"we're a long way" ignores that we have made progress, and there are several proposals to use Solar and Wind power to do this, and investments in newer reaction chambers. Fortesque mining (Australia) for instance is quite highly invested in this, and believes its close enough to commercially viable to dig ground on production facilities.

I agree it's going to be only viable in a highly distorted market initially, but let's not pretend this isn't normal, when you build out a new industry.

Electrolysis is being performed on an industrial scale already.

Its only serious difficulty is inefficiency, but when the power is free (i.e. renewable production in excess of immediate demand) inefficiency is just a yield problem. Anyway efficiency in excess of 80% has been demonstrated. The key seems to be keeping the product gases from clustering around the electrodes, crowding out the water feedstock. So, pores too small for O2.

As a limit on efficiency, energy lost when the O becomes O2 may be hard to recover. There seems reasonable hope of both H in the H2 coming from the same H2O, given a catalytic electrode surface.

Every large producer of power from renewables will be synthesizing H2 or NH3 for sale during periods of overproduction, regardless of what other storage and backup methods they rely on. The market for those materials will prove unlimited, and tankage and shipping are dirt cheap. Shipping, BTW, is gearing up to transition to LNH3 fuel.

But maybe not that far?

https://group.vattenfall.com/what-we-do/roadmap-to-fossil-fr...