Duration of utility-scale batteries depends on how they’re used

https://www.eia.gov/todayinenergy/detail.php?id=51798

"Battery operators report that more than 40% of the battery storage energy capacity could perform both grid services and electricity load shifting applications. About 40% performed only electricity load shifting, and about 20% performed only grid services. Batteries with a duration of less than two hours are considered short-duration batteries... Batteries providing grid services discharge power for short periods of time, sometimes even for only seconds or minutes economical to deploy short-duration batteries"