Well, uranium wins most efficient by weight - with an insanely huge margin. Of course the cost per kilowatt also knocks that right back down.

Fracking is pretty damn bad for the environment, and that’s the main extraction method here in PA. So that impact is a factor as well and should be included.

For industry we’ll need coal - it’s required to make coke which is then used to make steel. Using coal for energy is bad for the environment, but necessary for other things as a raw resource (like gold for computer chips).

Solar and wind are helpful and we should work towards them. But we do need a base load that can provide extra power when renewables can’t meet demands due to the weather.

Nuclear power is much safer and efficient now. Every significant accident was due to old technology. We’ve learned a lot from those that did happen and aren’t that dumb anymore.

Didn’t really write this out in any particular order. That said, all things considered my thoughts are we should be aiming for solar and wind as well as we can, and have nuclear as a base load. Ramp up the nuclear plants as needed to adjust for renewables if their capacity is lost temporarily. It’s the only long term solution I can see working. Good luck convincing the short sighted corporations and governments of the world that though.