True. Come to think of it, perhaps I should've replaced every mention of "coal" with "xychorium." Unless xycraft makes that renewable, too.
It's also possible to make a fully automated Scrapbox producer with Deployers. That was fun to make, though it produces a heck of a lot of Wooden tools that no one will ever use.
Aren't there more Scrapbox-based sources of Coal? Coal Dust, also Scrapboxed a bit, can be smelted into Coal, and I don't know, perhaps Hydrated Coal Dust is produced by Scrapboxes?
I'm not sure about hydrated coal dust, but you can get some really weird and obscure stuff from scrapboxes so who knows. Plus the wonders of scrapboxes is that all the useless crap, like wood tools, can just be converted into more scrap, which can be used to produce more scrapboxes and more crappy wooden tools! Hurray!