The number of wind farms in the U.K. has more than quadrupled since 2010. But last year, when a “wind drought” over more than a week meant that it was suddenly much less windy than usual, the country had to scramble to buy extra power made from fossil fuels.
It’s one example of renewable energy’s biggest challenge: When the sun isn’t shining and the wind isn’t blowing, the grid still needs a source of power. Lithium-ion batteries—like the giant batteries that Tesla has installed in Australia—can store the energy generated by renewables, but are too expensive for long-term storage.
To move completely away from fossil fuels, the grid needs a different solution. Form Energy, one startup working in that space, thinks that iron—which is cheap and abundant—is the key to building better batteries. The company’s “iron-air” batteries, which cost less than a tenth of lithium-ion batteries, can affordably store energy for days.
Dealing with intermittent renewable energy for a few hours, or overnight, isn’t as hard, Jaramillo says. But backing up that power for days, or even weeks, is much more difficult. When he left Tesla, he didn’t know what technology could solve the problem or whether it would be possible to quickly bring it to market.
The team considered multiple possibilities for the technology, building an analytic platform to compare the options in detail. “The problem that we were going after is a very large problem, and it’s a very large market,” he says. “So any option we were considering had to be able to scale to meet the size of the challenge—thousands of terawatt hours capability. And it also had to be safe. It had to be fundamentally cheap, fundamentally scalable, and fundamentally safe.”
The company’s first pilot, with a utility in Minnesota, will launch next year, with 1.5 megawatts of storage. Larger pilots will follow in 2024 “in the tens of megawatts scale, and then going from there, quickly, to the hundreds of megawatts scale,” Jaramillo says. The company, which now has around 200 employees, will be scaling up from R&D to large-scale manufacturing, and is working on detailed studies to prove to financing companies how the technology performs and how durable it should be, so it can get very low-cost capital to build it. “We’re developing infrastructure,” he says. “And if you want to deploy a lot of infrastructure, you have to be able to finance it like infrastructure.”