Ah I think you're correct. I reread your post and I got stuck circular. Yes fixed installations would almost certainly continue not to use liquid fuels just like now. Probably direct solar like you say. And just like now, the transport industry would continue to heavily rely on liq fuels. I'd worry about practical engineering issues with biogas either leaking out (especially if pressurized) or oxygen contamination leaking into the flammability limit range.

If you unleash a chemist and tell him to do anything he wants to make the best energy store, you end up with a liquid hydrocarbon, they really are awesome by both mass and volume energy density and working temp range and corrosion resistance and shelf stability and a bunch of other parameters, even if cost is not an issue. True, weird corner cases like solid rocket boosters do end up with weird fuel components, but they're weird, so that's OK.