California's first attempt to turn rice shubble and tree trimmings into ethanol resembles a scene from "Back to the Future," the 1980s movie in which trash was dumped into one end of a machine and pure energy comes out the other. The proposed "bio-refinery" will convert thousands of tons of rice-straw, orchard prunings and other agricultural waste into ethanol, which state air pollution fighters hope will soon replace the unpopular additive MTBE in California gasoline.