California’s power grid has taken a significant step forward with the activation of Tumbleweed, the nation’s first major battery installation capable of delivering eight hours of continuous energy. This new system helps address the timing gap between solar generation and evening demand, paving the way for cleaner, more reliable electricity.
- Tumbleweed battery offers eight hours of energy storage
- Built by Rev Renewables using proven lithium-ion technology
- Supports cleaner electricity use late into the night
What happened
On June 1, the Tumbleweed battery facility in Kern County began operations as the first large-scale grid battery in the United States capable of discharging power for eight hours nonstop. This 125-megawatt installation is unique in its duration capacity since most existing batteries max out at four hours due to previous economic and market considerations.
Developed by Rev Renewables, the facility initially started with four-hour capacity in 2024, then expanded by doubling the number of battery units to achieve the current eight-hour run time. The battery uses well-established lithium-ion phosphate cells from BYD, showing that longer duration storage can be realized with proven technology.
Why it feels good
Tumbleweed addresses a critical challenge for California’s energy grid: solar power generation peaks during daylight hours, but consumer demand often spikes later in the evening. With an eight-hour battery, solar energy can be stored efficiently and discharged when energy use is highest, reducing reliance on fossil fuels and improving grid reliability.
Longer duration storage has been identified as a key factor in achieving near round-the-clock clean energy. California’s regulators, recognizing this, required utilities to procure extended storage systems. This project provides a model showing that lithium-ion technology can meet these needs and continue to improve in cost and performance.
What to enjoy or watch next
As Tumbleweed comes online, California Community Power and Ava Community Energy are working to optimize battery use within wholesale markets, preparing to maximize their share of the facility’s capacity. Real-world grid performance data from this project will guide future investments and operational strategies for long-duration storage across other regions.
Looking ahead, successful integration of eight-hour batteries can significantly reduce California’s dependence on less clean energy sources overnight and during early morning hours. If adoption expands, this technology could serve as a blueprint for other states aiming to increase renewable energy use and carbon-free electricity availability.