But encouraging as this is, it isn’t the full picture, because renewable energy is inherently intermittent, and we have yet to build the energy storage that can help keep the grids buzzing when the sun isn’t shining and the wind isn’t blowing. Batteries, excellent as they are, are not energy-dense enough to solve this conundrum. The likeliest backup, alongside a host of new hydroelectric reservoirs, is a brand new fuel: hydrogen.
