US large-scale battery power capacity grew by 35% in 2020 and has tripled in the last five years, according to the US Energy Information Administration (EIA).
Large-scale battery storage
The EIA notes the difference between battery power capacity and energy capacity:
The terms power capacity and energy capacity describe different energy measurements. Energy capacity is the total amount of energy the battery system can store. Power capacity is the maximum amount of power the battery can discharge at a given moment. Battery storage systems are usually designed to maximize either their power or energy capacity, depending on the battery’s intended use.
In 2020, year-end US battery power capacity reached 1,650 megawatts (MW). US utilities have reported plans to install more than 10,000 MW of additional large-scale battery power capacity from 2021 to 2023. That’s 10 times the capacity in 2019.
Five states account for more than 70% of US battery storage power capacity as of December 2020. California is No. 1 by a long shot at 31% (506 MW), followed by Texas, Illinois, Massachusetts, and Hawaii, which each have more than 50 MW of power capacity.
Large-scale US battery system energy capacity also continued to increase, reaching 1,688 megawatt hours at the end of 2019, a 30% increase from 2018.
Battery storage and solar
Much of the recent increase in new storage capacity comes from battery energy systems paired with solar. As of December 2020, 30% of large-scale battery storage systems were co-located with clean energy such as wind or solar, and 8% were co-located with fossil-fuel generators. The EIA notes:
We expect the relationship between solar energy and battery storage to change in the United States over the next three years because most planned upcoming projects will be co-located with generation, in particular with solar facilities. If all currently announced projects from 2021 to 2023 become operational, then the share of US battery storage that is co-located with generation would increase from 30% to 60%.
Photo: Kauai Island Utility Cooperative
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