Tanks filled with ethanol made from the adjacent fields of sugar cane are seen in this view of Brazil’s biofuel enterprise.

Bioenergy is energy derived from recently living organisms.

Bioenergy does not contribute to climate change because the carbon dioxide (CO₂) it produces is derived from carbon that existed in the atmosphere in the form of another recently living thing. Fossil fuels, on the other hand, release into the atmosphere greenhouse gases that were previously encased within the earth.

Biomass is the total mass of living matter within a given habitat, including commonly used fuels such as wood, but also a lot of items usually thought of as waste: agricultural waste, dung, municipal solid waste, industrial waste, and some crops that may be cultivated expressly for their use as fuels. Another attractive feature of biomass: It’s just about everywhere, not concentrated in a few countries.

Biomass is easy to grow, collect, use, and replace without depleting natural resources, so bioenergy is not only renewable, but also sustainable.

Ethanol, or ethyl alcohol as used in drinks and medicine, is currently the most widely used biofuel in the United States. About one-third of the U.S. corn crop is directed into ethanol production. This has led to a threefold increase in the amount of ethanol produced annually in the United States since 2003. About 34 billion kiloliters of ethanol were produced in the United States in 2009.

The U.S. Department of Energy supports research into new and cost-effective methods of developing liquid transportation fuels from abundant biomass sources such as crop and forestry residues.