The coal-fired Unit 2 of Duke Energy Indiana‘s Cayuga coal plant, down since October 2014 due to an unexpected problem, is due back in operation by the end of May.
John D. Swez, employed by fellow Duke Energy (NYSE: DUK) subsidiary Duke Energy Carolinas LLC as Director, Generation Dispatch and Operations, supplied April 30 fuel cost testimony to the Indiana Utility Regulatory Commission on behalf of Duke Energy Indiana.
He wrote that Cayuga Unit 2 entered a forced outage on Oct. 22, 2014, following a failure in the Intermediate Pressure (IP) section of the turbine. The failure required replacement of several blade rows in the High Pressure (HP) and IP sections of the turbine. In order to minimize the overall outage time for the unit, the company moved the previously scheduled spring selective catalytic reduction (SCR) tie-in outage that was scheduled for March 21, 2015, until May 31, 2015. The planned outage work is being completed in the current outage, as is the repair to the turbine. The unit is scheduled to be back on-line by the end of May, Swez added.
Multiple rotating and stationary blade rows in the HP and IP sections of the turbine were damaged during the event and required replacement. The repairs were completed and the HP/IP turbine was re-installed in the unit on April 3. During the course of the repair of the HP/IP turbine, inspections were also performed on the unit’s two Low Pressure (LP) turbines (LP A and LP B). Damage unrelated to the incident was found on rotating blades of one of the LP turbines. Upon review of the condition of this row of blades the decision was made to perform a replacement of this blade row on both the LP A and LP B turbines which impacted the schedule for returning the unit to service.
The 1,104-MW Cayuga Station is a three-unit facility built between 1970 and 1993.
Swez also noted that the coal-fired Wabash River units 2-5 will be retired by April 15, 2016. These units were granted a one-year extension of the April 2015 federal Mercury and Air Toxics Standards (MATS) compliance date due to the need for at least two of the four units to operate at any given time for transmission system reliability (in addition to Wabash River unit 6, which also has a one-year MATS rule extension of time).
In consideration of the minimization of MATS-related emissions during the extension period and the operational complexities of units at this point in the lifecycle, Duke Energy Indiana is employing a Midcontinent ISO offer strategy which prioritizes availability and operation of the units to solve transmission reliability constraints. As a result, Duke Energy Indiana will generally be holding two of the four of Wabash River units 2-5 in reserve shutdown available for emergency operation only. The number of units in reserve versus operation may vary depending on unit availability, the needs of the transmission system, and energy prices in the MISO market. Given that the units are nearing the end of their useful lives, the company’s goal will be to maintain the availability of the generating units primarily for transmission reliability support, and specifically to maintain availability during peak demand times such as summer and winter periods when transmission-related events and/or energy prices could have the highest customer impact. Because these units will not be available for the full MISO capacity planning year, Duke Energy Indiana sought and was granted a Federal Energy Regulatory Commission waiver so that it was not required to offer the units into the MISO resource adequacy capacity market for planning year 2015/2016.
The 668-MW Wabash River plant is a six-unit station that was completed between 1953 and 1968. It is the site of the 260-MW Wabash River Coal Gasification Repowering Project (which replaced the old Unit 1 in the 1990s), which is owned by the Wabash Valley Power Association.