US power producer Talen Energy Supply and developer Pattern Energy plan to build a 600MW wind farm in Montana to “complement” an existing coal plant.
The companies plan to jointly develop the 600MW Silverthorn wind farm in Rosebud and Treasure counties. It is expected to feed into the grid at the substation of the Colstrip power station.
Talen Energy will buy out Puget Sound Energy’s 25% stake in two 740MW units of the Colstrip, boosting its holding to 55% from 31 December 2025.
Talen and Pattern expect to invest up to $1 billion in the project. It is unclear what percentage of the wind farm each party will own.
Pending permitting approvals, the two companies expect the wind farm to be online in 2026.
The first two Colstrip coal plant units – with a combined capacity of 614MW – were retired in early 2020. There is no retirement date planned for units 3 and 4, a Talen spokesperson said.
Talen sees the wind farm “complementing, not replacing” the coal generation. A spokesperson added: “We anticipate Colstrip Units 3 and 4 operating to help maintain grid stability and to generate energy for Montanans during periods of high demand.”