This is one of a number of solutions being put forward to replace or complement lithium "big battery" installations designed to soak up excess energy when the grid's not using it, and then feed it back in when it's required.

We're going to need insane amounts of energy storage in the coming decades; within 30 years, we need to replace all the world's current 2.045 terawatts (that's 2,045,000 megawatts) of coal-fired electricity generation with clean alternatives, while significantly expanding that capacity to keep up with skyrocketing demand as nearly everything else that runs on fossil fuels – cars, trucks, boats, planes, industrial processes, you name it – gets electrified as well.

There's more than enough clean, renewable energy available; it just doesn't get generated right when it's needed the way coal-fired power can. So until the unlikely goal of a global energy grid is realized, the world's appetite for cheap ways to store and release green electricity is going to ramp up like mad.