Callisto I is a 200 MW/400 MWh battery energy storage system located in central Houston, ten miles from the Houston Ship Channel at the site of a former HL&P H.O. Clarke fossil-fired power plant.

The site can accommodate an additional 400 MW/800 MWh of battery energy storage generation, Jupiter Power officials said.

Jupiter Power is a developer, owner and operator of standalone, grid-connected battery storage projects. Callisto I is Jupiter’s ninth project in ERCOT, bringing its total ERCOT fleet to 1,375 MWh. In December of 2023, Jupiter Power announced the closing of a $65.2 million financing with First Citizens Bank to finance the construction of Callisto I.  

Jupiter Power said Callisto I significantly increases Houston’s supply of reliable, zero emissions power as it faces record demand increases. This growth and recent extreme weather events in Texas has led to efforts by state lawmakers to incentivize adding more dispatchable power to the ERCOT grid.