Energy stored in batteries is being dispatched in large volumes in California as record-breaking hot weather in the Western US has brought the state’s electricity sector into crisis.
The California Independent System Operator (CAISO), which manages the grid and oversees electricity wholesale markets for more than 80% of California, has been issuing ‘Flex Alerts’ since August.
CAISO activates the alerts to manage the shortfall of electricity supply versus demand, asking customers to turn down their power usage and bringing as many resources as it can to ramp up supply.
For example, in Mid-August, a Flex Alert signified the first time that a network of 2,500 Tesla Powerwalls, aggregated into a virtual power plant (VPP) in the service territory of California investor-owned utility (IOU) Pacific Gas and Electric (PG&E), delivered up to 16.5MW of stored solar energy to the grid.
While in 2020, utilities enacted rolling blackouts in some areas to protect the grid and last year’s summer period also saw Flex Alerts activated, no one has been under any illusion that margins could continue to be tight. State Governor Gavin Newsom made moves to expedite battery storage deployment through cutting red tape as a State of Emergency was declared last year.
CAISO had said prior to the summer that it expected to have 4GW of battery storage capacity available, mostly from grid-scale, four-hour duration battery energy storage systems (BESS), it hasn’t quite made it that far. However, it is thought to be close to that mark, especially with a few big systems coming online in the past few weeks, like a pair of projects from AES Corporation totaling 227MW/908MWh.