The engineering firm hopes a storage system can smooth electricity supply on a grid powered by renewables—and let it capitalize on a fast-growing market.

The news: GE announced a new system called Reservoir—a large battery attached to the grid to store spare electricity from renewables. When the sun doesn’t shine and wind doesn’t blow, it dumps electrons into the grid to meet demand. It uses discharging smarts to extend its working life, and it’s modular, so it can be adapted to fit small or large gigs.

Electric potential: Grid storage is growing—fast. The Energy Storage Association predicts that US storage in use will double over 2018. The Wall Street Journal notes that the market is predicted to be worth tens of billions of dollars in the next 10 years. GE, which is struggling financially, will hope Reservoir grabs it a slice of the pie.

But: There’s competition. Tesla has its own grid batteries that are deployed in South Australia as part of a huge 129-megawatt system. A Siemens venture called Fluence is building a system in California that will be three times as big. GE, meanwhile, has just a 20-megawatt commitment for Reservoir so far.