> The reason? Their fundamentally unreliable nature. Both solar and wind produce too much energy when societies don’t need it, and not enough when they do.

> Solar and wind thus require that natural gas plants, hydro-electric dams, batteries or some other form of reliable power be ready at a moment’s notice to start churning out electricity when the wind stops blowing and the sun stops shining.

> And unreliability requires solar- and/or wind-heavy places like Germany, California and Denmark to pay neighboring nations or states to take their solar and wind energy when they are producing too much of it.