First developed by NASA, flow batteries are a potential answer to storing solar – and wind – for eight to 10 hours, far beyond what is commonly achieved today with lithium-ion. In the first of a two-part special report, Andy Colthorpe learns what the flow battery industry faces in the fight for commercialisation.
Solar is easy to explain. Sunlight hits panels, electricity hits grid. Then come the inevitable questions about using power when the sun doesn’t hit the panels, about batteries and the well-rehearsed explanation comes that yes, while it would be great to use solar power 24/7, we’re just not there yet with the cost of technologies as they are, for the most part.
So the more complex explanation follows that lithium batteries are being deployed at large-scale to store energy for short periods of time, to deliver frequency regulation, or to remove specific hours of a peak demand period. A market need for long-duration storage remains elusive outside of specific circumstances such as remote grids where batteries and PV are replacing expensive diesel. Providers of flow batteries would beg to differ.
While acknowledging that lithium’s head start from a mass production perspective and other factors contribute to a higher capex overall for flow, flow energy storage providers are quick to point out the long lifetimes of their machines, the low cost of their raw materials, the comparative lack of fire hazard and associated balance-of-system costs and sheer ability to store huge amounts of energy, rather than power, mean flow could be the cost-effective long-duration choice of the renewables industry.
“People used to ask us what we needed the fifth hour for and now they ask if we can go to 10 hours,” Jorg Heinemann, chief commercial officer at Primus Power says.
Heinemann joined zinc bromine stationary energy storage maker Primus Power after eight years developing utility-scale PV with SunPower, believing long-duration storage to be the natural next step for renewable energy. Customers that have large amounts of solar PV are now approaching Primus with the intent to use solar-plus-storage as peaker replacements and to use behind-the-meter battery assets to offset transmission and distribution (T&D) investment costs.
“That’s beyond four hours [of storage], that means putting in a request for five, six or even eight hours, to take renewable power and add it to the storage and you’ve eliminated the need for a peaker. That last wave of use cases, T&D deferral, gas peaker replacement, heavy duty renewable extension,those are new, at least new to us. People have talked about them in theory, we’re now getting those active requests.
In California, where Primus is headquartered, lithium batteries have now been deployed to provide capacity in the wake of natural gas plant retirements and questions over security of supply following the Aliso Canyon gas leak, marking a milestone for batteries to be used on the grid for more than short-term balancing services. The state’s main investor-owned utilities now also have to include consideration of four-hour duration energy storage in their Resource Adequacy Plans. Other parts of the world are moving there faster, with various dispatchable solar projects announced in recent months.
Recent Comments