The zinc-air hybrid flow battery, developed by the Canadian company Zinc8, is a new type of battery coming onto the market that can store several days worth of energy, is up to five times cheaper than lithium-ion, doesn’t degrade, and can’t possibly explode. Zinc8 is confident its technology could rattle the entire energy-storage market – replacing the need for transmission grid upgrades and making solar, and wind farms baseload.
Chief executive Ron MacDonald told Recharge:
Our market is eight hours [of storage] and above. And the reason is that as you increase your storage capacity — the overall cost of the system continues to go down very significantly.
Zinc-air is cheaper than lithium-ion because the system’s storage capacity can be made more prominent by increasing the size of the storage tank. With lithium-ion, you can’t do that. In other words, if you want 8 hours’ worth of energy, you’ll need two lithium-ion batteries but only one Zinc-air battery.
And since the potassium electrolyte is exceptionally stable, doesn’t get hot, and can’t ignite, some of the additional safety requirements of lithium-ion plants are unnecessary for zinc-air facilities, further reducing system costs.
How The Zinc-Air Hybrid Flow Battery Works
- It uses electricity from the grid to split the chemical zincate (ZnOH4) into zinc, oxygen, and water.
- The charged zinc particles generated can store electricity for weeks.
- When electricity is needed, the zinc is combined with oxygen and water (producing zincate) to release the stored energy.
The battery is made up of three parts:
- The “zinc regenerator” where the splitting occurs and the charged zinc particles are generated.
- The storage tank where the charged zinc is held in a potassium hydroxide (KOH) electrolyte.
- The power stack (a kind of fuel cell) where the zinc is turned back into zincate, and the charge gets sent back to the grid.
More Of A Baldies
Zinc8’s batteries are being compared to lithium-ion batteries, but the company’s market competition isn’t precisely electrochemical batteries. Its zinc-batteries would be more suitably placed in the intermittent energy storage (Baldies) technologies category.
Baldies include build-anywhere long-duration systems like liquid-air and hot-rock thermal storage – both of which can also store days’ worth of energy. An excellent example of the latter is Siemens Gamesa’s hot-rock thermal system at the commercial-scale pilot project in Hamburg.
Zinc8 won the New York Power Authority’s (NYPA) Innovation Challenge and is now collaborating on building a 100kW/1MWh (i.e., ten-hour) pilot project for a commercial NYPA customer in New York by 2022. NYPA is the largest state utility in the US. This project will showcase its battery’s long-lasting ability and serve as validation for future projects with the company.
A couple of other commercial pilot projects Zinc8 is working on include a 100kW/1.5MWh (15-hour) zinc-air system in Brooklyn for clean-energy developer Digital Energy and a 40kW installment in Surrey, British Columbia, Canada.