Consider adding some more default fuels to the Coal Generator

[MuteTiefling]

Assuming that you want to keep this to coal like fuels only, I'd recommend adding the following:

'#c:gems/lignite_coal', burn time: 8, '#c:storage_blocks/charcoal', burn time: 80, '#c:storage_blocks/lignite_coal', burn time: 80, '#c:dusts/charcoal', burn time: 8, '#c:dusts/coal', burn time: 8, '#c:dusts/lignite_coal', burn time: 8, '#c:tiny_dusts/coal', burn time: 0.8, '#c:tiny_dusts/lignite_coal', burn time: 0.8, 'evilcraft:blood_waxed_coal', burn time: 16, 'justdirethings:coal_t1', burn time: 24, 'justdirethings:coal_t2', burn time: 72, 'justdirethings:coal_t3', burn time: 216, 'justdirethings:coal_t4', burn time: 648, 'justdirethings:coalblock_t1', burn time: 240, 'justdirethings:coalblock_t2', burn time: 720, 'justdirethings:coalblock_t3', burn time: 2160, 'justdirethings:coalblock_t4', burn time: 6480,

If you're able to read the number of items a piece of fuel can smelt, it'd also be quite possible to translate any fuel item into the generator.

Burn Time = Items Smelted 200 Total Energy = Items Smelted 4000