On August 29, 2025, FERC issued three orders accepting tariff revisions proposed by PacifiCorp and Portland General Electric (“PGE”) to enable both utility’s participation in the California Independent System Operator Corporation’s (“CAISO”) Extended Day-Ahead Market (“EDAM”) and accepting CAISO’s proposed tariff revisions which modify the EDAM’s allocation of congestion revenues. The three orders issued by FERC clear the way for PacifiCorp and PGE, the first two entities to file tariff revisions to participate in the EDAM, to enter the market in 2026.
FERC previously approved the CAISO’s tariff revisions to establish the EDAM design on December 20, 2023. The EDAM enables entities outside of the CAISO BAA to participate in the CAISO’s day-ahead market, much like the current Western Imbalance Market (“WEIM”) extends participation in the CAISO’s real-time market.
The first such utility to propose OATT revisions to enable EDAM participation was PacifiCorp. PacifiCorp was the first entity to announce its intention to join the EDAM in 2022, stating that its participation in the EDAM would expand upon its successful participation in the WEIM to benefit customers. PacifiCorp filed proposed tariff revisions in early 2025 to enable its participation in the EDAM. PacifiCorp argued its participation in the EDAM will bring cost savings for its customers as well as improved operational efficiencies and integration of new resources. FERC accepted PacifiCorp’s proposed Tariff revisions as just and reasonable.
PGE was the second utility to file proposed OATT revisions to enable its participation in the EDAM, filing in April of 2025. PGE stated in its filing that joining the EDAM would build upon its success in the WEIM and adequately serve load growth in a manner that optimizes usage of available resources and transmission.
In its orders, FERC directed both utilities to report on several aspects of EDAM performance following market entry.
In the third order, FERC addressed a filing by the CAISO to amend the EDAM’s congestion revenue allocation methodology, such that congestion revenues among parallel flows would be paid by the BAA incurring such congestion costs, instead of where the congestion itself was located. FERC accepted the tariff revisions as just and reasonable, finding the change will permit eligible transmission customers to adequately hedge against congestion charges.
FERC’s order accepting PacifiCorp’s tariff revisions, issued in Docket No. ER25-951, is available here. FERC’s order accepting PGE’s tariff revisions, issued in Docket No. ER25-1868, is available here. FERC’s order accepting CAISO’s tariff revisions, issued in Docket No. ER25-2637, is available here.
