Energy security

Four maps show how electricity generation has changed in the US

The second map takes a look at the predominant form of renewable energy in each state in 2007 and in 2017. Here, we really see the growth of solar. In 2007, solar was the most-used renewable energy source in zero states, but by 2017, it had replaced biomass or hydro in seven states. Wind grew even more than solar over that decade, going from the predominant renewable source of electricity in seven states to the leader in 16 states.

Interestingly, hydro's share of the renewable energy landscape played out a lot like coal's over the past decade: hydro went from the most prevalent renewable resource in 28 states down to 19. But that's not because hydro plants are getting retired—rather, hydro is losing ground to other energy sources because so much solar and wind power are coming online.

"In Maine and Vermont, the share of electricity generated by biomass trails only hydroelectricity, making them two of only three states where renewable fuels provided both of the top two generation shares," the EIA wrote. "South Dakota, where hydroelectricity and wind were the most prevalent sources, is the third state."