I feel like you have only been reading a small part of what I've been saying, replying to that, and ignoring the rest. It seems to me that the sheer amount of solid fuel needed to keep several of these things going to generate enough heat to run the second tier large boiler is simply unrealistic. Also why should you go back to trying to mass produce insane amounts of solid fuel long after you have abandoned it in favor of liquid and gas? I mean oil is what you are supposed to fuel things with late game aren't you? So why does the big badass end game dynamo seemingly now require you to go back to mass producing charcoal?
Even in present mankind still using solid fuel for genereting energy => coal powerplant, or produce heat in some houses. So this tech isnt obsolete