Luminant switches a second unit at the Martin Lake coal plant into seasonal operations

There are four coal units with 2,630 MW in total that are now in seasonal operation

Energy Future Holdings has taken one 750-MW coal unit at its Martin Lake power plant off of regular, year-round duty, and pushed it over into the seasonal operations category.

Buried in a July 23 disclosure statement that Energy Future Holdings, which controls power generating companies in Texas under companies collectively referred to as "Luminant," filed with its bankruptcy court is a section describing the company's coal-fired capacity. There are changes made in this version from an initial disclosure statement filed with the court this past April 14.

Under the category for "Year-round or full operations" in the April version, there was mentioned 11,892 MW of coal, nuclear and gas-fired capacity at 33 units. Then in the July 23 version, that falls to 11,142 MW at 32 units. That means one less unit in that category at 750 MW.

Then under "Seasonal operations" for coal/lignite units only, the April version has 1,880 MW in total at three units, then the July 23 version shows 2,630 MW at four units. That means 750 MW and one unit has been added in that category. The seasonal designation means the affected units operate only during high-demand periods (e.g., during the peak demand of summer).

Luminant’s lignite/coal-fueled generation operations include twelve units at five plant sites, with total nameplate capacity of 8,017 MW. These include:

  • two units at Big Brown with total nameplate capacity of 1,150 MW;
  • three units at Monticello with total nameplate capacity of 1,880 MW;
  • three units at Martin Lake with total nameplate capacity of 2,250 MW;
  • two units at Oak Grove with total nameplate capacity of 1,600 MW; and
  • two units at Sandow with total nameplate capacity of 1,137 MW.

Luminant’s lignite/coal units are generally available for full operations throughout the year except when they are out of service for either a scheduled or unscheduled maintenance outage. In recent years, Luminant has reduced electricity generation from selected lignite/coal units during times when the demand for electricity and wholesale electricity prices in the Electric Reliability Council of Texas (ERCOT) market are comparatively low. These reductions are achieved through short-term reductions of operations in response to low wholesale electricity prices or longer-term seasonal shutdowns in response to sustained periods of relatively low wholesale electricity prices and demand for electricity.

Two units at Monticello and two units at Martin Lake are currently subject to seasonal operations, said the July 23 filing. In the April version, there was only one unit at Martin Lake in the seasonal category.

Luminant’s lignite/coal-fueled units operated at 69.6%, 74.1%, and 70.0% of nameplate generation capacity for the years 2014, 2013, and 2012, respectively. In 2011 and 2010, the units performed at the top decile for U.S. coal-fueled generation facilities. Reduced generation in 2012 through 2014 was largely due to low wholesale electricity prices in the ERCOT market. Coal/lignite-fueled generation accounted for 58% of Luminant’s nameplate capacity and 72% of Luminant’s electricity generation in 2014.

In 2014, Luminant mined approximately 30 million tons of lignite to fuel its generation plants, and approximately 56% of the fuel used at the Big Brown, Monticello and Martin Lake facilities and 73% of the fuel used at all of Luminant’s lignite/coal fueled facilities was supplied from surface-minable lignite reserves located adjacent to Luminant’s plants. The rest of the coal for the plants is basically Powder River Basin coal railed in to the plants.

Barry Cassell
About the Author

Barry Cassell

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 26 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.

Barry can be reached at barryc@pennwell.com.