Wisconsin Power and Light told the Wisconsin Public Service Commission on Jan. 30 that the new selective catalytic reduction (SCR) system installed on the coal-fired Edgewater Unit 5 achieved in-service status in December.
In May 2010, the commission issued an order approving the application for a Certification of Authority to install the SCR for NOx control on Unit 5 at Edgewater, located in Sheboygan County, Wisc.
The estimated cost of the approved project was $153.9m, excluding AFUDC. WP&L said the actual project costs through Dec. 31 had come in at $132.5m. As of this update, the project is forecasted to be completed within the estimated cost, it said. Construction activities on the project commenced on Aug. 2, 2010.
The SCR ductwork tie-in outage was completed in the fourth quarter of 2012. Ammonia injection was also initiated, which resulted in NOx reductions from the unit. As of the Jan. 30 update, engineering and construction progress are both 99% complete. WP&L had filed a letter on Dec. 12, 2012, updating the commission that the SCR in-service date was Dec. 5, 2012.
Among the recent project highlights:
- Completed final startup and commissioning checks on the major SCR systems in preparation for the SCR startup after completion of the SCR tie in outage.
- Performed optimization testing of the SCR system after unit restart.
- Finished post outage operations training on all new SCR and auxiliary equipment.
- Completed performance testing of the SCR on Dec. 10, 2012. Final reports will be issued from a third party testing company this quarter.
- Started 60-day guaranteed reliability test on Dec. 15, 2012.
- Continued working to address punch list and warranty items associated with the SCR installation.
New FGD installation also being pursued for Edgewater Unit 5
This is not the last emissions control project planned for Edgewater Unit 5. WP&L is now before the commission for approval of a new flue gas desulfurization (FGD installation for this new unit. Recent testimony from a commission staff official supported the FGD as a broad response to power market uncertainty.
A large amount of generation, in particular coal generation, is being removed from the electric grid in Wisconsin, with Dominion’s (NYSE: D) recent decision to shut its Kewaunee nuclear plant removing an additional 550 MW of baseload generation from the American Transmission Co. LLC footprint. In addition, Wisconsin investor-owned utilities have announced or considered over 800 MW of coal-fired generation to be retired by 2017. Nationwide, the Brattle Group is forecasting the retirement of up to 77 GW of coal-fired capacity, with up to 16 GW in the Midwest ISO footprint.
Those were among the points made Jan. 15 at the commission by Kenneth Detmer of the commission’s Gas and Energy Division. His written testimony was filed in general support of WP&L’s application to add FGD and a fabric filter on, and thus save the life of, Unit 5 at Edgewater.
“Many coal units across the U.S. and an even a greater percentage in MISO have not committed to large emission control projects because of the current economics,” Detmer wrote. “SO2 controls, such as FGD in particular, require a sizable investment and time to install. I anticipate many older units will be retired instead of retrofitted and this could lead to potential reliability issues.”
Some retirement decisions for coal units have been announced while, in other cases, the owners have neither announced retirement nor have they pursued more expensive SO2 emission controls, he added. “I refer to those units as bubble units. Some owners may attempt to operate these bubble units a few more years with limited SO2 controls such as dry sorbent injection. The installation of SO2 controls in particular may not be cost effective for many of the coal units and this may force a retirement decision.”
WP&L picked dry FGD, with Powder River Basin coal as the design fuel, for installation at Edgewater Unit 5. WP&L, a unit of Alliant Energy (NYSE: LNT), provided details about the project in its July 2012 request for authorization from the PSC.
Edgewater Unit 5 is one of WP&L’s larger and most efficient units. It consists of a wall-fired boiler with a gross maximum operating load of 430 MW. It is equipped with low NOx burners, separated overfire air and the new SCR system to reduce NOx emissions. Edgewater 5 is also equipped with a cold-side electrostatic precipitator for particulate control and activated carbon injection to reduce mercury emissions.