is unknown when the Tenth Circuit will consider the cases, or the ultimate outcome when a decision is finally issued.”

The estimated cost to the Western Minnesota Municipal Power Agency, an MRES member, for its share of the expense of installing SCRs on all three units is $125 million, compared to $17 million for the alternative SNCRs that were required by Wyoming’s SIP.

The Missouri Basin Power Project (MBPP) consists of Laramie River Station and associated facilities, and is owned by six consumer-owned electric utilities. The MBPP participants include Western Minnesota, which owns a 16.47% share of MBPP (as tenants in common). Western Minnesota sells its entitlement to capacity, energy, and transmission and MRES purchases all of its resources pursuant to an exclusive contract between the parties.

The MBPP is actively evaluating SCR technology necessary for compliance with the final rule, and is moving forward to install SCR technology on Unit 1, the IRP said. “The installation of a single SCR requires not only a major capital investment, but it also imposes a significant parasitic load that will reduce the net output of the unit, and require that the unit is taken out of service for a substantial period of time,” the IRP added.

For the purposes of the IRP, to provide a basis for developing scenario models, it was assumed that each of the three units at LRS is required to install SCR. This is based on the existing EPA FIP for Wyoming, including the provisions related specifically to LRS, and assumes that these regulations will survive the current legal challenge pending before the Tenth Circuit.

LRS is a coal-fired plant consisting of three units, located near Wheatland, Wyoming. MRES receives energy from Unit 1. The other two units are currently connected to the western US electrical interconnection and are not physically capable of delivery to MRES. MRES receives 281 MW in 2016 and every third year thereafter; in all other years it receives 282 MW. The LRS units are: Unit 1, 570 MW (net), began operating in 1980; Unit 2, 570 MW (net), began operating in 1981; Unit 3, 570 MW (net), began operating in 1982.

Basin Electric had announced in January that its board of directors approved the installation of this Laramie River SCR. Jim Lund, Basin Electric senior project manager, said at the time that construction wiould begin in 2017, with the equipment operating by mid 2019. The project is estimated to cost about $330 million. The project work will be completed and installed during two major outages, one at the beginning of the project and one at the end.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.