Chemistries for stationary batteries gain steam

As demand for car batteries cools, companies developing technologies to store electricity in stationary batteries are attracting investor attention. These firms are developing alternatives to lithium-ion chemistries that they say will be better suited for the electrical grid and other stationary applications.

After snagging a $150 million US Department of Energy (DOE) grant in September, Form Energy has raised more than $400 million from private investors to accelerate manufacturing and initial deployment of its iron-air batteries. Earlier this year, ESS Tech announced it would expand production of its long-duration iron flow batteries, and Eos Energy Enterprises secured $316 million to fund commercialization of a zinc-based battery.

Electrical utilities use batteries to balance the supply of electricity with demand. Batteries can also provide backup power or store solar energy generated at midday for use in the evening.

Currently, the best option for these applications is usually a lithium-ion battery, says Allison Weis, the global head of storage for the consulting firm Wood Mackenzie. Lithium-ion battery systems can discharge electricity for up to a few hours at a time, but it’s expensive to use them to provide energy for longer than that.

As the amount of electricity generated by wind and solar increases, Weis says, batteries with other chemistries that can store energy for dozens of hours or days will become an important way to ensure that power is available continuously, even on cloudy or windless days.

“Long term, it’s going to be the 5 minute and longer energy swings and uncertainty in renewables that will drive the need for the amount of storage we have coming online,” she says.

ESS and Eos say their batteries can provide power for up to 12 h, and Form’s battery can supply energy for up to 100 h. Some customers are starting to test them. ESS has installed batteries at airports, universities, and other locations; Eos batteries have discharged about 3.6 GW h of electricity so far, and six utility companies plan to start using Form’s battery by 2026.

A 2023 DOE report concluded that long-duration batteries will be a key part of reducing emissions from electricity generation, but it noted that costs need to keep falling for the industry to be economically viable without government support.