On June 1, the Tumbleweed project in California’s Kern County became the first major battery installation in the U.S. that can discharge power for up to eight hours at a time — twice as long as typical energy-storage facilities.
The U.S. power sector now builds more battery storage capacity than any other form of on-demand power, like gas, nuclear, or geothermal. But battery developers typically design their projects to discharge at maximum capacity for four hours before running out of juice; that’s what has made sense, so far, given equipment costs and market opportunities. Analysts have concluded that longer-duration storage is needed to cost effectively power the grid with clean energy 24/7.
Consequently, California regulators in 2021 ordered power companies to procure longer-duration storage as part of the state’s planned transition to zero-carbon energy. California Community Power, a consortium of local nonprofit power providers, issued a contract for Tumbleweed back in 2022 to fulfill this obligation…