A biofuel is a renewable energy source made from organic matter or waste. Because biofuels can be carbon neutral, or even carbon negative, they play an important role in decarbonizing the production of electricity.
There are two categories of biofuels: primary biofuels that are used directly without conversion to create useful energy; and secondary biofuels that are created through a conversion process that uses a primary biofuel as an input. A primary biofuel is called biomass. Types of biomass include agricultural crops, animal waste, forestry waste, fishery bi-products, municipal waste, and food service by-products and waste. Secondary biofuels include bioliquids and biogases and are created through a conversion process that uses biomass as an input. Conversion methods for secondary biofuels include liquid fuel conversion, gasification, and digestion.
Solid biofuels can be burned directly to create heat for space heating or industrial processes and to create steam for use in heating, industrial processes, and/or electricity generation. Liquid biofuels can replace traditional liquid fuels such as gasoline or oil for uses such as transportation or electricity generation. And gaseous biofuels can be used as a supplement or replacement for natural gas and other gaseous fuels.