General Motors said it will take a $1.6 billion hit in earnings this quarter due to the slowdown in sales of electric vehicles, according to a filing with the SEC today. EV sales in the U.S. have fallen short of ambitious targets and the $7,500 federal tax credit expired at the end of September.

Other automakers have also scaled back EV goals after years of investment in domestic supply chains. It’s left some battery manufacturers in the U.S. with extra capacity that’s now helping to power up the market for grid storage.

Manufacturers are faced with a problem: They have a nice new battery supply chain all charged up, with not enough electric cars to power.

“If you stood up these factories, you want to keep them producing,” said Jay Whitacre, a professor of energy engineering and policy at Carnegie Mellon University.

He said battery producers and suppliers that were focused on cars can fairly easily switch to making batteries that hold electricity for the grid.

“They can use the same production line, typically, to make these cells,” Whitacre said.

Stationary batteries are needed to store renewable energy from wind and solar that’s generated intermittently. But they’re also increasingly in demand for data centers.

“They want these plants to be reliable, and so regardless of where the power is coming from, whether it's coming from renewables or coming from burning coal, they're all installing energy storage systems to provide backup power,” said Sam Abuelsamid, a market research analyst at Telemetry.

He pointed to EV battery maker LG which already converted one of its major U.S. production facilities to grid storage.

“And I wouldn't be surprised to see some other plants that have excess capacity follow a similar path,” said Abuelsamid.

Even The Battery Show, an annual convention held in Detroit last week, had a different flavor, according to Mickael Havel at the battery materials supplier Arkema. In the past, he said, car batteries were the belle of the ball.

“This year we saw, like energy storage used for data centers and AI, for sure, that was an emphasis,” Havel said.

Arkema sells specialized coatings and binders for lithium-ion batteries, whether they’re in cars or stationary.

“So, for us, we are kind of agnostic,” Havel said.

As long as someone is still buying batteries.