Given that it seems you can make a https://en.wikipedia.org/wiki/Briquette out of pretty much anything solid that can burn, it would be nifty if any solid with fuel content could be pelletized into 1MJ chunks.
Perhaps the most general implementation would be a something like omnifluid's burner 'offshore' pump. It accepts burnable fuel, and produces 'free' objects based on burning that fuel. Have the burner accept anything, 'burn' it and produce a pellet for each MJ of input energy.
