Longroad Energy has secured a power purchase agreement (PPA) for one of its hybrid solar and BESS projects located in San Benito County, California with not-for-profit electricity provider Marin Clean Energy (MCE).
The details of the agreement, which relate to Massachusetts-based independent power producer (IPP) Longroad’s Allium hybrid project, were discussed at MCE’s recent Technical Committee Meeting held 7 February 2025.
Enjoy 12 months of exclusive analysis
- Regular insight and analysis of the industry’s biggest developments
- In-depth interviews with the industry’s leading figures
- Annual digital subscription to the PV Tech Power journal
- Discounts on Solar Media’s portfolio of events, in-person and virtual
Or continue reading this article for free
This isn’t the first Longroad-developed project to be contracted with MCE but is the first to incorporate storage. MCE is the sole offtaker of Longroad’s operational 160MAac solar-only Little Bear project located in Fresno County, California under four busbar separate PPAs.
Formed in 2010, MCE became the first community choice aggregator (CCA) in the State of California providing electricity for local communities as an alternative to investor-owned utilities (IOUs). According to the body representing the interests of all California CCAs, the California Community Choice Association (CalCCA), there are now 25 different CCAs across the State serving over 14 million customers.
Full-toll agreement commencing delivery in 2031
The project was selected by MCE as part of the CCA’s 2024 annual Open Season procurement, seeking bids from developers of new-build renewable energy developments.
Under the terms of the agreement, described as being full-toll, MCE will have access to portfolio content category 1 energy, resource adequacy (RA), and ancillary services from Longroad’s Allium Hybrid project which pairs a 110MW/440MWh lithium-ion BESS with a 110MW solar farm.
MCE will pay Longroad a fixed price with no escalation for the 20-year term of the agreement, which is set to commence 1 May 2031.
Although the project is described by MCE as being at an early stage of development, Longroad has already secured full site control along with Transmission Plan Deliverability from the California Independent System Operator (CAISO). Longroad hopes to commence construction on the project during July 2026.
The tolling arrangement is similar to another agreement MCE holds with another developer, Arevon Energy, relating to its 250MW/1,000MWh Cormorant BESS in San Bernardino County, as reported by Energy-Storage.news last April.
Longer development timeline to allow for system upgrades
According to the agenda packet for MCE’s recent technical meeting, the longer project development timeline allows the necessary system upgrades for California Independent System Operator (CAISO) grid interconnection to be completed.
Longroad submitted an interconnection request with CAISO for its Allium project in 2021 as part of the system operator’s massively oversubscribed Cluster 14 window for 110MW of both solar and storage connecting to the grid via Pacific Gas & Electric’s (PG&E’s) Crazy Horse Canyon – Hollister 115kV transmission line.
The developer expects to execute an interconnection agreement with CAISO and PG&E for its Allium project in January 2026. Dubbed by CAISO as its first “supercluster”, Cluster 14 has been delayed after the system operator saw a 241% increase on the number of submissions compared to the previous year.
Longroad US storage developments
Elsewhere in the US, Longroad is currently negotiating with Hawaiian Electric Company (HECO) over the terms of agreements relating to offtake from two of the developer’s solar-BESS hybrid projects located on separate Hawaiian islands.
The larger of the two projects, dubbed Mahi Solar and BESS, comprises a 120MW/480MWh BESS co-located with a similarly sized solar project located on the island of Oahu. The second smaller project, known as Pulehu Solar and BESS, is made up of a 20MW/80MWh storage facility paired with a 20MW solar farm on the island of Maui.
Although the agreements are being negotiated as part of HECO’s 2021 Stage 3 RFP procurement, both projects were already successful in being selected as part of previous procurement issued by the investor-owned utility (IOU) in 2019. Crucially, the contracts were awarded before the Covid-19 pandemic, and before the global supply-chain crisis which lead to higher prices and longer lead times from equipment suppliers.
After being selected for the procurement and in order for both projects to remain viable, Longroad sought PPA price increases and extensions to guaranteed commercial operation dates (GCODs). However, HECO ended up rejecting these amendments, leading to both PPAS being declared null and void.
Longroad and HECO are targeting 2027 online dates for the Mahi and Pulehu projects.
San Francisco, California-headquartered Clearway Energy had three of its projects selected as part of HECO’s Stage 3 RFP, which the developer has since withdrawn after citing the IOU’s “ongoing financial uncertainty”, as reported by Energy-Storage.news during the final quarter of last year.
