REV Renewables (REV), an LS Power company and a developer, owner, and operator of renewable energy and energy storage projects, on June 18 said the company marked a major milestone with the commissioning of its Tumbleweed Energy Storage facility in Kern County, California. The company celebrated with a ribbon-cutting ceremony alongside local officials, community leaders, and industry partners. REV said the project is the first eight-hour battery energy storage system in California, and ushers in a new era of grid reliability and clean energy integration.
Developed in partnership with Ava Community Energy and California Community Power (CC Power) on behalf of its participating members CleanPowerSF, Peninsula Clean Energy, Redwood Coast Energy Authority, San José Clean Energy, Silicon Valley Clean Energy, Sonoma Clean Power, Valley Clean Energy, all Community Choice Aggregators (CCAs) serving Northern California, the project was brought online ahead of California Public Utilities Commission’s (CPUC) requirements. The early delivery underscores the partners’ shared commitment to accelerating the state’s clean energy transition while enhancing grid resilience.
The Tumbleweed facility represents a significant shift in how battery storage supports the electric grid. While energy storage projects just five years ago primarily provided ancillary grid services lasting seconds or minutes, the industry has evolved toward four-hour systems capable of delivering energy over extended periods to support grid operations and reliability. At eight hours, Tumbleweed is among the first projects capable of bulk-shifting solar energy generated during the day to power homes and businesses overnight, helping to reduce emissions while strengthening grid reliability.
“As the first eight-hour, long-duration energy storage project developed under the California Public Utilities Commission’s Integrated Resource Plan procurement requirements, Tumbleweed demonstrates how forward-looking policy can most affordably accelerate deployment of the next generation of grid infrastructure,” said Leuwam Tesfai, the CPUC’s executive director. “These types of projects will help create a more resilient, reliable, affordable, and carbon-free electric system for California communities.”
Unlike shorter-duration systems, eight-hour storage further matures the role batteries play on the grid. By extending discharge capability, the system is expected to reliably shift large volumes of renewable energy generated throughout the day, helping further reduce dependence on fossil-fuel generation, lower emissions, and support California’s long-term climate and reliability goals.
Ava Community Energy and CC Power were instrumental in advancing the project on an accelerated timeline. Both organizations represent CCAs that are deeply rooted in their communities and focused on delivering clean, reliable, and affordable power. Their leadership in bringing this project online ahead of regulatory deadlines highlights the growing role of local energy providers in driving innovation. “As a not-for-profit public agency, we’re committed to providing cleaner energy at competitive rates to the communities in Alameda and San Joaquin counties that we serve,” said Howard Chang, CEO of Ava Community Energy. “Long-duration storage projects like Tumbleweed are critical to delivering on that commitment. Our partnership with REV on this eight-hour battery helps us strengthen grid reliability and accelerate California’s clean energy transition.”
“The Tumbleweed project is a landmark achievement for California’s clean energy transition and the first eight-hour battery energy storage system in CAISO,” said Ed Sondey, CEO of REV Renewables. “It reflects REV’s leadership in developing innovative storage solutions at scale and marks another important milestone as we continue to grow our business and support a more reliable, resilient grid. We are grateful for the partnership and collaboration of Ava Community Energy and CC Power, whose shared commitment and vision were instrumental in bringing this groundbreaking project to fruition.”
Alexander Morris, general manager of CC Power, said, “We’re pleased to have partnered with REV Renewables and have been impressed with their successful development of this innovative project. The Tumbleweed long-duration storage project represents CC Power’s first operational resource and serves as an example of the innovative and emerging technology resources that CC Power was formed to procure on behalf of its members. We are excited about this milestone moment for California, what it says about the role of CCAs in proactively advancing the state’s goals for clean, reliable energy, and how joint action through CC Power can be a valuable tool to achieve those goals.”
—This content was contributed by REV Renewables.
