Ethanol was first used as a fuel in 1894. In Brazil, in 1973, they began to do in big way. They have abundant cassava and sugar cane. Hydrolysis of wood, bagasse, straw, paper, cotton, to sugar is a major problem. This can be done by acid hydrolysis under pressure or cellulase enzymes.
Sugar cane is one of the most efficient plants.
The materials are already collected, but not all are used. Generally alcohol is two to four times more expensive than gasoline. These are already similar to diesel fuels in many of their properties. They can probably be used without major work except for economics. They will work in basically unaltered diesel engines, but gums and waxes must be removed.