Popular Science reports that the US Department of Energy is "providing a nearly $400 million loan to a startup aiming to build a zinc-based alternative to rechargeable lithium batteries."
If realized, its industrial-scale zinc-bromine battery energy storage system Eos Energy could provide cheaper, much more sustainable options for the country's growing renewable energy infrastructure. In contrast to the lithium-ion batteries and lithium iron phosphate, alternatives such as the Eos design use zinc-based cathodes alongside a water-based electrolyte such as reports the MIT Technology Review. This important distinction both increases their stability, and makes it incredibly difficult to catch fire.
Meanwhile, zinc-bromine batteries have a lifespan of up to 20 years, while existing lithium batteries last 10 to 15 years. In addition, zinc is the fourth most produced metal in the world.
The US Department of Energy says that "over time", Eos expects to source almost all of its materials within the US, better insulating its product against market volatility and supply chain issues.
The MIT article states that Eos' semi-autonomous facility in Pennsylvania already produces about 540 megawatt-hours per year — and it's not running at full capacity. The new loan could push the plant toward full capacity. The $398 million loan finances “up to four state-of-the-art production lines,” according to the announcement of the US Department of Energy.
If completed, the project is expected to produce 8 GWh of storage capacity annually by 2026. That's enough to power over 300.000 average US homes instantaneously, or meet the annual electricity needs of about 130.000 homes if fully charged and are discharged daily.
It should be mentioned that Eos batteries are non-flammable and do not require active cooling to function. They can achieve 100% depth of discharge.