Battery storage is powering up in the United States. PJM and CAISO accounted for the maximum number of battery storage installations between 2010 and 2018. The cycles turned towards other jurisdictions that year. More than 58% of new battery storage additions were made in jurisdictions outside of PJM and CAISO after 2018, according to the EIA.
The average costs per unit of energy capacity have also declined, from 61% between 2015 and 2017 to $834/kWh in . "The large decrease in cost makes battery storage more economical, helping accelerate capacity growth," writes the EIA. Of course, this figure does not compare well with the economics of existing sources, whether it is fossil fuel or nuclear or, even, renewable energy like solar and wind.
However, such equivalencies run the risk of an apples-to-oranges comparison. Battery storage has a different use case and performs a different function in the grid as compared to traditional, always available sources of energy from the grid. Recent grid outages and malfunctions coupled with regulation favoring renewable energy sources are creating a use case for storage at facilities and residential buildings where electric supply is critical or can be afforded. The Wall Street Journal recently reported on data centers deploying large batteries, in conjunction with renewable energy sources, to keep the lights on. Research firm Guidehouse Insights estimates that businesses will deploy 220 MW of battery storage in the coming year, up from 77 MW this year.