Okay... Asking to see if anyone can let me know the problem here.
We have some clean technologies (wind/solar), but they have serious problems.
One, they're unreliable and not always aligned for peak generation with peak usage. I.e. I posted a couple months ago that the peak in CA for solar generation is during the mid-afternoon hours and peak usage is roughly 4-9 PM when people get home from work.
Two, and related to the first problem, is that we don't have good energy storage capability. Storage could solve the mismatch between generation and usage issue, because then we could use the stored energy for peak usage rather than relying on quick-fired NG or other CO2-generating technology.
We could use battery storage, but building batteries isn't the cleanest from an environmental perspective and will take significant natural resources to scale. I don't think it's economic (although it maybe can be at a home-scale solar / battery combo).
But, we have hydrogen fuel cells. Hydrogen is a zero-CO2 emissions fuel when used in a fuel cell, which converts hydrogen into electricity. The problem is "how do you create liquid hydrogen?" because it tends to be a very electricity-intensive process.
But if we have clean electricity production (wind/solar) and clean usage (hydrogen fuel cells), why don't we use solar/wind to generate liquid hydrogen that we can then store for use in fuel cells for peak demand?
I'm assuming it's inefficient, costly, and thus uneconomical as a storage tech. But I've never investigated so I'm asking all of you.