Right outta WWII--woood gasification for engine fuel
Way back when I was in engineering college I had a part time job working at a D.O.E. research facility called GROW, (Gasification Research on Wood). Basically using a massive heat exchanger to release flammable gases off of various combustibles like different types of wood chips. I remember there was one Doctoral Candidate from China that was using rice hulls. It was a very nasty and dangerous environment to work in but I was cheap grunt labor.