Wholesale power supplier Tri-State Generation and Transmission Association said it plans to retire its remaining coal-fired power plants in Colorado and New Mexico by 2030.

The plan includes closure of a Colorado coal mine.

Tri-State said it will release in mid-January a proposal to add "significant renewable energy additions."

The wholesale generating and transmission cooperative has long favored coal to generate electricity for its 46-member network of electric distribution companies in Colorado, Nebraska, New Mexico and Wyoming. Growing demand for renewable energy resources has led some of its wholesale customers to seek other energy providers.

For example, Delta-Montrose Electric Association in Colorado and Kit Carson Electric Cooperative in New Mexico negotiated exit fees with Tri-State. In 2019, two other Colorado electric cooperatives sought to negotiate similar exit fees. All four cited their desire to procure more renewable energy as driving their decisions to separate from Tri-State.

As recently as 2017, the Kansas Supreme Court granted an air permit for a single-unit, 895 megawatt (MW) coal-fired power plant that Tri-State had been working to build for a decade. With the permit in hand, however, Tri-State told the U.S. Securities and Exchange Commission that it would write off more than $93 million it had spent on the project. It said the chances of the unit ever being built were "remote."

Power plant closures

Tri-State said in a statement that the New Mexico generating asset facing closure is the 253 MW Escalante Station, which will close by the end of 2020. The power plant was built by Plains Electric Generation and Transmission Cooperative and began operations in 1984. Plains Electric merged with Tri-State in 2000. The plant closure will impact 107 employees.

Tri-State serves electric cooperatives in four western states. Source: Tri-StateTri-State said that as part of the closure, it will address issues related to the McKinley Paper Co., which buys steam and water from Escalante Station.

Tri-State previously retired its coal ownership capacity in Unit 3 of the San Juan Generation Station in New Mexico in 2017.

In Colorado, the three-unit 1,855 MW Craig Station will close by 2030. The power plant’s units were built by Colorado Ute Electric Association and began operations between 1979 and 1984. Tri-State bought Craig Station and other assets from Colorado Ute in 1992. The power plant employs 253 people.

Tri-State previously announced that the 427 MW Craig Station Unit 1 will close by the end of 2025. The 410 MW Unit 2 and the 448 MW Unit 3 will close by 2030. Tri-State operates Craig Station and owns 24% of Units 1 and 2. Tri-State owns all of Unit 3.

In addition, Tri-State said the Colowyo Mine, which produces coal used at Craig Station, will cease production by 2030 and the site will be reclaimed. Tri-State bought Colowyo Mine from Rio Tinto in 2011. The mine employs 219 people.

Tri-State retired its coal capacity at Nucla Station in Western Colorado in 2019.