We humans really, really love burning shit. Burning shit isn't clean though in either input or output. We could filter and trap the dirty output though, if we really wanted to but the inputs remain retarded on civilisational time-scales.

Fire at a particle level is radiated photons and self-sustaining exothermic reactions, right?
Given enough electricity, is it possible to produce flame in a totally sustainable way? Like something that can be produced at the end of an electricity cable to anywhere, not driving trucks of farmed logs from tree farming facilities to residential areas.