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Energy, Biofuels & Climate Change
Fossil fuels – such as coal, natural gas, and oil – provide most of the energy used in the United States but contribute to climate change and other environmental problems. EPA's climate programs provide models and methods to inventory greenhouse gas emissions and assess the effects of global change on human health, the environment, and the economy in the U.S. Many EPA programs promote more efficient energy use and improvement of environmental quality without disrupting energy supplies. Efforts are now underway to promote renewable energy sources and the sustainable production of biofuels.
Biofuels are renewable fuels derived from biomass – organic material from plants and animals; the energy in biomass can be accessed by conversion of the raw feedstock material, such as starch and cellulose, using biochemical or thermochemical processes and resulting in such bio-based fuels as ethanol, methanol, diesel, gas, crude, and methane. Agricultural products that may be specifically grown for conversion to biofuels include corn, soybeans, and sugarcane. Domestic biomass sources include agricultural and forestry residues, municipal solid wastes, industrial wastes, and terrestrial and aquatic crops cultivated to produce renewable energy. Continuing research will refine the processes for conversion to biofuels of such non-grain sources as switchgrass, tree crops, algae, and forestry waste.
Biodiesel is made from biomass raw material including soybeans, algae, used vegetable oil, and animal fats such as beef tallow and fish oil. Biodiesel burns more cleanly than conventional diesel, thus reducing emissions of asthma-causing soot and other harmful air pollutants. Furthermore, when used cooking oil is recycled to produce biodiesel, billions of gallons of waste grease can be diverted from landfills and municipal water pipes, improving the quality of both air and water. It may be blended with conventional fossil-based diesel to obtain different blends such as B2 (2% biodiesel and 98% conventional diesel) or B20 (20% biodiesel) or it can be used as 100% biodiesel (B100).
Bioethanol is an alcohol produced through fermentation of yeast. The sugars to feed the yeast can be derived from a variety of sources such as grains, sugar cane, and cellulose in the cell walls of plants obtained either from agricultural waste or dedicated energy crops such as switchgrass. Bioethanol also burns cleaner than unleaded gasoline, producing lower emissions of particulate matter and toxics. Production of cellulosic ethanol from agricultural or forestry residue can and conserve agricultural lands and reduce the pressure on landfills.
Currently all ethanol produced in the U.S. comes from corn starch. However, the 2007 Energy and Independence Security Act (EISA) calls for the production in 2022 of 21 billion gallons per year (BGY) of cellulosic ethanol and other advanced biofuels. Bioethanol can be blended with conventional gasoline to produce E10 (10% ethanol and 90% gasoline) and E85 (85% ethanol and 15% gasoline).
The successful development, expansion, and use of biofuels are important elements of national policies promoting renewable energy and the reduction of greenhouse gas emissions. EISA aims to significantly accelerate the production of biofuels, reducing reliance on fossil-based fuels. EISA’s timetable calls for increasing total biofuel production from 4 BGY in 2006 to 36 BGY by 2022 – which could supply more than 20 percent of U.S. demand for gasoline by 2022.
EISA makes EPA responsible for revising and implementing regulations to ensure that gasoline sold in the United States contains at least a threshold volume of renewable fuel. The Renewable Fuel Standard program will increase the volume of renewable fuel required to be blended into gasoline from 9 billion gallons in 2008 to 36 billion gallons by 2022. The 2009 RFS-2 program regulations are being developed in collaboration with refiners, renewable fuel producers, and many other stakeholders.
Existing EPA regulations affect the production and use of biofuel across the biofuel supply chain. The 2007 Energy and Security Act aimed at increasing the biofuel production from 9 billion gallons per year (BGY) in 2008 to 36 BGY by 2022. EPA is responsible for proposing rules in a revised Renewable Fuel Standard (RFS-2) that will govern how biofuels are produced and used in the U.S. EPA anticipates proposing RFS-2 in 2009 and implementing its new provisions in 2010.
The future years will undoubtedly see significant changes throughout the biofuel supply chain (illustrated in the figure below). Feedstock production, for example, may evolve through changes in such areas as land use, crop selection, tilling practices, and application rates of water, fertilizer, and pesticide. An ongoing challenge for EPA is to understand, monitor, and anticipate environmental and health impacts resulting from current and future generations of the biofuel system.
EPA has contributed significantly to the understanding of current and potential future variations in the biofuel supply chain through its report, Biomass Conversion: Emerging Technologies, Feedstocks, and Products (PDF) (36 pp, 1.9MB). This study describes the diverse technologies from feedstock production and processing, through conversion to sugars and other intermediate products, followed by conversion to energy and other final products. EPA will continue to play a major role in researching the potential impacts of the biofuel system on human health and the environment, in accord with the federal government’s National Biofuels Action Plan (PDF) (24 pp, 5.0MB).
EPA is legally responsible for developing standards that limit chemical emissions that may arise from technologies and practices at biorefineries. State agencies implement these standards through their permitting programs, using the standards to determine whether to issue permits for operation of biorefineries.
The recent increase in biofuel production facilities and the emerging new technologies for refining biofuels present new challenges to government and business alike. EPA and other regulatory agencies must develop means to ensure that any negative impacts from biofuel production do not harm human health or the environment, and the biofuel industry must comply with regulations concerning construction and operation of facilities for biofuel production.
EPA’s Region 7 has developed two manuals outlining environmental laws applicable to the construction and operation of production facilities for ethanol (PDF) (104 pp, 3.2MB, About PDF) and biodiesel (PDF) (144 pp, 6.4MB, About PDF) respectively. The manuals provide extensive guidance that underscores the key roles played by EPA, states, and facility operators concerning critical issues related to biofuel production.
Expanded production and use of biofuels are important elements of national policies promoting renewable energy, reduced greenhouse gas emissions, and decreased reliance on imported fossil fuels. The sustainability of the biofuel supply chain from feedstock production to end use will determine the degree to which biofuels reach their full environmental potential and reduce reliance on petroleum. Given the reliance of the biofuel system on natural resources, assuring that the biofuel system proceeds in an environmentally sound manner is essential for its success, as well as for the health of humans and the ecosystem.