Are Vanadium Flow Batteries The Solution To 'Too Much' Solar Power?

It's a statement of the obvious, but solar panels do their best work during the day, specifically noon and early afternoon when the sun is at its strongest.

The trouble is, this rarely tallies with when energy use is at its highest--typically in the evening, when everyone gets home from work.

The solution to bridging this offset supply and demand is energy storage, and the metal vanadium could be instrumental in our future storage needs.

Vanadium's unique properties make it highly useful for developing stable batteries--ones that can be charged thousands of times without suffering degradation or capacity loss.

As the BBC reports, vanadium can lose or gain electrons very easily.

This is demonstrated using a chemistry experiment in which oxidized vanadium in sulfuric acid--vanadium stripped of its five outermost electrons--turns from a yellow solution through green, blue and violet in the presence of zinc. The color change represents electrons being passed to the vanadium.

This same process can be demonstrated on a much larger scale, in a battery.

Called a Vanadium Redox Flow Battery, it consists of two tanks of different solutions of vanadium separated by a membrane.

As fluid is pumped past electrodes on either side of the battery, current is produced. Electrons are released by one side and received by the other--changing the color of the solution as they do so. And these electrons generate the current.

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The battery chemistry, of course, doesn't really affect the job the battery does--the aim here is to store solar energy during the day. You could do this with a lithium-ion battery--indeed, old lithium batteries from electric vehicles are often used in such a manner.

It's the vanadium battery's long life that makes it useful here.