Battery storage systems can meet a variety of electrical grid needs, from improving power quality to supporting local distribution circuits and capturing renewable energy for later use.

Southern California Edison demonstrated the versatility of the technology when three pilot battery storage systems were called to action in August as California experienced its first rotating outages in 19 years. After successfully providing electricity to customers during the August emergency, the systems were in place and ready to respond during the September heat waves.

“In addition to SCE taking immediate action to do everything possible to prevent further disruptions to customers and address the statewide emergency, we saw this as an opportunity to demonstrate the benefits energy storage can offer in support of resource adequacy,” said Juan Castaneda, SCE principal manager, Grid Technology Innovation, whose team oversees the three pilots. “Energy storage can provide real-time solutions.”

Before the August heat wave, the three systems were dedicated to a program piloting the use of storage to meet local needs for power quality, ease reliability issues and address reverse power flow. When customers are not using much electricity, excess power can overload the circuit and SCE can use battery energy storage systems to manage this reverse flow. These batteries can provide electricity for about 5,000 homes throughout the course of two hours.

“Batteries are incredibly flexible while being an environmentally friendly option to meet customer demands,” said Marci Palmstrom, SCE director of Trading & Market Operations.

The pilot projects — DESI 1 in Orange, DESI 2 in Santa Ana and Connolly in Lancaster — were charged and discharged during the August outages, supplying power when SCE customers needed the energy. Based on lessons learned, the pilots kept to their schedule of discharging for two hours each day.

When the temperatures rose in September, the pilots were already providing support to the grid, a strategy that aligns with “our goal of building pilot energy storage systems and evaluating the number of ways to use them to benefit our customers,” said Castaneda.

Peak energy demand is 3-9 p.m., when solar energy generation tapers off and temperatures remain high. The three systems were discharged for two hours starting around 5 p.m. on Aug. 15, when the outages took place, and on Aug. 17, to help avoid further outages. The systems continue to discharge each day starting around 5 p.m.

Other SCE battery storage facilities can also respond during an energy emergency and heat wave. In the days following the August and September heat waves, the timeframe for powering up SCE’s Mira Loma units 2 and 3 was increased during off-peak hours, enabling the batteries to provide additional supply to the grid. Mira Loma units 2 and 3, located in Ontario, can supply 80 megawatt-hours, enough to power 15,000 homes for four hours.

Operations at Mira Loma have returned to normal, however, SCE is “always looking at ways to maximize value and support the reliability of the grid and will adjust the batteries functionality based on the needs of the market,” said Palmstrom.

Another facility, the Hybrid Enhanced Gas Turbine system in Norwalk, a 10-megawatt battery storage system combined with the gas turbine, also provides flexibility to the grid. The fast-ramping, 24/7 systems allows the peaker plant to quickly respond to changing energy needs and can instantly step in when the sun or wind can no longer meet system needs.

SCE continues its leadership role in energy storage, recently signing seven contracts totaling 770 megawatts of battery-based energy storage resources to help enhance the region’s electric system reliability needs.

Using batteries during an energy emergency demonstrates their value in providing resilience to the grid to help withstand severe weather conditions due to climate change. In turn, they will offset the need to build new power generation stations to meet growing energy demand while expanding the capacity to run on renewable resources as more solar and wind come online.

These steps will help meet SCE’s Pathway 2045 plan, which aims to meet California’s goal for 100% carbon-free energy and 30GW of energy storage.