A wastewater treatment plant located in the Napa Valley of California, US is reportedly trialling a new energy storage system to help balance its energy demand and supply.

The Napa Sanitation District will trial a $3.2 million Tesla battery storage facility supported with a $1.9 million grant from utility Pacific Gas and Electric (PG&E). Energy cost reductions estimated at $110,000 annually will be split between Tesla and the district.

Tesla’s lithium ion batteries will be used to store energy produced by the district’s cogeneration plant at low cost periods, releasing it during peak price periods to support on-site operations.

‘Ultimately, it saves us money, we’ll be storing self-produced energy to be used during peak energy times,’ said Napa Sanitation General Manager Tim Healy.

The system has a 2 MWh storage capacity.