Longroad Energy Secures Power Purchase Agreement for Hybrid Solar and Storage Project in California with Marin Clean Energy

Longroad Energy has secured a power purchase agreement (PPA) for its hybrid solar and battery energy storage system (BESS) project located in San Benito County, California, with Marin Clean Energy (MCE), a not-for-profit electricity provider. This agreement pertains to Longroad’s Allium hybrid project and was discussed during MCE’s Technical Committee Meeting on February 7, 2025.

This contract marks the first time Longroad has integrated energy storage into a project contracted with MCE. Previously, MCE was the sole offtaker for Longroad’s operational 160 MW solar-only Little Bear project in Fresno County, California, under four separate busbar PPAs. Established in 2010, MCE became the first community choice aggregator (CCA) in California, providing an alternative electricity source for local communities in place of investor-owned utilities (IOUs). According to the California Community Choice Association (CalCCA), there are now 25 CCAs across the state serving over 14 million customers.

Full-toll Agreement Set to Begin in 2031

MCE selected the Allium project during its 2024 annual Open Season procurement, where it sought bids for new renewable energy developments. Under this full-toll agreement, MCE will receive portfolio content category 1 energy, resource adequacy (RA), and ancillary services from Longroad’s project, which combines a 110 MW/440 MWh lithium-ion BESS with a 110 MW solar farm. MCE will pay Longroad a fixed price without any escalation for the 20-year term, commencing on May 1, 2031.

Although the project is still in its early stages, Longroad has secured full site control and Transmission Plan Deliverability from the California Independent System Operator (CAISO). The company aims to begin construction in July 2026. This tolling arrangement resembles another agreement MCE has with Arevon Energy for its 250 MW/1,000 MWh Cormorant BESS in San Bernardino County.

Extended Timeline for System Upgrades

The extended development timeline for the Allium project allows for necessary upgrades to the CAISO grid interconnection. Longroad submitted an interconnection request for the Allium project in 2021 as part of CAISO’s oversubscribed Cluster 14 window, which aims to connect 110 MW of both solar and storage to the grid via Pacific Gas & Electric’s (PG&E) Crazy Horse Canyon – Hollister 115 kV transmission line. Longroad expects to finalize an interconnection agreement with CAISO and PG&E by January 2026. Cluster 14, which CAISO refers to as its first “supercluster,” has experienced delays due to a 241% increase in submissions compared to the previous year.

Longroad’s U.S. Storage Developments

In addition to its California efforts, Longroad is currently in negotiations with Hawaiian Electric Company (HECO) regarding agreements for two of its solar-BESS hybrid projects on separate Hawaiian islands. The larger project, Mahi Solar and BESS, consists of a 120 MW/480 MWh BESS co-located with a similarly sized solar project on Oahu. The smaller project, Pulehu Solar and BESS, features a 20 MW/80 MWh storage facility paired with a 20 MW solar farm on Maui.

These agreements are part of HECO’s 2021 Stage 3 RFP procurement, although both projects were previously selected in a 2019 procurement before the COVID-19 pandemic and the subsequent supply-chain crisis. Due to the challenging market conditions, Longroad sought price increases and extensions for guaranteed commercial operation dates (GCODs), but HECO ultimately rejected these amendments, rendering the PPAs null and void. Longroad and HECO are now aiming for the Mahi and Pulehu projects to come online in 2027.

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