Rocky Mountain Power Joins Western Day-Ahead Market

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- Rocky Mountain Power, a subsidiary of PacifiCorp, began trading Thursday night in the new Extended Day-Ahead Market running on CAISO's network, becoming "the first participant alongside CAISO" per spokesperson Omar Granados.
- PacifiCorp will shift from satisfying 3–5% of its generation and demand through broader market purchases to 100% under the new market, with savings flowing to customers as lower net power costs (per VP of energy supply management Michael Wilding).
- The Extended Day-Ahead Market gives Western utilities access to a wider pool of buyers and sellers, increasing transparency and liquidity, according to Brian Turner of Advanced Energy United.
- Wyoming's Energy Authority will monitor PacifiCorp's participation for five years to ensure the state's coal, oil, and gas sectors aren't "unfairly penalized" by climate targets in California, Oregon, and Washington (per director John Jenks).
- Wyoming electricity bills rose 5.5% from 2024 to 2025, per EIA data, and the new market may help insulate Western consumers from price spikes tied to the Iran war by letting utilities tap cheaper regional renewables instead of pricier natural gas.
- The Extended Day-Ahead Market is the first such marketplace in the West; the Southwest Power Pool is developing a separate marketplace initially involving power producers in Arizona, Colorado, and the Northwest.
Why it matters: For Wyoming ratepayers, PacifiCorp's full-market participation could translate energy-cost savings directly into bills even as prices climb — Wyoming bills already rose 5.5% in a year. For the state's fossil fuel economy, a five-year state watchdog on market outcomes reflects Wyoming's bet that cheaper regional renewables shouldn't crowd out its coal and gas generators.
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