NineDot Energy raises big money for small batteries in New York City

Startup NineDot Energy just raised $431 million to build batteries in New York City’s vacant nooks and crannies — an endeavor that will help the metropolis fend off looming electricity shortages.

The debt financing announced Monday will support the Brooklyn firm’s plan to develop 28 battery projects totaling 494 megawatt-hours of energy storage capacity over the next two years. NineDot estimates that’s enough storage to meet the peak energy needs of about 100,000 households.

NineDot is one of several companies deploying ​“community battery systems” — grid-tied energy storage installations that can fit into roughly an acre of land or less — in New York City. These systems sop up excess energy from the grid when power is abundant and send it back when demand is high, like on hot summer afternoons when millions of air conditioners crank up. Bigger batteries may be able to store more energy, but community-scale systems can be more realistic to quickly deploy in über-dense places.

New York law sets a statewide goal of 70% renewable electricity by 2030, and state policy calls for building 6 gigawatts of energy storage by 2030. Upstate New York has plenty of land for utility-scale wind, solar, and battery farms. But downstate New York and New York City are where power demand is greatest and the generation mix is the dirtiest — and there’s not yet enough transmission grid capacity to solve those problems with clean power from the north, Cohen said.