Utility-scale battery storage units, which are those with at least 1 megawatt of power capacity, are a newer electric power resource, and their use has risen recently. The operating capacity of these units has more than quadrupled to 899 megawatts in March 2019, from 214 megawatts at the end of 2014, according to the U.S. Energy Information Administration (EIA). Utility-scale battery storage looks to exceed 2,500 megawatts by 2023, if no existing operating capacity is retired and planned additions are completed.
Electricity utility Entergy Arkansas recently announced it would include 30 megawatt-hours of battery storage as part of its 100-megawatt solar power plant in White County near Searcy. It will be the largest utility-owned solar facility in the state and should be completed in 2021. Also, electricity utility Ozarks Electric Cooperative, Today’s Power Inc. and the city of Fayetteville are completing a 10-megawatt solar facility that will include 24 megawatt-hours of battery storage. It will be the largest solar facility on city-owned land in Arkansas and is expected to start operating by July 19.
The rise in the number of utility-scale battery storage units can be attributed to state energy storage policies that support them as well as an order of Federal Energy Regulatory Commission that directs power system operators to allow utility-scale battery systems to be part of their wholesale energy, capacity and ancillary services markets, according to the EIA. Also, the pairing of utility-scale battery storage units to intermittent renewable resources, including wind and solar, has become more competitive compared with traditional power generating options.
The two largest utility-scale battery storage sites in the United States as of March each provide 40 megawatts of power capacity, including the Golden Valley Electric Association’s battery energy storage system in Alaska and the Vista Energy storage system in California. In the United States, 16 battery storage sites are operating with an installed power capacity of at least 20 megawatts. California, Illinois and Texas account for nearly half of the 899 megawatts of installed capacity.
In the first quarter of 2019, 60 megawatts of the installed capacity started operating. By the end of the year, 108 megawatts of additional capacity is expected to start operating. The largest is expected to be the Top Gun Energy Storage facility in California with 30 megawatts of installed capacity.
From March through 2023, utility-scale battery storage capacity is expected to nearly triple, increasing by 1,623 megawatts. Of that amount, two projects account for 725 megawatts and are expected to start operating in 2021. The largest is the Manatee Solar Energy Center in Parrish, Fla., and will have a capacity of 409 megawatts, making it the largest solar-powered battery system in the world and will store energy from a nearby Florida Power and Light solar plant in Manatee County. The second-largest battery storage unit will be the Helix Ravenswood facility in Queens, N.Y., and it will have a total capacity of 316 megawatts.