Short of Clean Power Plan compliance, Tri-State to retire little coal-fired capacity

Tri-State Generation and Transmission Association said in an Integrated Resource Plan/Electric Resource Plan filed Oct. 30 with the Colorado Public Utilities Commission that it plans to zero out its share of a unit at the coal-fired San Juan power plant at the end of 2017.

Tri-State said it has elected to utilize a 20-year planning period and a six-year resource acquisition period under this plan. The period covered by this plan is 2016 through 2035. The plan evaluates both supply-side and demand-side resources on an integrated basis.

The forecast in the “Base Case” or median forecast for Tri-State load growth calls for the retirement of the Tri-State share of the San Juan Generating Station by the end of 2017, and the addition of new renewable generation that is under contract, but not yet constructed. This assumes that all existing purchase and sales contracts expire on their terms (except for the Western Area Power Administration purchases which are assumed to extend through the 20-year planning horizon. That San Juan Unit 3 will be retired by Dec. 31, 2017, resulting in a loss of 40 MW of capacity.

Under a regional haze compliance plan, San Juan Units 2 and 3 would be retired by the end of 2017. The San Juan Generating Station is a four-unit coal facility with a net capacity of about 1,685 MW located in San Juan County, near Farmington, New Mexico. It is co-owned by several other parties, including Public Service Co. of New Mexico and Tucson Electric Power.

As Tri-State adds additional solar and wind resources to its generation portfolio, it said it continues to engage balancing authority operators to develop arrangements whereby Tri-State can utilize its generating assets to provide real-time balancing capabilities. For example, Tri-State and Western have an arrangement in place that allows Western the ability to re-dispatch Tri-State generating facilities to support balancing authorities’ needs.

In 2014, Tri-State’s total sales to its members was 18,699 GWh. Of this total, 10,970 GWh was generated by coal, 4,397 GWh was generated by renewables including federal hydro, 1,797 GWh was generated by Basin Electric Power Cooperative, 1,159 GWh was from market purchases, 374 GWh was generated by natural gas and 2 GWh was generated by oil.

Looking at the cooperative’s plans by power plant:

