Lithium-ion versus flow batteries, versus the future

As the energy storage industry begins to see meaningful growth in markets around the world, all eyes are on lithium-ion technology. But developers and utilities are investigating other battery concepts. Flow batteries are seen by some as having particularly strong advantages over lithium-ion, and several large-scale batteries are already being built using this technology.


The world’s largest single-axis tracker manufacturer – and aspiring solar power plant developer – Nextracker, has also heard the call of the flow battery and is installing them. The NX Flow is a 10 kW-AC / 40 kW-DC vanadium flow battery.

The batteries are delivered ‘wet’ – meaning you plug them in and they run, since they were assembled in a factory. These batteries sit at the end of a 30 kW-DC, 1,000-V string of solar modules, allowing for pure and efficient DC-coupled battery charging.

Nextracker Chief Technology Officer Alex Au said, “During our evaluations of more than 40 storage alternatives, we looked at many variations on lithium-ion to flywheel to flow, as well as a host of software providers. We set our targets aggressively high by looking for a solution that was free of limitations prevalent with many technologies. Limitations characterized by mindsets like “can you use it and how much are you allowed to use it” and quantifying “are you using it in such a way that you’re keeping the product stable, so that it can be used for a long time.”

And if you give Nextracker just a moment, they’re going to tell you that with the NX Flow, what we’re really seeing are the building blocks of the world’s future solar power plants. Au says it’s time that the solar industry started to think about delivering stable, dispatchable solar powered power plants – not just solar farms – to the power grid. Not a bad start for flow batteries…

Read more from pv magazine here.