A biofuel may be a fuel that's produced through contemporary processes from biomass, instead of a fuel produced by the very slow geological processes involved within the formation of fossil fuels, such as oil. Since biomass technically are often used as a fuel directly (e.g. wood logs), some people use the terms biomass and biofuel interchangeably. More often than not, however, the word biomass simply denotes the biological staple the fuel is formed of, or some sort of thermally/chemically altered solid outcome , like torrefied pellets or briquettes. The word biofuel is typically reserved for liquid or gaseous fuels, used for transportation.