The article doesn't mention this, but I assume part of this is because the US is actively dismantling hydro power by removing dams. It turns out what while hydro power is "green" in terms of not polluting, it's still quite harmful to the environment because of animals like salmon that need to be able to traverse rivers and the rest of the ecosystem that depends on them.

https://en.wikipedia.org/wiki/List_of_dam_removals_in_the_Un...