Biomass refers to wood and other plant or animal matter that can be burned directly or can be converted into fuels. Wood has historically been a source of fuel. Now, technologies exist to convert plants, garbage and animal dung into natural gas. Methanol fuel, or wood alcohol, is a volatile fuel that has been used in race cars for years. Another alcohol, clean burning ethanol, which can be produced from sugarcane, can be blended with gasoline to form a blended fuel (gasohol) and used in conventional automobile engines, or used as the sole fuel source for modified engines. Synthetic fuels are fossil fuel substitutes created by chemical reactions using such basic resources as coal or biomass. Synthetic fuels are used as substitutes for conventional fossil fuels such as natural gas and oil.
There are several ways to convert biomass into synthetic fuels, or synfuels. Oils produced by plants such as rapeseed (canola), sunflowers and soybeans can be extracted and refined into a synthetic diesel fuel that can be burned in diesel engines. Thermal pyrolysis and a series of catalytic reactions can convert the hydrocarbons in wood and municipal wastes into a synthetic gasoline.
One difficulty with the exploitation of biomass fuels is the potential impact on the ecology of the region. For example, excessive use of dung and crop residues for fuel instead of fertilizer can deprive the soil of essential nutrients that are needed for future crops.