There are numerous viable storage alternatives; the only open question is which will turn out to be cheapest. Underground compressed air is interesting because it can use otherwise-mothballed turbines. Gravity storage, in the form of a 20,000 ton weight raised and lowered, is low tech. Ammonia and hydrogen are marketable or even directly useful on their own, when tankage is full.
Rooftop and parking lot solar are not nearly enough to meet our energy needs. 1,400 acres per GW! Are there fully-functional farms that can operate on 1,400 covered acres?
Is there a functional gravity storage system on the market today that can store the output of a 1GW plant (besides existing dams, obviously)? Storing hydrogen is a nightmare, and neither Haber-Bosch, Sabatier, nor electrolysis are free.
It's dishonest to hand-wave away the obvious flaws of a technology. It's useful, and we should use it. It's not a panacea.
It's not. It can be stored underground. This is a demonstrated technology, little different from how natural gas is stored.
So is storing enriched uranium. Again this is not a point in favor of nuclear.
Ordinary aluminum contains hydrogen without incident. And, as noted on Wikipedia, "coal gas, 50% hydrogen, was carried in cast iron pipes for a half century without any embrittlement problems".
Carried and stored are different things, tho I'm not an expert on either. I'm getting my info from the US Department of Energy, who reports "Durability of hydrogen storage systems is inadequate. Materials and components are needed that allow hydrogen storage systems with a lifetime of 1500 cycles.". I'm not saying there aren't situations where hydrogen is valuable, but you still haven't demonstrated that we can go carbon-free without nuclear. No one has, because the math doesn't add up, at least not so far.
https://www.energy.gov/eere/fuelcells/hydrogen-storage-chall....
"Benefit from partial shade" means exactly that. Any 2800-acre farm that welcomes 50% shade, or any four such 700-acre farms, can. But there has thus far been no demand for the technique, because there is in fact no shortage yet of land for 100% coverage. I have personally seen a large number of fully shaded parking lots; I daresay you have, too.
Solar farms do not need 1400 connected acres. Fourteen 100-acre solar farms are more useful, producing a peak 71 MW each. In my immediate area, just recently, a decommissioned 20-acre landfill ("It’s not exactly a tourist area") was turned into a solar farm, producing useful power the very same year as it began construction. <https://highlandscurrent.org/wp-content/uploads/2018/06/Sunl...>
Canals in India are being roofed over with solar panels, reducing evaporation loss. <https://en.wikipedia.org/wiki/Canal_Solar_Power_Project> Panels are being floated on hydroelectric dam reservoirs, all over the world, for the same benefit, with easy access to the power grid. Los Angeles could float 175 acres of panels over its municipal reservoir, replacing the black plastic balls it floats today to absorb sunlight that would produce bromates. <https://www.sciencealert.com/here-s-what-s-really-going-on-w...>
Railroad rights-of-way are similarly available.
A large fraction of carbon-neutral power comes from wind turbines, which also have encountered no difficulty locating space to operate, already often shared with existing farms and ranches.
Air compression is familiar tech.
So, the only remaining question is which of the others will turn out to be cheaper than air. Hydrogen is essential feedstock in many industries, where storage and handling have long since been worked out, so synergy may push H2 over the line, particularly once it becomes the dominant aviation fuel. There is of course no difficulty with storing or using ammonia, and similar synergies apply. Modern catalytic methods are much more efficient than traditional Haber-Bosch, Sabatier, or electrolysis processes, so costs are plummeting, and the ultimate winner, if there is only one, is unpredictable. In other words, they are all viable, and getting better.
In all cases the costs are still in free fall, so nukes, as already mature tech, fall progressively farther behind.
Even if Wind/Solar-only was viable (it's not), available everywhere (it's not), and substantially cheaper over the lifetime of the plants (it's competitive) it would not make sense to rely only on wind and solar. Besides the intermittency, it still takes 3.125MM solar panels for a 1GW plant according to the USDOE. By my math, that requires 1,400 acres of land just for the space the panels cover. Even if you improve on that, you are still talking about ~1,000 acres. And we'd need to build over-capacity to charge the batteries (more mining-intensive materials) for when power generation is low, it would require 2-4x the land.
That's a LOT of land! It would still make sense to me to replace NatGas with cheap, carbon-free nuclear power and it's small physical footprint.