FERC Orders CAISO and SPP to File Joint Report on Western “Seams” Coordination by Sept. 30

On July 16, 2026, the Federal Energy Regulatory Commission (FERC) ordered the California Independent System Operator (CAISO) and Southwest Power Pool (SPP) to submit a joint report describing how they coordinate operations at the “seams” where they meet. The report is due September 30, 2026, and FERC will accept public comments for 30 days after the report is filed. This action is Item E-2 in FERC’s July 16 decisions record under Docket No. AD26-10-000 (“Western Seams Coordination”).

What FERC ordered CAISO and SPP to do

FERC’s order requires CAISO and SPP to detail their coordination efforts along their seams—both (1) where the SPP and CAISO markets adjoin, and (2) where either market interfaces with neighboring balancing authorities.

FERC also specified the joint report must include:

• Current coordination initiatives
• Operational challenges tied to new market developments
• Plans and schedules for resolving issues
• Areas where the operators “have yet to align”

Why “seams” coordination matters for reliability and market operations

In grid terms, “seams” are the handoff points between different operators’ systems and market processes. When coordination across those interfaces isn’t clear or complete, it can complicate reliability and the predictability of how power flows and grid operations work across regional boundaries. FERC said the reporting requirement is aimed at addressing reliability and efficiency hurdles as the western grid landscape continues to evolve.

Who is affected—and what it means for power customers

The reporting requirement targets CAISO and SPP, but the practical stakes extend to utilities and other market participants that depend on stable transmission handoffs across operating- and market-region boundaries. The next step after the order is not a new rule in the abstract—it’s a specific, docketed report that documents what coordination is working, what problems remain, and what timeline the operators propose to address gaps.

Key dates: filing deadline and the limited comment window

• July 16, 2026: FERC issued the order directing the joint report (Item E-2, Docket No. AD26-10-000).
• September 30, 2026: Deadline for CAISO and SPP to file the joint report.
• 30 days post-filing: FERC will accept public comments focused on seams management and market coordination issues discussed in the report.

Importantly, FERC said the comment window is limited to the seams-management and market-coordination issues addressed in the joint report—so the next concrete opportunity for public input starts only after the filing.

What to watch next

Watch for two things in the coming months: (1) when CAISO and SPP submit their joint “seams” coordination report by September 30, 2026, and (2) the start of the 30-day comment period that follows the filing. Once the report is public, stakeholders can point to where the operators say coordination is aligned—and where they report remaining misalignments and proposed fixes.

Sources

• FERC news release on the joint “seams” coordination report (AD26-10)