Wisconsin PSC staff outlines issues in Weston 3 retrofit case

As the Public Service Commission of Wisconsin moves closer to a decision on an emissions control project for the coal-fired Weston Unit 3 of Wisconsin Public Service, commission staff on March 4 filed a briefing memo that outlines the positions of the parties in the case.

The memo, which is up for comment from parties to the case until March 13, makes no recommendation on how the commission should decide.

Weston is located south of the city of Wausau in Marathon County. It includes four coal-fired units, two natural gas/oil-fired combustion turbine (CT) generators, and auxiliary systems. Weston 3 is the second largest coal-fired unit, with a capacity of 320 MW using primarily sub-bituminous Powder River Basin coal. It has been in service since 1981. Existing emissions control facilities include fabric filters installed in 2000 for better particulate control, low-NOX burners installed in 2009, and an activated carbon injection system (ACI) installed in late 2009 for mercury emissions control.

The proposed new emissions control project is a multi-pollutant control technology known as ReACT. The ReACT system would be located downstream from the existing Weston 3 baghouse. It would involve three process stages:

  • adsorption of SO2, NOX, and mercury onto a moving bed of activated coke pellets as flue gas passes through it;
  • regeneration of the activated coke pellets by thermal desorption of the pollutants; and
  • byproduct recovery, including creation of sulfuric acid.

The purpose of the ReACT proposal in this proceeding, which began in May 2012, is to reduce SO2, NOX and mercury emissions from Weston 3 to comply with current and future state and federal emissions regulations and the Consent Decree that WPSC recently entered into with the U.S. Environmental Protection Agency (EPA).

The utility estimates that the cost of construction as $275m, excluding allowance for funds used during construction (AFUDC). The AFUDC associated with the project would be $41m.

Under the terms of its Consent Decree with the EPA, air emission controls on Weston are required by the end of 2016, and the proposed ReACT project is a cost-effective solution consistent with the Consent Decree. The utility also argues that the legal risk of the Consent Decree being changed or rejected is low, but, if that does occur, any subsequent settlement is likely to include ReACT.

WPSC contends that Weston 3 is an important resource in its generation portfolio given that its Purchase Power Agreement (PPA) with Dominion (NYSE: D) for 335 MW from the Kewaunee Nuclear Power Plant expires at the end of 2013, and further, that the Consent Decree calls for retiring, re-fueling, or re-powering the coal-fired Weston Units 1-2 and Pulliam Units 5-6 by June 1, 2015.

Critics during this case have said that ReACT has not been commercially proven in the U.S., but the utility has said it has been extensively used in other countries and successfully tested in the U.S.

Also on March 4, Wisconsin Public Service filed a breakdown with the commission of expected costs to comply with the Consent Decree with EPA. It includes capital costs of $8.1m for a Pulliam Units 7 and 8 dry sorbent injection project, to be spent by April 2015, and the Weston 3 ReACT project, with $275m in capital cost by the end of 2016.

“The consent decree requires WPSC to retire, refuel, or repower Pulliam 5&6 and Weston 1&2 by June 1, 2015,” the filing said. “At this time the Company does not believe repowering any of these units will be cost effective. The decision between retire and refuel depends on capital cost, fuel supply cost and availability, and the broader MISO capacity market. A preliminary engineering study and capital cost estimate for refueling is under way. A decision will likely be made by Q4 2013.”

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.