Fossil fuels are the boogieman for many people. While they essentially power our entire way of life, they create pollution. We’ve mitigated a lot of that over the years, but now the problem are so-called greenhouse gases, and we need to put an end to
Hydro is fine, but almost all the good sites have already been taken. The ones remaining are quite marginal.
Unless, of course, you're in California or Washington, where they've been dismantling existing dams because environment.
Aside from that, it's nukes or nothing - and Our Superiors are quite clear it's going to be nothing.