Tri-State Generation and Transmission Association, increasingly under pressure from its members and renewable energy advocates for its reliance on coal, plans to close two of its coal-fired power plants and a coal mine in Colorado and New Mexico.

Tri-State said Thursday it will close the Escalante Station in northwest New Mexico by the end of this year. It intends to close its operations at the Craig Station plant in Craig and at the Colowyo Mine in northwest Colorado by 2030.

The earlier-than-planned closures are part of the utility’s larger Responsible Energy Plan, Tri-State CEO Duane Highley said during a call with reporters. He said Tri-State will release details Jan. 15 about adding more renewable energy to its system and meeting state goals for reducing greenhouse gas emissions.

The closures will affect a total of about 600 employees. Tri-State has committed to contributing $5 million to help communities and workers in New Mexico. Highley said the utility will work with state officials and communities to help with the transition in Colorado, as well.

While phasing out its coal operations will help Tri-State cut greenhouse gas emissions and address members’ calls for more renewable energy, Highley said the utility’s board has made clear that it must also deliver affordable, reliable power. He said Tri-State believes it will be able to do that.

Proposals for new renewable projects are coming “in at such a low rate” that Tri-State might be able to more quickly write off the costs of closing down the coal plants and mine, Highley added.

Last year, the Westminster-based wholesale power provider shut down its Nucla coal plant in western Colorado, ahead of plans to close it in 2022. It previously had said it will close one unit of the Craig plant by the end of 2025.

Thursday’s announcement applies to the remaining two units at the Craig facilities owned by Tri-State, a not-for-profit cooperative that serves a total of 43 electric associations in Colorado, Wyoming, New Mexico and Nebraska.

The original closing dates for the plants were: Craig Unit 2, 2038; Craig Unit 3, 2044; and Escalante, 2045.

Tri-State’s announcement received a shoutout from Gov. Jared Polis during his State of the State speech at the Capitol.

“Just this morning, Tri-State and its members announced that they will be replacing their remaining coal power in the state with thousands of megawatts of cheaper and cleaner renewable energy sources by 2030, resulting in a 90% reduction in the utilities’ in-state greenhouse gas emissions,” Polis said.

Last year, Polis released unveiled a road map for reaching his goal of making Colorado’s electric grid fossil-fuel-free by 2040. He said Thursday that he will work with Tri-State and other utilities to help the workers and communities deal with the closing of coal mines and plants.

The Colorado Mining Association said it believes closing the coal facilities will hurt electricity customers in the state and the communities that have built their economies on the industry.

“The lower costs afforded by plants such as Craig Station currently help to balance the increased costs of adding renewable energy and transmission to the system,” the association said in a statement.

The International Brotherhood of Electrical Workers Local Union 111 said it would like to see legislation with safeguards to support its members and ensure work on renewable energy projects is done with “in-state, well-trained” labor like the people it represents.

Tri-State’s announcement comes as the power supplier faces more possible defections of member electric associations because of disputes about rates and the desire to get more power from renewable energy sources.

United Power, based in Brighton, and the La Plata Electric Association in Durango have asked the Colorado Public Utilities Commission to make Tri-State say how much money it would take to break their contract. The Delta-Montrose Electric Association has reached an agreement to leave Tri-State.

In 2016, the Kit Carson Electric Association paid $37 million to break its contract with Tri-State. Kit Carson, like Delta-Montrose, complained that Tri-State’s rates were too high and wasn’t moving quickly enough to reduce its use of coal and increase the use of renewable energy.

Rates paid by Tri-State members are more than 20% above average and appear to be spurring efforts to leave the utility to find alternative energy sources, Standard and Poor’s said in November when it downgraded the power provider’s long-term credit rating from A to A-.

However, Tri-State has pointed to its addition of more renewable energy, which it says makes up about a third of its power. It says it generates more than 475 megawatts of electricity from wind, solar and other renewable sources, or enough power for about a half-million homes.

Environmental organizations welcomed Tri-State’s news of the closures, although the Sierra Club said the utility should go further.

“From member co-op unrest, to the poor economics of coal and environmental policy pressures, Tri-State can no longer ignore the benefits of retiring its coal and replacing it with local, clean energy,” Anna McDevitt of the Sierra Club said in a statement.

A 2019 study commissioned by the Sierra Club said Tri-State members could save more than $1 billion if two units of the utility’s Craig plant were replaced with wind power by 2023. The report said another $424 million could be saved if Tri-State phased out its operations at the Springerville coal plant in Arizona.

Tri-State is also a co-owner of the Laramie River Station coal plant near Wheatland, Wyo.

Western Resource Advocates said closing the coal-fired plants is an important step in helping Tri-State reduce its carbon dioxide emissions, other pollutants and lower its members’ costs.

A 2018 report by the Rocky Mountain Institute said Tri-State could save more than $600 million through 2030 if it increased its use of renewable energy. The institute is an independent think tank and research organization that focuses on moving from fossil fuels to renewable energy.