We need to store the huge quantities of excess electricity generated by variable renewables. But what’s the best way? Currently, over 99% of large-scale electricity storage uses pumped hydro dams. But geography severely limits where you can build one. And the growth of grid-scale batteries is limited by raw material costs and short lifecycles. Antoine Koen and Pau Farres Antunez at Cambridge University review an important alternative, Pumped … [Read more...]