LS Energy Solutions to construct large-scale energy storage to serve CAISO market


LS Energy Solutions (LS-ES), a specialist in grid-connected energy storage solutions, is deploying 200 MW/400 MWh of energy storage to a site in Southern California.

Construction of the project, called Big Rock, will soon be underway and is expected to be online in the second half of 2024. The project will use 137 of the company’s AiON-ESS units, which can store energy for two-hour duration, LS-ES reports.

The AiON-ESS Energy Series is all-in-one integrated system, according to LS-ES, which uses the company’s third-generation string inverters, together with lithium-ion batteries in a single, scaleable enclosure. The AiON integrated solution is also available with lithium-ferro-phosphate (LFP) battery chemistry.

The Big Rock units have a power rating of 1.5 MW and can store 3.5 MWh. Along with tier-1 lithium-ion batteries, the 137 containers include over 1,300 of LS-ES’s modular 140 kVA AiON-SIS string inverters installed inside an air-cooled section of the container, together with a liquid-cooled DC battery compartment. LS-ES reports that the DC battery strings are aggregated in small groups to keep the DC bus voltage at lower, safer levels, and that system can operate from 200 VDC up to 1500 VDC.

As with other AiON-ESS Energy Series installations, the Big Rock installation will integrate DC and AC components inside each container and provide AC output ready to be fed into medium voltage transformers.

The Big Rock energy storage project, located in Imperial County, will provide resource adequacy (RA) and ancillary services to the CAISO market, adding to the 5.6 GW of energy storage already in place. Big Rock will be operated at 100 MW of deliverability to supply 400 MWh and meet the four-hour discharge needs of an RA contract.

The project is being developed by Gore Street Energy Storage Fund, which acquired the site in February 2023 from Avantus, which will continue to provide administrative and development services for the installation. Big Rock joins other energy storage investments by the Gore Street Energy Storage Fund in Texas, Ireland, Great Britain, and Germany.

“The Big Rock project marks GSF’s most recent acquisition, and the company’s biggest to date,” said Alex O’Cinneide, CEO of Gore Street Capital. “As the company’s first project in California, Big Rock will be an important addition to the CAISO grid, helping to deliver stability to a rapidly decarbonising energy system.”

In addition to supplying AiON-ESS containers, LS-ES also expects to provide commissioning support and operations and maintenance services for the life of the project.

LS-ES currently has over 1.5 GW and 2.5 GWh deployed across 300 projects. One of those projects, which also uses AiON-ESS storage systems, is located at Fort Detrick in Frederick, Maryland, also home to a 18.6 MW  solar installation. The U.S. Army contracted with LS-ES to help further lower the garrison’s total electricity spend, achieved through participation in frequency regulation, demand response, and energy supply markets within PJM, a wholesale electricity market. The storage system was designed to be microgrid-ready to support Army’s resiliency goals.

Visitors to RE+ 2023, taking place September 11-14 in Las Vegas, can see one of the AiON-ESS containers being used in the Big Rock project. The unit will be on display at the ACE Engineering booth at 17114, with representatives of Gore Street Capital also onsite during the event.

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