FERC has approved an agreement between Southern California Edison and Longroad Development Co. regarding interconnection of a 500-MW battery energy storage project, with one commissioner acknowledging Longroad remains “between a rock and a hard place.”
In an April 10 order (ER26-518), FERC accepted a design, engineering, procurement and construction letter agreement between SCE and Longroad Development related to Longroad’s Rosa storage project, to be built in Moorpark, Calif.
The letter addresses shared network upgrade obligations for Longroad’s project under the CAISO tariff and SCE’s transmission owner tariff.
SCE filed the agreement with FERC for review in November 2025 because it differs from the pro forma agreement for interconnections SCE developed in response to FERC Order 2003. The agreement remains unexecuted after SCE and Longroad hit an impasse in negotiations in 2025.
Longroad submitted an interconnection request to CAISO during the Cluster 14 application window. The project was assigned a share of reliability network upgrades based on Cluster 14 interconnection studies. The Rosa project is “parked” in CAISO’s interconnection queue.
According to SCE’s filing, Longroad objects to the project payment schedule and requirement to post collateral to secure funding for its portion of the shared upgrades. Longroad said it planned to wait for the results of CAISO’s second deliverability allocation cycle to determine the commercial viability of the project before moving forward. Until that step is completed, Longroad doesn’t want to post $18.75 million in collateral.
Longroad posted $8.74 million for the project’s first financial security payment in 2023. The company argued that Appendix DD of the CAISO tariff — which applies specifically to customers parked in the Cluster 14 queue — establishes “a defined sequence” for interconnection financial security obligations, with the second payment preceding the third.
The CAISO tariff “links higher financial commitments to increasing informational certainty,” Longroad said.
In its own filing, CAISO said Longroad had misinterpreted the tariff.
“The bulk of Longroad’s protest argues that its election to park its project to reseek deliverability takes precedence over its obligation to finance its portion of shared network upgrades that ‘first-ready’ interconnection customers need to remain on schedule,” the ISO wrote. “These arguments contradict the plain language and intent of the CAISO tariff.”
The ISO said 64 interconnection customers in Cluster 14 completed all obligations, including financing, and 27 others withdrew.
In accepting the agreement between SCE and Longroad, FERC found it just and reasonable and not unduly discriminatory or preferential. The commission disagreed with Longroad that there is a defined sequence to the second and third financial security postings in the CAISO tariff.
Commissioner David LaCerte concurred with the order but issued a separate statement. He said CAISO’s tariff recognizes the importance of timely and efficient interconnection, particularly when it comes to shared network upgrades.
But two provisions of CAISO’s tariff “have placed Longroad between a rock and a hard place,” LaCerte said.
“Longroad is forced to choose between: (a) making an $18.75 million third milestone security payment for shared network upgrades before knowing whether it will have the transmission deliverability to utilize those upgrades; and (b) not making an $18.75 million third security payment for shared network upgrades, withdrawing from the queue and forfeiting its first milestone security payment,” LaCerte wrote.
“Should Longroad choose to play the long game and try again to interconnect to the CAISO grid in a later queue cluster … its odds of obtaining deliverability may be improved,” he added.
