I really like the idea of pumped storage hydroelectric generation. I think it is a smart idea. The idea of chemical batteries is interesting but I wonder about the environmental cost of batteries versus pumped storage.
First, both are net consumers of power. There are costs associated with pumping water uphill and there are costs associated with losses in batteries. Batteries might come out ahead. However, I wonder about the environmental cost of making batteries out of (toxic?) chemicals then keeping them contained during use as opposed to the environmental cost of building reservoirs. Then there is the cost of replacing worn out batteries versus maintenance on dams and reservoirs.
I imagine that pumped hydroelectric storage might come out ahead in the long run. I don't know. I'd have to look it up but that's my guess.
As for nuclear power versus coal and gas, we still do basically the same thing: We boil water. That water is turned into steam which turns generators. The inefficiencies in the generation process are the same for both. In the end, it comes down to the question of which fuel source is better.
Is nuclear power safer than coal? In the short term, I think not but, in the long term, I think nuclear comes out ahead because, as stated above, burning coal produces pollution that is as bad or worse than the potential of pollution from nuclear fuel. We have to either dispose of nuclear fuel or learn how to recycle it. We have to worry about disasters which would release radiation into the environment but those problems are essentially point-source events. If a problem happens, it happens all at once and has great consequences in the short term. With coal, we don't have to worry so much about short-term disasters but, long term pollution costs might outstrip the superficial benefits.
Again, I don't know for sure but I guess that nuclear power comes out ahead in the long run, provided we accept the caveat that we have to be really freakin' careful. One false move and we've got troubles, Bubbles!
At the end, I come down on the side of pro-nuclear with serious consideration of that caveat. I don't think we know everything we need to know about keeping nuclear power safe and making it better but I think that's because so many people react with knee-jerk fear of it. I think we should hold the line on what nuclear power we have. Don't forge ahead to build more but don't get rid of the plants that are operating now. We should use them to learn from and help us build better ones.
As I said, I hate it when people seem to say that nuclear power is SO BAD that we can't even do research on it. I stipulate that it can be bad but I believe that is the very reason why we should study it. To find out how to keep it from being so bad.
Secondarily, I have always felt that using nuclear reactors to make steam is a waste. Isn't there a way to harness the nuclear reaction to produce electricity directly? I know that there is, in theory, but nobody has figured out how to do it on a sustained level. It would be really cool if we could but, to do that, we need research.
In the mean time, what's the next best thing to coal or nuclear? Hydro is at the top of the list. Isn't it?
Wind, wave and solar are next, after that but I don't think they'll ever be a solution for the long term because you can never count on them being a constant source of power even if you connect the generators into giant grids. Wind is just too unstable. The sun isn't constant and seas can be calm one day and be raging torrents the next. I think they are good ADJUNCTS to our power solution but not the solution by themselves.
That brings us back to coal, hydro and nuclear.
I think we should hold the line on coal: No more but no less. (Unless we absolutely have to build more.) I think we should supplement our coal power with hydro power. I think we should learn to build better nuclear plants then, finally, fill in the gaps with wind, wave and solar power.
Back to the topic sentence: I think pumped storage is in the same department as wind, wave and solar. It's not practical for the long term but as an adjunct, it's good. I think it also might make a good research tool, as well. (i.e. How to build better generators and pumps that are better and more efficient.)
Batteries? Sure I think they'll work but for the long term? I think they are at the bottom of the list.