Today, SDG&E is showcasing the world's largest lithium-ion battery energy storage facility in partnership with AES Energy Storage, which will enhance regional energy reliability while maximizing renewable energy use. The 30 megawatt (MW) energy storage facility is capable of storing up to 120 megawatt hours of energy, the energy equivalent of serving 20,000 customers for four hours. 
Last year, the California Public Utility Commission (CPUC) directed Southern California investor-owned electric utilities to fast-track additional energy storage options to enhance regional energy reliability. In response, SDG&E expedited ongoing negotiations and contracted with AES Energy Storage to build two projects for a total of 37.5 MW of lithium ion battery energy storage. In addition to the 30 MW facility built in Escondido, Calif., a smaller 7.5 MW installation was built in El Cajon.   Full Press Release: