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December 5, 2025

Western Energy Imbalance Market (WEIM)

© RTO Insider LLC
Pathways Initiative Unveils RO Proposed Name, Bylaws
The West-Wide Governance Pathways Initiative is preparing to file the incorporation documents for the independent RO that will govern CAISO’s energy markets, while funding challenges remain.
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FERC OKs Imperial Irrigation District’s WEIM Agreement

FERC approved CAISO's Western Energy Imbalance Market implementation agreement with Imperial Irrigation District.

NorthWestern Energy
Black Hills-NorthWestern Merger Could Reshape Western Market Map

The proposed merger between Black Hills Corp. and NorthWestern Energy likely will reshape the map in the competition between CAISO’s Extended Day-Ahead Market and SPP’s Markets+ — but it’s still too early to know where new boundaries will be drawn.

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State Tx Entity, Regional Markets Feature in Ore. Energy Strategy
The Oregon Department of Energy’s new draft energy strategy points to the importance of new transmission development and expanding electricity markets for meeting the state's energy goals.
Office of Gov. Gavin Newsom
Newsom Reiterates Support for Western Regional Market Push
California Gov. Gavin Newsom again appeared to voice support for the proposed bill that would allow CAISO to relinquish market governance to an independent regional organization, saying the legislation can reduce electricity costs and improve reliability.
CAISO
WEIM Q2 Benefits Exceed $420M, as Total Tops $7.4B
CAISO’s Western Energy Imbalance Market provided participants with $422.44 million in economic benefits during the second quarter of 2025, up 15% compared with the same period year earlier despite no change in membership. 
West-Wide Governance Pathways Initiative
Pathways Initiative Clarifies Near-term Division of Labor with CAISO
The West-Wide Governance Pathways Initiative will run its stakeholder processes separately from CAISO’s until the effort's regional organization is formally launched in 2028, even in areas of overlapping interest.
CAISO
Panel Ponders Impacts, Priorities Around Western Market Seams

The formation of two competing day-ahead markets will create seams across the West, but at least one utility representative is more worried about seams resulting from the fracture of CAISO’s real-time Western Energy Imbalance Market.

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Tri-State Tells Colorado PUC Joining SPP RTO in Public Interest
Tri-State asked the Colorado Public Utilities Commission to find it would be in the public interest for the power supplier to join SPP, saying integrating with the RTO would bring significant benefits.
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FERC not in Charge of Modernizing Western Grid, Christie Says

Outgoing FERC Chair Mark Christie and former Colorado Gov. Bill Ritter both emphasized that the West controls the future of the Western interconnection, not Washington.


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