BILLINGS, Mont. (AP) — A Washington state electric utility signed a contract to purchase hydroelectric power from a Montana tribal company.

Puget Sound Energy Inc. signed the 15-year contract to draw power from a project operated by Energy Keepers Inc., owned by the Confederated Salish and Kootenai Tribes in Montana, The Billings Gazette reports.

The Selis Ksanka Qlispe hydroelectric project, which includes a Flathead River dam, will provide 40 megawatts of power to Puget.

The deal will supplant Puget’s delivery of coal-fired electricity from the Colstrip Power Plant in Montana after 2025.

Washington utilities face a 2025 deadline to stop billing customers for coal power under the state’s Clean Energy Transformation Act, which requires electricity to be free of greenhouse gas emissions by 2045.

Puget is cutting its coal ties. The Bellevue, Washington, utility agreed to sell its 25% share of Colstrip Unit to NorthWestern Energy Corp., pending regulatory approval.

Energy Keepers in Polson, Montana, is benefiting from the move away from coal. The company finalized the deal with Puget in February and began supplying energy in March.

Several large Montana customers that previously bought electricity from Talen Energy Corp., which sells the Colstrip plant’s power, have been picked up by Energy Keepers, an official said.