Hawaii has a problem, one that the whole world is likely to face in the next 10 years. And the solution could be a metal that you've probably never heard of - vanadium.
Whats vanadium? we have it in Drill bits and the tips of saws...
Hawaii's problem is too much sunshine - or rather, too much solar power feeding into its electricity grid.
Generating electricity in the remote US state has always been painful. With no fossil fuel deposits of its own, it has to get oil and coal shipped half-way across the Pacific.
That makes electricity in Hawaii very, very expensive - more than three times the US average - and it is the reason why 10% and counting of the islands' residents have decided to stick solar panels on their roof.
The problem is that all this new sun-powered electricity is coming at the wrong place and at the wrong time of day.
Hawaii's electricity monopoly, Heco, fears parts of the grid could become dangerously swamped by a glut of mid-day power, and so last year it began refusing to hook up the newly-purchased panels of residents in some areas. (see the Blog on Wind farms in Scotland - this could help too)
The amount of solar that's coming on-stream is just truly remarkable, but it all hits the system between noon and 4pm.
That does not marry well with peak demand for electricity, which generally comes in the late afternoon and evening, when everyone travels home, turns on the lights, heating or air conditioning, boils the kettle, bungs dinner in the microwave, and so on.
Solution - storing the energy for a few hours every afternoon until it is needed.
Vanadium's alloying properties have been known about for well over a century. Henry Ford used it in 1908 to make the body of his Model T stronger and lighter.
Today, vanadium mainly goes into structural steel, such as in bridges and the "rebar" used to reinforce concrete.
It is a small and sometimes volatile market. Supply is dominated by China, Russia and South Africa, where the metal is extracted mostly as a useful by-product from iron ore slag and other mining processes.
and NOW to the point Vanadium is the basis of a very, very stable battery.
Vanadium "redox flow" batteries are indeed stable. They can be discharged and recharged 20,000 times without much loss of performance, and are thought to last decades (they have not been around long enough for this to have been demonstrated in practice).