California batteries dominate evening grid with 10 GW/40 GWh of capacity

California announced that they’ve crossed the line of having 10 GW of energy storage installed on its power grid. As of the announcement, the state had noted that exactly 10.379 gigawatts of output was connected, which was an increase from 770 megawatts that was connected in 2019.

The state projects that it’ll need 52 GW of batteries connected to its grid by 2045. Along with an additional 57.5 GW of solar, state models suggest an additional 15.7 GW of four hour lithium ion batteries, and 19.5 GW of eight hour lithium ion batteries. Additional pumped hydro and long duration energy storage are also considered, however, in the models the volumes projected for now are low.

While the press release, and generally available public data, does not release data on the amount of hours that these systems would output, one can roughly estimate the hours based upon state standards, and general industry hardware standards.

The state has installed 154,155 total energy storage systems as of April 15th. Of those, just over 98% are residential systems totaling 1.076 GW of output capacity. Of the remaining, 2,777 are commercial systems, while 175 are directly grid connected utility scale facilities.

For the residential and commercial systems, totaling 1.647 GW, the general industry standard is to install from two to four hours of storage capacity behind the output capacity. If we estimate an average of three hours per output megawatt, then 4.951 GWh of storage may be available behind these units.

In California, because of policy, most utility scale batteries are four hours – suggesting the state’s 8.736 GW of out capacity has 34.944 GWh of storage behind them.

In total, 39,895 GWh of energy storage was connected to the grid as of a couple of weeks ago.

More significant than the capacity value though, is what the batteries are doing.

In 2019, California knew it had a challenge: fossils were retiring & evening peak periods were power failure prone. The state saw a need for <4.7 GW of power to handle these periods by 2022, and so implemented plans to deploy energy storage plus additional solar to fill up these batteries.

This spring, we’ve seen batteries do exactly what they were design to do – take over the evening peak periods.

For instance, on April 27th at 8.40 PM PST, utility scale batteries were outputting over 6.5 GW of power – the largest source of electricity by far. There were multiple hours when the batteries were the largest source as well.

An additional 8 GW of energy storage is expected to be deployed in the next year.