Public Service Company of New Mexico to Join California Grid Operator’s Extended Day Ahead Market

The Public Service Company of New Mexico (PNM) has announced its commitment to the California Independent System Operator’s extended day-ahead market, or EDAM. PNM’s commitment, formalized with a signed agreement, initiates an important step in the governance of the Western Energy Markets. Although PNM will join EDAM in 2027, the governance change takes effect immediately.

The West-Wide Governance Pathways Initiative was developed in 2023 to maximize the benefits of wholesale electricity markets through a new governing organization. The initiative’s Step 1 proposal received approval in August 2024 to create a more independent and regional approach to make market decisions involving the Western Energy Imbalance Market, or WEIM, and EDAM.

The WEM Governing Body now holds primary decision-making authority over ISO tariff provisions that apply to both WEIM and EDAM. PNM’s commitment ensures the market will include a geographically diverse group of non-ISO entities whose combined annual energy load exceeds 70 percent of the load served by the ISO, meeting the requirements of the Pathways proposal.

The PNM is the seventh utility to formally commit to participate in EDAM. It joins Portland General Electric, PacifiCorp, the Balancing Authority of Northern California, the Turlock Irrigation District, the Los Angeles Department of Water and Power and the Imperial Irrigation District.

Day-ahead energy markets enable firms to trade electricity at set prices for delivery the following day. This allows both buyers and sellers to hedge against fluctuations and volatility in real-time electricity prices.

Last November, PNM announced plans to join the EDAM. At the time, the company estimated that participation in the day-ahead market could bring approximately $20 million in annual benefits to its customers. Since joining the Western Energy Imbalance Market (WEIM) in 2021, PNM has already seen nearly $125 million in benefits. According to the most recent WEIM Quarterly Benefits Report published in April, that total has since increased to around $170 million. PNM will participate in the EDAM during 2027; however, the governance change is effective immediately.

EDAM, set to launch in 2026, builds on the success of the WEIM, a real‑time market that began in 2014 and has delivered around $7 billion in cumulative benefits. The WEIM has also bolstered grid reliability by enabling regional balancing authorities to work together more effectively and by facilitating energy transfers across its footprint exactly when and where they’re needed.

Independent analysis predicts that EDAM will bring additional reliability and cost‑saving gains for consumers. By shifting more transactions into the day‑ahead market, EDAM allows energy to be scheduled and coordinated in advance—unlocking greater efficiency and regional collaboration to reduce costs.