Plant material is used in a variety of ways to create energy: combusted to produce heat or electricity; anaerobically digested to produce methane; and converted to ethanol, biodiesel, or hydrogenated vegetable oil for fuel. Within transportation, bioenergy makes up almost 3 percent of fuel consumed. Within the power sector, it comprises 2 percent of the total.
From a climate perspective, whether plant material used for bioenergy is annual or perennial (or waste content) makes all the difference. Because energy inputs for annual bioenergy crops, such as corn, are so high, they make little progress on cutting emissions.
Perennial bioenergy crops—such as switchgrass, fountain grasses, silver grass, poplar, willow, eucalyptus, and locust—can be different. Cultivated appropriately, they can reduce emissions by 85 percent compared to corn ethanol. Replacing annuals with perennials also raises carbon sequestration in soil.
Many perennial bioenergy crops are prime candidates to grow on degraded land not suited to food production. Compared to corn and other annuals, perennials can prevent erosion, produce more stable yields, be less vulnerable to pests, and support pollinators and biodiversity.
bioenergy [in transport and]…power: REN21. Renewables 2016 Global Status Report. Paris: REN21 Secretariat, 2016.
bioenergy…projected to grow: IEA. Medium-Term Renewable Energy Market Report 2015. Paris: International Energy Agency, 2015.
United States…corn…ethanol: REN21, Renewables 2016.
Perennial bioenergy crops can be different: El Bassam, N. Handbook of Bioenergy Crops: A Complete Reference to Species, Development, and Applications. London and Washington, D.C.: Earthscan, 2010.
emissions…compared to corn ethanol: Charles, Chris, and Ivetta Gerasimchuk, Richard Bridle, Tom Moerenhout, Elisa Asmelash, Tara Laan. Biofuels—At What Cost? A Review of Costs and Benefits of EU Biofuel Policies. Winnipeg: The International Institute for Sustainable Development, 2013; Conca, James. “It’s Final—Corn Ethanol Is of No Use.” Forbes. April 20, 2014; Smith, Pete, Mercedes Bustamante, Helal Ahammad, Harry Clark, Hongmin Dong, Elnour A. Elsiddig, Helmut Haberl et al. “Agriculture, Forestry and Other Land Use (AFOLU).” In Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK, and New York: Cambridge University Press, 2014.
grow on degraded land: Mehmood, M.A., et al. “Biomass Production for Bioenergy Using Marginal Lands.” Sustainable Production and Consumption 9 (2017): 3–21.
[benefits of] perennials: Whirling, Ben P., et al. “Perennial Grasslands Enhance Biodiversity and Multiple Ecosystem Services in Bioenergy Landscapes.” Proceedings of the National Academy of Sciences 111, no. 4: 1652-1657.