Talen Energy Supply LLC (TES) and Puget Sound Energy (PSE) have executed a strategic transaction regarding TES’ asset in Colstrip, Mont. The transaction seeks to leverage the plant’s existing electric infrastructure for utility-scale renewables project development while preserving grid resiliency for the Western Interconnection.
Under the terms of the transaction agreement, TES affiliate Talen Montana LLC (TM), which currently owns a 30% share (approximately 222 MW) of Colstrip Unit 3 and serves as the plant operator, will assume PSE’s 25% ownership share in Units 3 and 4 (approximately 370 MW) on December 31, 2025. PSE will retain its share of environmental remediation and other asset retirement obligations, decommissioning costs and other appropriate costs associated with Units 3 and 4 that accrue through December 31, 2025.
Talen’s Colstrip energy transition plan centers on the development of the 600 MW Silverthorn Wind project located in Rosebud and Treasure counties, which is expected to interconnect at the Colstrip substation.
The Silverthorn project is part of a joint venture between TES affiliate Cumulus Renewables and Pattern Energy Group LP and, pending approvals, is expected to be commercially available beginning in 2026.
When complete, Silverthorn will complement TM’s share of Colstrip Units 3 and 4 by reducing the overall carbon intensity of TES’ Montana electric generation while also ensuring grid resiliency and providing the reliable energy that Montana needs to power its economy. Pattern Energy and Talen are expected to invest up to $1 billion in this energy transition plan and the Silverthorn project to serve customers.
“I am pleased to complete this strategic transaction with Mary Kipp and Puget Sound Energy, which allows Talen to begin implementing its energy transition vision for Colstrip while also helping to preserve energy security and jobs in Montana,” says TES CEO Alejandro “Alex” Hernandez. “I would also like to thank Governor Greg Gianforte for his continuing support of Colstrip and for working with the Colstrip co-owners as an advocate that Colstrip operate for its full, useful life. This strategic transaction is a tangible example of energy transition, balancing the interests of our various stakeholders and communities, while creating an attractive renewable energy investment opportunity for infrastructure capital partners.”
“PSE customers want clean energy and we are committed to providing it as we plan for our future in accordance with Washington laws and our aspirational Beyond Net Zero Carbon goal,” comments Mary Kipp, CEO of PSE.
“Our partnership with Talen Energy to facilitate the energy transition of Colstrip with our Silverthorn Wind project will make Colstrip one of the most important energy centers in the United States, serving the rapidly growing energy needs of the West,” adds Mike Garland, CEO of Pattern Energy. “The Silverthorn project is of similar scale to our recent Western Spirit Wind facility with 1,050 MW of capacity, the largest wind power project ever constructed as a single phase in the Americas. As we embark on Silverthorn, we commend Talen for driving this energy transition plan.”
Consistent with the terms of the ownership and operating agreement of Colstrip Units 3 and 4, the transaction is subject to a 90-day review period which allows other Colstrip co-owners to exercise their right of first refusal to join the transaction and acquire an interest in the ownership share being transferred. The transaction is subject to approval by the U.S. Bankruptcy Court for the Southern District of Texas, which is currently presiding over TES’ strategic recapitalization.