Tri-State Generation and Transmission Association, the state’s second largest electricity provider, has announced plans to shut down its last coal-fired power plant in Craig, Colorado, in early 2028. That's two years earlier than previously scheduled.
The proposal, which is part of an updated Energy Resource Plan (ERP) submitted to state regulators last week, also includes plans for major new investments in renewable energy and natural gas-fired units.
Lee Boughey, Tri-State’s director of communications, said the updated ERP represents the latest iteration of a clean energy transition plan that the utility, which provides wholesale electricity to 45 members — mostly rural electricity cooperatives — across Colorado, Nebraska, New Mexico and Wyoming, first developed in 2019.
Tri-State's updated ERP comes as utilities big and small around the state plan for a vastly changed energy future shaped by climate action goals at the local, state and federal levels. Those plans call for a rapid transition to 100% renewable energy sources in the near term, even as demand on the grid is expected to grow with the rise of electric vehicles and building electrification, making the reliability of our electricity systems more urgent than ever.
Boughey said the new plan was designed to be responsive to the demands of the utility's members.
“Our members, representing rural residents from across the West, have asked Tri-State…to make a clean energy transition, but keep their power reliable and keep it affordable,” Boughey said.
The original clean energy transition plan aspired to retire the Craig coal plant by 2030. Boughey said market conditions have changed significantly since 2019, though, and it now makes more sense to accelerate the closure.
“The decision to close any power plant is taken very seriously,” he said. “We forecast where prices are going to be. We forecast where markets are going to be.”
Boughey cited two major market developments that moved the needle in favor of the accelerated clean energy transition plan. For one, the cost of wind and solar dropped precipitously over the past decade, often making renewable energy more competitive than fossil fuel-based power. In addition, Tri-State will see reduced demand for power as several rural electric cooperative members are ending their contracts with the utility over the next couple of years. Some of those member coops have cited a desire for more stable costs, more flexibility, and a cleaner energy mix as the reason for their split from Tri-State
“If you combine the economics, the availability of low-cost power, and our reduced load, it calls for the retirement of Craig Station fully in 2028,” he said.
Boughey said the plan is expected to save ratepayers more than $1.8 billion through 2043.
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To further augment those savings, Boughey said Tri-State is planning to tap into federal funding from the United States Department of Agriculture’s Empowering Rural America (ERA) program, a part of the Inflation Reduction Act intended to help rural communities transition to clean energy.
As the coal plant shuts down, much of the power it generates will shift to renewable energy. Tri-State has plans to increase its renewable energy and energy storage portfolio by 1,250 megawatts by 2031. The proposal also includes a new 290 megawatt natural gas-fired unit.
Boughey said the new plan has many benefits.
“Economics is the key driver. But it also reflects our work to reduce greenhouse gas emissions,” he said.
Utility officials estimate the clean energy transition plan would reduce Tri-State’s carbon footprint by 89% compared to a 2005 baseline and put the energy association on a path to provide 70% of its power from renewable energy by 2030. That projected progress has earned the support of a broad coalition, including environmental groups like the Sierra Club and Western Resource Advocates (WRA).
Sarah Clark, the Sierra Club’s Colorado field manager, applauded Tri-State’s proposal.
“If Tri-State’s proposal is approved, Colorado's communities will be healthier, the state's air will be cleaner, and Tr-State's customers will save money,” she said. “Overall, I think this is great news…It's really going to help ratepayers and our climate.”
In a press release, Stacy Tellinghuisen, deputy director of policy development at WRA, commended Tri-State for developing a plan “which will reduce carbon pollution across the West and provide economic benefits for its member cooperatives.”
The plan also calls for accelerated closure of Tri-State’s Springerville plant, a 458-megawatt coal-fired power plant in eastern Arizona. When that plant shuts down in 2031, the utility will have one remaining coal resource located in Wyoming.
The updated ERP requires the approval of Colorado’s Public Utility Commission, which will consider the new plan next year.
