What is a flow battery system?

A flow battery system, designed to stockpile massive amounts of energy, at a plant on Hokkaido. If the world is going to power itself with renewable energy, it needs to be ready at a moment’s notice.

How much energy will a flow battery store?

The battery will store 800 megawatt-hours of energy, enough to power thousands of homes. The market for flow batteries—led by vanadium cells and zinc-bromine, another variety—could grow to nearly $1 billion annually over the next 5 years, according to the market research firm MarketsandMarkets.

Where do flow batteries come from?

China and Russia dominate the market for vanadium, the metal that makes flow batteries durable and easy to maintain. “The supply chain for vanadium is extremely precarious,” said Kara Rodby, a battery analyst at the investment firm Volta Energy Technologies. Still, flow batteries are making their debut in big real-world projects.

How do flow batteries work?

That's where flow batteries come in. They store electrical charge in tanks of liquid electrolyte that is pumped through electrodes to extract the electrons; the spent electrolyte returns to the tank.

How long do flow batteries last?

“There really is no finite lifetime for a flow battery in the way there is for lithium-ion,” Rodby said. Sumitomo Electric President Osamu Inoue said his company guarantees its flow batteries will last 20 years — but the vanadium inside can be reused forever in future batteries.

Are flow batteries finally about to take off?

“It looks like flow batteries are finally about to take off with interest from China,” said Michael Taylor, an energy analyst at the International Renewable Energy Agency, an international group that studies and promotes green energy.