noun. A fuel, such as biogas or biodiesel, that is produced from renewable resources, especially plant biomass, vegetable oils, or treated municipal and industrial wastes.

noun. Any fuel that is obtained from a renewable biological resource, especially from biomass

"~ New 'biofuel cell' produces electricity from hydrogen in plain air -- "A pioneering “biofuel cell” that produces electricity from ordinary air spiked with small amounts of hydrogen offers significant potential as an inexpensive and renewable alternative to the costly platinum-based fuel cells that have dominated discussion about the “hydrogen economy” of the future, British scientists reported here today.""

2-week  billion-a-year  biodiesel  bottledwater  cellulosic