Work has been completed on the largest battery energy storage system (BESS) to have been paired with solar PV to date, with utility Florida Power & Light (FPL) holding a ceremony earlier this week.

Construction on the Manatee Energy Storage Center in Florida’s Manatee County was completed in just 10 months, having begun in February this year. The 409MW / 900MWh BESS is colocated with FPL’s existing 74.5MW Manatee Solar Energy Center ground-mounted PV plant.

Allowing solar energy to be used in evenings and at night or on cloudy days, the utility company — a subsidiary of electric utility holding company NextEra Energy — has placed 132 battery containers onto a 40-acre plot of land.

The BESS will charge at off-peak times with abundant solar energy and then discharge to the local grid at peak times, when power is most expensive and often at its most carbon intensive.

It will reduce the runtime of local fossil fuel power plants and will aid FPL in a plan to ease two 1970s-era natural gas power plants totalling more than 1,600MWh into retirement.