Fuel cells are a high capital cost solution to the problem of turning hydrogen into electricity, at higher efficiency. That's not what solar or wind need -- they need low capital cost, mediocre efficiency backup sources.
This is pretty much entirely because PV keep getting cheaper faster than everyone expected — even as recently as five years ago, pessimism like yours wouldn’t have been unreasonable, and yet the problem is now essentially solved and all we need to do is build the stuff at the prices we can already afford.
{1} https://web.archive.org/web/20120322204531/http://www.grid-s...
{2} https://cleantechnica.com/2018/06/14/new-us-solar-record-2-1...
Solar is less then 1% and that's with 300% increase it's not even close to being able to deliver baseline anything regardless of how cheap it gets. It's a dream that's not even close to be realistic and frankly highly naive.
Again 47w per m2 vs. 1000w per m2 and with solar panels needing continous repeairs and no grid or fuel cells in sight plus reliance on coal, nuclear and oil for when the sun doesn't shine.
Good luck.
This is why you're not seeing new nuclear plants much in the west. The decision makers know they face huge risk from future cost declines of renewables which, combined with gas, would leave those reactors unable to amortize their construction, financing, and fixed operating costs.
There are other solutions for long term storage of renewable energy to make it dispatchable. For example, making hydrogen, then burn it in turbines. The efficiency of this is lousy, but the capital cost can be quite low.
