>>1138457>>1138358>Not using synfuelIt's a straight one-for-one petroleum substitute (often of much higher quality, no less) and can be made from just about any feedstock you want. Biomass? You bet. Natural gas? For shizzle. Gasified coal? Why not? Seawater? Hell, if you've got the additional energy to put into it (i.e. from a reactor or PV panels), sure.
