The economics of this sort of thing is full of surprises.
Someone with a solar farm who cannot sell the excess they produce at noon (local utility won't take it) can put it into producing methane to sell (or use), if the equipment is cheap enough to amortize over only the over-productive intervals. And claim extra carbon credits for displacing mined methane. They might install some extra panels to increase the intervals. Displacing methane they would have had to buy yields more value.
Probably in the future it will be more profitable to produce ammonia instead. Ammonia is even more useful than methane.
Yes, the equipment needs to be cheap if it's not running very often, or it won't pay off.
That's their whole thing — they deliberately save on capex by accepting lower efficiency, because that in turn allows running it intermittently on cheap solar without extra costs like batteries or having to run on more expensive power in the night etc.
I have no idea how realistic their end game is, but the general approach seems like a smart idea.
https://caseyhandmer.wordpress.com/2023/08/16/how-to-produce...
Ammonia has the mild issue that it's not just flammable, but toxic and flammable!