Electric Energy Storage Breakthrough?

This is really intriguing -- a fairly low-tech, low-loss way to store and smooth out power from intermittent sources (solar, wind), and one that works where there's no water or elevation gradient! If this pans out, this is great news, as it means that we can suffer less discomfort when we turn off the coal plants, as we must if we want any chance to bequeath future generations a stable climate.