Batteries smash more records as they shift solar to evening peak in one of world’s biggest grids

The records continue to tumble in California, one of the world’s biggest state grids, with battery storage playing an increasingly dominant role soaking up solar in the middle of the day and shifting it to the evening peak, where it is now regularly the biggest single supplier.

The stunning new dynamics of the California grid have been emerging rapidly this northern spring, where renewable energy records are also tumbling, reaching a new peak of 158 per cent of demand on Saturday, and providing enough power to meet all local demand for up to nine hours a day, or more.

The excess supply of solar in the middle of the day, and negative wholesale prices, has prompted big batteries to soak up as much as they can in the middle of the day – sometimes accounting for up to 31 per cent of all load – and then injecting it back into the grid, where it accounts for up to 29 per cent of all supply.

According to data collected by Grid Status, new records were posted on the weekend for both charging and discharging for battery storage, with a record discharge of 6,523 MW on Saturday, and the record 31 per cent share of load earlier in the day.

Battery storage was once again the biggest supplier in the grid in the evening peak, ruling the roost from 7.10pm to 9.45pm on Saturday, and again from 7.10pm to after 9.30pm on Sunday.

The California government announced three days ago that new connections had taken the installed battery capacity in the state to more than 10 gigawatts (with varying amounts of storage), and at least another 5 GW is being built this year, much of it with four hours of storage.

The share of battery storage is unrivalled in the world, but could soon be challenged by the state of Western Australia, which like California has a high percentage of rooftop solar and fossil fuel generators that have or will exit the grid.

In W.A., most of the remaining coal fired generators are expected to close within a few years, and more than 1500 MW and 5,000 MWh of new capacity has been contracted with the specific task of time shifting rooftop solar from the middle of the day to the evening peak.

When those contracts take effect, from late 2025, the share of battery storage in the evening peak in Western Australia’s main grid is likely to be even higher than that currently seen in California.

For more on the W.A. story, see: Neoen’s Collie battery to be Australia’s biggest after winning new contract to flatten solar duck