The Public Service Commission of Wisconsin on Oct. 15 approved a May 30 request from Wisconsin Public Service Corp. for a major revamp of its gas-fired Fox Energy Center power plant.
On May 30, Wisconsin Public Service Corp. (WPSC) filed an application for a Certificate of Authority (CA) to convert the combustion technology used at its existing Fox Energy Center Units 1 and 2, located in the city of Kaukauna, Outagamie County, Wisconsin. As part of the proposed project, WPSC would enter into an amended and restated contractual service agreement with General Electric International. WPSC estimates the cost of the project to be $68,076,000, excluding Allowance for Funds Used During Construction.
The Fox Energy Center is a dual-fuel, combined-cycle electric generation facility consisting of two GE combustion turbine (CT) generators, arranged in a two-by-two-by-one configuration with two Nooter/Eriksen heat recovery steam generators (HRSG), one Toshiba condensing steam turbine generator, and associated plant equipment. Each CT-generator set includes a GE model 7FB.014 CT, a GE model 7FH2(B)5 hydrogen-cooled generator, and various subsystems. Each CT is capable of operating using either natural gas or No. 2 distillate fuel oil. Because of fuel cost, natural gas is currently used as the primary fuel, with fuel oil used as a backup fuel. Each HRSG is equipped with supplementary natural gas-fired duct burners manufactured by the Coen Co.
The nameplate capacity of the Fox Energy Center is 593 MW, with a summer rating of approximately 550 MW. During summer conditions and when operating at its design point, the net capacity of the combined-cycle facility is approximately 500 MW, with an additional 50 MW of peaking capacity available from operation of duct-firing facilities. The facility is capable of being dispatched from a load level of approximately 150 MW up to its rated capacity.
The planned project consists of the conversion, modification, and upgrade of the “hot section” of each CT from its current configuration, referred to as GE model number 7FB.0l, to an advanced technology having a design common to GE 7FA.04 and 7FA.OS models. GE 7FA series turbine models are much more common than those currently in use at the Fox Energy Center, and are better supported by GE.
The project should reduce: turbine firing temperature, pressure ratio, plant heat rate, and air emissions of several pollutants including NOX and carbon monoxide (CO), when the plant is operated above the minimum emissions compliance load. Electrical output will also increase under certain operating conditions. The enhanced design will also improve the durability of hot section components, which will reduce costs related to component repair and replacement.
WPSC proposes to construct this project during the next hot gas path inspection outage, currently scheduled during 2016 for Unit 1 and during 2017 for Unit 2.
The primary benefits of the project should include: major maintenance cost savings associated with reduced future outage durations, savings associated with reduction of maintenance costs resulting from the installation of advanced technology components, and savings associated with the more economical long-term maintenance agreement. Additional benefits include an increase in electric generating capacity, facility heat rate improvements, and mitigation of risk associated with future maintenance costs that would likely occur if the project is not pursued.
This project is consistent with that contemplated in WPSC’s October 2012 application for a certificate of authority to purchase the Fox Energy Center from another party. WPSC identified the potential benefits of the proposed project during due diligence performed in connection with its eventual acquisition of the Fox Energy Center.
Said the Oct. 15 commission order: “WPSC is granted a CA to convert the combustion technology used at its existing Fox Energy Center Units 1 and 2, and enter into an amended and restated contractual service agreement with GE, as described in its application and modified by this Final Decision, at an estimated cost of $68,076,000, excluding AFUDC, subject to conditions stated in this Final Decision.”