On February 1, California’s batteries bridged the solar gap with seamless precision. After discharging all night until dawn, they spent the daylight hours charging, then resumed exporting energy until well after midnight, effectively allowing the state to run a full 24-hour cycle on solar power.
Technically, all batteries can be used as long-life batteries, and they can operate for twenty-four hours, as long as the output power is limited in relation to the stored energy. However, if some batteries work overnight, it means a little more.
On February 1, the batteries gave out just a little more Independent system operator from California (CAISO) electricity grid region. CAISO, which supplies 80% of the state’s electricity needs, never stopped powering the grid with batteries, staying on until the sun rose. Moreover, because the batteries are usually charged cheaply, would have been shortened – solar energy, it is fair to say that sunlight at least partially powered the state for over 24 hours.
Image: CAISO supply trend chart as of February 1, 2026
The large green swath represents the renewable energy sources, consisting mainly of solar energy, that take over California’s entire electricity needs during the day. During the day, the batteries (represented by the purple section diving deep into the ‘negative supply’ area of the map) charged from excess solar power until solar generation dropped around 4:15 p.m. Based on their signal, the batteries began powering the state again, exporting electricity until midnight until 12:30 the next day.
The state of California was powered to some extent directly by solar energy and indirectly by batteries, beginning at 4:05 a.m. on January 31 through 12:30 a.m. on February 2, for a total of 44 hours and 25 minutes continuously.
While technically none of the batteries followed the exact same charge/discharge schedule as the entire battery fleet, it is impossible to say that “one battery” powers the state all day. During the periods when we celebrated batteries being exported to the grid, batteries were probably also being charged.
California’s goals in deploying their battery fleet are to merge many energy sources, which will also soon be integrated New Mexican and eventually offshore wind energy – to wean the state off fossil fuels. These batteries in combination with such a huge solar initiative are accelerating the go-to-solar process.
Moreover, batteries become the largest source of electricity in the morning hours.
Image: CAISO supply trend chart
While batteries the largest source of electricity on the CAISO evening grid since the first half of 2024, this could be one of the first times they take over before the sun rises. The batteries are exported during this period due to higher prices, which are caused by people waking up and going to work and school before the sun sets, and instantaneous solar energy generation begins to increase.
From February 2 at 6:25 am, batteries took over the role of the main source of electricity for the grid. They remained the primary source for about an hour, before cutting out for the next hour and switching to charging at 8:20 am. On the same day, batteries were also almost the main source of electricity in the evening.
How long will it take for solar or batteries to be the No. 1 source of electricity for an entire day?
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