This containerized vanadium-flow storage battery in Snohomish, Washington, can supply power to 1,000 homes for eight hours. (UET)
It’s too big to fit in your mobile phone or electric car, but it’s the right size for the power grid. The vanadium-flow battery — V-flow for short — could lower your electric bill by offering larger energy-storage capacity of higher-powered electricity from renewable energy resources like solar and wind.
V-flow batteries are safe and noncombustible and last 20 or more years without deterioration, so they are prime competitors with lithium-ion batteries that can catch fire and explode, are expensive to make, and have shorter life spans.
Flow batteries employ two connected containers of chemical liquids that flow past a membrane to create a charge. “This type of battery can offer almost unlimited energy capacity simply by using larger electrolyte-storage tanks,” writes James Conca in Forbes. He adds, “The new V-flow batteries reduce the cost of storage to about 5¢/kWh.”
Of several U.S. companies making V-flow batteries today, UniEnergy Technologies (UET) has deployed the two largest-capacity systems in the world, according to the company — including a 2 megawatt/8 megawatt-hour system at the Snohomish County Public Utility District and a 1 megawatt/3.2 megawatt-hour system for Avista Utilities, both in Washington. Other installations are on order — a 100 kilowatt/500 kilowatt-hour V-flow battery system for the Las Positas College microgrid in Livermore, California, is one of them. A much larger 200 megawatt/800 megawatt-hour system is being built in China by UET’s partner company Rongke — enough to power several thousand homes.
Seamless integration of renewable energy into the grid is the watchword. That’s the focus of venture-capital-backed startup Avalon Battery, as described by co-founder Matt Harper in a post on the company’s LinkedIn page. Avalon is collaborating on an integrated system of NEXTracker solar trackers with V-flow battery storage.
And there are other battery and nonbattery storage technologies in the works. Stay tuned.
By: Lea Terhune