The Colstrip Steam Electric Station in Rosebud County is one of the largest coal-fired power plants in the western United States.
Units
The plant originally had four units. Units 1 and 2, the oldest, closed in early 2020. Units 3 and 4 keep operating, fueled by coal from the nearby Rosebud Mine.
Ownership
Units 3 and 4 have several co-owners, including Pacific Northwest utilities and NorthWestern Energy. Ownership shares have changed in recent years, and some West Coast owners face state laws requiring them to stop serving customers with coal power. Current ownership is laid out in utility and PSC filings.
Why it matters
- Local economy: the plant and mine are major employers and taxpayers in Rosebud County and support the Colstrip school district.
- Grid: the Colstrip transmission system connects eastern Montana generation to the Pacific Northwest.
- Environment: air-quality rules, coal-ash cleanup and greenhouse-gas policy all bear on the plant’s costs and lifespan.
What to watch
Federal air-rule changes, utility resource plans, and state legislation on the plant’s future.
For more background, see our explainers on how federal environmental rules reach Montana and Montana wind power. Find more stories in our Energy & Environment section.
Sources
- U.S. EIA, Montana profile: https://www.eia.gov/state/?sid=MT
- Montana PSC dockets: https://psc.mt.gov/
- Montana DEQ, Colstrip remediation: https://deq.mt.gov/