After a verbal approval earlier in the month, the Public Service Commission of Wisconsin on Jan. 30 issued a final written order approving a $150m selective catalytic reduction project on the coal-fired Columbia Unit 2.
In July 2014, Wisconsin Power and Light (WP&L), Wisconsin Public Service Corp. (WPSC), and Madison Gas and Electric Co. (MGE) sought approval for this project. The applicants propose to construct the facilities to reduce NOX air emissions and to comply with the NOX emissions requirements included in a Consent Decree submitted to the U.S. District Court for the Western District of Wisconsin in April 2013. The estimated cost of the project is $150m, excluding Allowance for Funds Used During Construction (AFUDC).
The Columbia Energy Center is located south of Portage, Wisconsin, along the Wisconsin River. The facility consists of two coal-fired units, designated as Units 1 and 2. These units began operation in 1975 and 1978, and have nameplate generation capacities of 512 MW and 511 MW, respectively. The applicants jointly own both units, with WP&L holding a 46.2% share, WPSC holding a 31.8% share, and MGE owning the remaining 22%. WP&L operates both units. Both units currently utilize sub-bituminous Powder River Basin coal obtained from various mines.
The technology proposed for NOX reduction at Columbia Unit 2 is a conventional SCR system. This technology removes NOX from the flue gas via a catalyzed reaction with an ammonia-based reagent. The preliminary design for the SCR consists of these major components: one reactor with multiple layers of catalyst; an ammonia storage and delivery system; an ammonia injection system; steam soot blowers or sonic horns, or both; instrumentation; and ductwork modifications.
“The impact of the U.S. Environmental Protection Agency’s (EPA) proposed Clean Power Plan (CPP), also referred to as 111(d), on the proposed project was also considered by the applicants,” the commission noted. “At this time, it is too early to understand the exact impacts of the CPP. The EPA is expected to publish the final CPP in June 2015, after which the state would be required to submit its State Implementation Plan to EPA by June 2016. The applicants anticipate that newer, larger, and more-efficient units, such as those at Columbia, will remain an important part of the generation fleet.”
The applicants intend to award a limited contract to start engineering for the SCR system during the first quarter of 2015 and a final notice to proceed during the third quarter of 2015. Site mobilization is anticipated to begin in the second quarter of 2016, with the project anticipated to be placed in service during the third quarter of 2018.