Diesel engines can run on just about anything, including used cooking oil. An entire industry is emerging to provide brave 'biodiesel' pioneers with the ingredients for petroleum-free motoring. One day last March, my musician friend Jonathan drove up in a Mercedes. This was odd, since Jonathan is so resolutely counterculture that he once tried recording an album in the woods, without electricity. His car's exhaust smelled faintly of french fries, and therein lay the explanation: The new Jonathan Richman tour vehicle -- an '84 300D Turbo -- was running on vegetable oil-derived biodiesel fuel as he and his drummer crisscrossed...