  • The Missouri Basin Power Project (MBPP) facilities consist of three coal-fired units (the Laramie River Station) near Wheatland, Wyoming. Following Unit 2 and 3 turbine rebuilds in 2012-2013, the project currently has a net capacity output of 1,710 MW, with Unit 1 rated at 570 MW, Unit 2 rated at 570 MW, and Unit 3 rated at 570 MW. The projected net heat rate is 10,350 Btu/kWh, with a capacity factor of 90% and availability factor of 90%; this is assumed to degrade by 5% between 2020 and 2029. Tri-State owns 24.13% (413 MW) of the project, with the remaining 75.87% (1,297 MW) split among five other participants. Unit 1 is dedicated to the East Side electrical grid and Units 2 and 3 are dedicated to the West Side grid. For scheduling purposes, Tri-State is allocated 206 MW from LRS 2 and 207 MW from LRS 3.
  • Craig Station Unit 1 and Unit 2. The Yampa Project facilities consist of two coal-fired units near Craig, Colorado. The project has a net capacity output of 856 MW, with each unit rated at 428 MW. Craig Unit 1’s projected net heat rate is 10,100 Btu/kWh, with a capacity factor of 83% and availability of 92%; this is assumed to degrade by 5% between 2020 and 2029. Craig Unit 2’s projected net heat rate is 10,100 Btu/kWh, with a capacity factor of 83% and availability of 92%. To meet a regional haze NOx requirement, a Selective Catalytic Reduction (SCR) system will be installed on Craig Unit 2 by the compliance deadline. Tri-State owns 24% (206 MW) of the project, with the remaining 76% (650 MW) split among four other participants.
  • Craig Station Unit 3 is a coal-fired unit that is co-located with the Yampa Project. The unit has a net capacity of 448 MW. Its projected net heat rate is 10,050 Btu/kWh, with a capacity factor of 83% and availability of 94%; this is assumed to degrade by 5% between 2020 and 2029. To meet a regional haze NOx requirement, Selective Non-Catalytic Reduction (SNCR) will be installed on Craig Unit 3 by the compliance deadline.
  • San Juan is a coal-fired station consisting of four units located near Farmington, New Mexico. Tri-State owns 8.2% or 40 MW of San Juan 3, which is rated at 500 MW. Tri-State has announced it will retire its 40 MW no later than Dec. 31, 2017. Until 2017, its projected net heat rate is 11,600 Btu/kWh, with a capacity factor of 85% and equivalent availability of 70%.
  • The Escalante station is a coal-fired facility located near Grants, New Mexico. The station is rated at 245 MW. Its projected net heat rate is 10,300 Btu/kWh with a capacity factor of 77% and availability of 93%; this is assumed to degrade by 5% between 2020 and 2029.
  • The Nucla generating facility is a coal-fired unit near Nucla, Colorado. The station is rated at 100 MW. The unit has a circulating fluidized bed boiler that provides steam for several turbine/generators. Its projected net heat rate is 11,800 Btu/kWh, with a capacity factor of 61% and an availability of 79%; this is assumed to degrade by 5% between 2020 and 2029.
  • Springerville Station Unit 3 is a coal-fired unit located near Springerville, Arizona, at the existing Springerville Generating Station. Unit 3 is rated at 418 MW. Its projected net heat rate is 10,000 Btu/kWh with an availability of 93% and 78% capacity factor.
  • The Burlington facility consists of two oil-fired combustion turbine units near Burlington, Colorado. The station has a net summer capacity output of 100 MW, with each unit rated at 50 MW. Winter net capacity is 120 MW, with each unit rated at 60 MW. As is the case for all Tri-State simple-cycle turbines, the station is primarily used for peaking power and emergency generation, and the historical capacity factors have been less than 5% and the starting availability is been greater than 95%. The expected station net heat rate, based on past operation, is 11,300 Btu/kWh at full load.
  • The Pyramid generating facility is a dual-fuel, simple-cycle, combustion turbine facility located near Lordsburg, New Mexico. The station consists of four General Electric LM6000 combustion turbines that can run on natural gas or fuel oil and are rated at 40 MW each for a net dependable plant output of 160 MW year round. The net heat rate of these units is 9,600 Btu/kWh on natural gas at full load operation. The historical capacity factors of these units have been less than 10% and the starting reliability of the units is greater than 95%.
  • The Rifle generating station is a combined-cycle, gas-fired combustion turbine facility located near Rifle, Colorado. The station consists of three General Electric MS5001 combustion turbines each rated at 15 MW, and one 40 MW Westinghouse steam turbine, for a total net dependable plant output of 85 MW. The station has a net summer capacity of is 77 MW. The net heat rate of the facility at full load conditions is 11,700 Btu/kWh. The average historical capacity factor of Rifle has been less than 10%.
  • The Limon generating station is a simple-cycle, dual-fuel, combustion turbine facility located near Limon, Colorado. The station consists of two General Electric 7EA combustion turbines, which can run on natural gas or fuel oil, with a rated and net dependable output of 77 MW each, for a station output of 154 MW. The station has a net summer capacity of is 128 MW. The expected net heat rate of the facility at full load conditions is 10,600 Btu/kWh on natural gas. The historical capacity factor of Limon has been less than 10%, and the starting reliability of the units is greater than 95%.
  • The Knutson station is a simple-cycle, dual-fuel, combustion turbine facility located near Brighton, Colorado. It consists of two General Electric 7EA combustion turbines that can run on natural gas or fuel oil, with a rated and net dependable output of 77 MW each, for a station output of 154 MW. The station has a net summer capacity of is 128 MW. The net heat rate of the facility at full load conditions is 10,600 Btu/kWh. The historical capacity factor of the Knutson units has been less than 10% and the starting reliability of the units is greater than 95%.
  • In 2011, Tri-State purchased the J.M. Shafer combined-cycle plant located in Fort Lupton, Colorado. It was formerly known as Thermo-Cogen Partners. Tri-State will receive 150 MW of capacity and energy until June 30, 2019. Starting July 1, 2019, Tri-State will receive all 272 MW of output from JM Shafer.

Tri-State said in the plan that if the U.S. Environmental Protection Agency’s recently-final Clean Power Plan (CPP) places existing generation resources at risk, then Tri-State and other utilities must be ready to continue to satisfy customer needs for electricity through the development of demand side and supply side resources. In order to have the ability to construct new supply-side resources, site development work must occur years in advance of the commercial operation of new generation facilities. As a result, Tri-State said it will be engaged in continuing planning and development activities for new generation resources.

From the analysis presented in this document, and based on the base-case load forecast, Tri-State is now projecting it will not need additional generation resources until approximately 2023. Of course that date could be accelerated or delayed based on higher/lower load growth, or any number of other causes that would result in current assumptions or forecasts being off-target, the cooperative added.

About Barry Cassell 20414 Articles
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 24 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.