It could be ethanol which can be used in petrol engines. The fuel I mentioned is often called Bio Diesel.
Bio diesel is often made from a waste product (WVO) that used to be land filled so it is not depriving people of food.
In America there is a patent for a system that uses clear plastic tubes that grow an algae on the inside. The algae grows with moisture and sunlight. This yields a high amount of product owing to the large surface area inside the tube. The algae is then extracted and can make bio diesel. These tubes can be placed in areas unsuitable for conventional farming techniques.
The process doesn't always have to deprive people of food. Bio diesel from vegetable oil (if well made) has been found to be cleaner in the gas outputs than conventional diesel, with the exception of Nitrous Oxide, which can be brought to the same level as normal grade diesel with an adjustment in engine timing.