There are several types of bioenergy, including biofuels, biogas, and biomass. Biofuels are liquid fuels such as ethanol and biodiesel that are produced from crops such as corn, sugarcane, and soybeans. Biogas is a mixture of methane and carbon dioxide that is produced from organic waste materials through a process called anaerobic digestion. Biomass is a solid fuel that is derived from plant and forest materials.