BHE Montana to Participate in CAISO’s Extended Day-Ahead Market, Expanding Reliability and Delivering Customer Benefits

GREAT FALLS, Mont.--(BUSINESS WIRE)--BHE Montana today announced it has signed an implementation agreement to participate in the California Independent System Operator’s (CAISO) Extended Day-Ahead Market (EDAM), a significant step that will enhance the company’s ability to serve customers reliably and efficiently while strengthening coordination across the Western power grid.

“The benefits already demonstrated through BHE Montana’s participation in the WEIM show the value regional coordination can deliver for customers,” said Ed Rihn, CEO, BHE Montana. “EDAM builds on that foundation by extending those efficiencies into the day-ahead timeframe, creating additional opportunities to access lower-cost resources, better manage system conditions, and support reliable electric service for Montana customers and across the region.”

EDAM will allow BHE Montana to participate in a broader regional marketplace that helps power producers and transmission providers plan and schedule energy resources one day in advance. By coordinating with a larger network of participants across the West, BHE Montana will improve the state’s access to affordable energy supplies, make more efficient use of current and planned transmission infrastructure and enhance overall system reliability. BHE Montana plans to begin participating in the day-ahead market in 2028.

The latest Western Energy Markets Quarterly Benefits Report underscores the value of regional coordination. In second quarter 2026, the Western Energy Imbalance Market (WEIM) delivered approximately $459.7 million in gross economic benefits, pushing cumulative WEIM cost savings for market participants and their customers to more than $9.08 billion since the market launched in 2014. For BHE Montana’s balancing area, those benefits totaled over $2 million since joining WEIM in May 2026. The same report showed the Extended Day-Ahead Market producing approximately $11.4 million in savings during its first two months of operation, reinforcing the promise of additional customer value as day-ahead coordination expands across the West.

“We are excited to have BHE Montana now committed to participate in both the real-time and day-ahead Western electricity markets,” said Elliot Mainzer, CAISO’s president and CEO, “and we look forward to working with them to deliver additional reliability benefits and cost savings for the company and their customers.”

By joining EDAM, BHE Montana expects to provide several key benefits for customers, including:

• Improved access to lower-cost energy resources through participation in a larger and more diverse regional market.
• More efficient use of transmission infrastructure, helping maximize the value of existing grid investments.
• Enhanced operational planning through day-ahead scheduling and coordination with neighboring utilities and market participants.
• Greater reliability and resource sharing across the Western Interconnection, particularly during periods of high demand or unexpected system events.
• Reduced exposure to real-time market volatility through improved day-ahead forecasting and resource commitments.
• Documented market savings and operational efficiencies, building on WEIM results that show large-scale regional coordination can reduce costs, support transfers across balancing areas, improve renewable integration and strengthen access to surplus energy when it is needed most.

Regional coordination through EDAM will enable participants to optimize energy transactions over a larger geographic footprint, improving system flexibility and creating opportunities to access available resources where and when they are needed most.

BHE Montana will continue working with regional partners, market operators, regulators and stakeholders as preparations for market participation move forward.

About BHE Montana

BHE Montana provides electric transmission and generation services and is committed to delivering reliable, cost-effective energy solutions that support customers, communities, and economic growth throughout Montana and the region.