As we transition to a green economy, we’re generating waste that, if we aren’t careful, isn’t so green. We looked at barriers and opportunities around three of the most challenging types of clean energy tech waste. This is one story in that four-part series.
Read the introduction here: What happens to old EV batteries, solar panels and wind turbines?
Read part two here: Here’s what happens to solar panels when they’re retired
Read part three here: Old wind turbine blades get new spin, as businesses turn problem into opportunity
The field of solar panels dotting a stretch of desert in Lancaster looks like a typical solar farm. But the project, owned by Santa Monica-based B2U Storage Solutions, is believed to be the nation’s first to pair a solar energy system with retired EV batteries, which store the energy captured by solar panels and sell it back to the state energy grid as needed.
Batteries for EVs are the green tech waste stream that gets the most attention. But experts say they might be the least problematic, with many examples of profitable repurposing and recycling operations already established.
While EV sales hit a record high in 2023, just 1% of the nearly 300 million vehicles in the United States today are electric. And since battery warranties typically run for eight to 10 years, Slattery said there just haven’t yet been many retired batteries to grapple with.
That will change soon, though, with consulting firm McKinsey & Company estimating more than 100 million EV batteries will be retired over the next decade.
The first preference, if possible, is to find a second life for retired EV batteries.

Many EV warranties kick in when a battery dips below 80% of its range capacity, according to Jessica Dunn, a senior analyst focused on transportation at the Union of Concerned Scientists. That means those batteries have lots of life left for energy storage, such as the Lancaster project. There are talks of using old batteries to charge existing EV batteries, Dunn said, or to supply electricity to grocery stores when the power goes out so they can avoid using gas-powered generators.
Reusing batteries in this way “is a relatively new concept that has yet to build a track record of performance” though, according to Jason Burwen, a vice president with Oregon-based GridStor. That’s why Burwen’s company is sticking with new batteries as it looks to develop a stationary storage facility in Santa Fe Springs.
To build confidence in second-life options for EV batteries, Meg Slattery, a PhD candidate at UC Davis who’s been studying battery recycling, said there needs to be better data sharing about the life of the equipment and tools to measure their health.