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Introduction B iodiesel offers well-publicized envi- ronmental, economic, and n

Introduction B iodiesel offers well-publicized envi- ronmental, economic, and national security beneﬁ ts. Biodiesel combus- tion emits fewer regulated and non-regulated pollutants than petrodiesel (with the possible exception of nitrogen oxides). Further, its lubricity extends engine life, and it is a bio- degradable product. Biodiesel could beneﬁ t farmers and rural communities, depending on ownership of pro- duction facilities and the mix and marketabil- ity of useful co-products. And biodiesel could reduce dependence on foreign oil and associ- ated ﬂ uctuations in availability and price. This publication addresses the sustainability dimensions of biodiesel production and use. These dimensions include the net energy balance of biodiesel relative to other fuels and the link between raising bioenergy crops and sustainable, soil-building prac- tices. Other considerations include the qualities of different biodiesel feedstocks and the economics of production and use. This publication also raises other issues, such as access, scale and ownership of pro- duction, co-product development, and the extent to which biodiesel and other biofuels can effectively replace petroleum fuels. All dimensions of biodiesel production and use are fundamentally intertwined with each other and with the topic of environmental sustainablility. To isolate and address any single aspect of biodiesel invites reference to others. Biodiesel is a renewable and environmentally friendly fuel. This publication surveys many dimensions of biodiesel production and use. Net energy balance, sustainable bioenergy crops, scale of production, consumer access, and the economics of biodiesel are all critical when discussing a sustainable energy future for this country. Above all, increased fuel efﬁ ciency and increased diesel engine use in the United States will be needed in order for biodiesel to become a meaningful part of our energy future. Sunﬂ owers. Photo courtesy of USDA ARS. Introduction ..................... 1 Background and Context .............................. 2 Qualities and Quantities of Biodiesel and Bio- diesel Feedstocks ........... 3 Conclusion ........................ 9 References ......................10 A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.org ATTRA—National Sustainable Agriculture Information Service is managed by the National Cen- ter for Appropriate Technology (NCAT) and is funded under a grant from the United States Department of Agriculture’s Rural Business-Cooperative Ser- vice. Visit the NCAT Web site (www.ncat.org/agri. html) for more informa- tion on our sustainable agriculture projects. /$"5 ATTRA Contents By Al Kurki, Amanda Hill, and Mike Morris NCAT Program Specialists © NCAT 2006 Biodiesel: The Sustainability Dimensions Page 2 ATTRA Biodiesel: The Sustainablility Dimensions Background and Context The Bigger Picture The United States consumes transportation fuels at an extremely high rate per capita compared to other industrialized countries. In 2001, for example, 522 gallons of petro- leum transportation fuels were expended for every man, woman, and child in this coun- try—compared to 421 gallons per capita in Canada, 211 gallons in Germany, and 196 gallons in Japan. (1) Two major policy and practical changes must occur for biodiesel to have a real impact on this country’s energy future: • A national commitment to energy efﬁ - ciency in every facet of American life. This may include community redesign, broad changes in food production and delivery systems, greater commitment to mass transit, and increased mileage efﬁ - ciency for vehicles. • A massive conversion from gasoline-pow- ered autos and light trucks to cleaner- burning diesel autos. This sort of change is not without precedent. U.S. farmers switched from gasoline to diesel powered farm equipment in the late 1970s and ’80s—an important factor in agriculture’s big energy use reduction since the 1970s. Major automakers (General Motors, Toy- ota, Ford, and Daimler-Chrysler) plan to produce more diesel-powered cars for the U.S. market in the years ahead. Most farmers and ranchers operate against tight margins. Capturing energy efﬁ cien- cies and making the best use of biofuels may be nearly impossible without retooling cur- rent food production and distribution sys- tems. For example, when food is shipped over shorter distances, energy consumption and freight costs are reduced. Creating local markets for locally grown foods can accom- plish this. Rotating nitrogen-producing or phosphorous-availing crops with cash crops can save energy on the farm. Changing till- age methods or technologies, and properly scaling equipment to the farm operation can also save energy. These changes may be important precursors to the cost-effective production of biodiesel. Biodiesel as a Transportation Fuel Simply put, biodiesel is the product of mix- ing vegetable oil or animal fat with alco- hol (usually methanol or ethanol) and a catalyst, usually lye. Glycerin is the main by-product. Biodiesel performs very similarly to low- sulfur petroleum-based diesel in terms of power, torque, and fuel efﬁ ciency, and does not require major engine modiﬁ ca- tions. Joshua Tickell, the author of several books on biodiesel, claims it contains about 12 percent less energy than petrodiesel (biodiesel = 37 megajoules per kilogram vs. petrodiesel = 42 megajoules per kilo- gram). This is partially offset by a seven percent average increase in combustion efﬁ ciency of biodiesel. No overall perceived decrease in performance is noted for most vehicles using biodiesel, even though, on average, there is ﬁ ve percent less torque, power, and fuel efﬁ ciency. (2) Biodiesel is considered a safer fuel than petrodiesel. Biodiesel has a high ﬂ ashpoint of over 300ºF (150ºC), compared to 125ºF (52ºC) for petrodiesel. The ﬂ ashpoint is the temperature at which a fuel’s vapor can be ignited. Biodiesel also has a relatively high boiling point and is generally considered safer to handle. Modern diesel fuels are injected into a highly compressed chamber where combus- tion occurs without a spark plug. Biodie- sel reacts more rapidly in the chamber with less combustion delay than most pet- rodiesel fuels and is, therefore, assigned a higher cetane number—the measure of ignition quality. Many of biodiesel’s emis- sion beneﬁ ts stem from its high ignition quality. (3) Biodiesel can be produced from virtually any kind of vegetable oil—new or used. The U.S. Department of Energy estimates that about 26.7 million gallons of biodie- sel were sold in 2003. Total U.S. diesel consumption that year was more than 39.9 billion gallons. (4) Anaerobic Digestion of Animal Wastes: Factors to Consider Biodiesel—a Primer Eﬃ cient Agricultural Buildings: an Over- view Solar-Powered Livestock Watering Systems Wind-powered Electric Systems for Homes, Farms, and Ranches: Resources Organic Soybean Production Sustainable Corn and Soybean Production Oilseed Processing for Small-Scale Producers Moving Beyond Conventional Cash Cropping Related ATTRA Publications Page 3 ATTRA www.attra.ncat.org Qualities and Quantities of Biodiesel and Biodiesel Feedstocks At cold temperatures, diesel fuels form wax crystals that cloud the product and affect fuel performance. This tempera- ture threshold is called the cloud point and occurs at 20º F (-7ºC) for most com- monly used grades of petrodiesel. Biodiesel fuels generally have a cloud point between 25 and 60ºF (4 to 16ºC), depending on the amount of free fatty acids in the prod- uct. Waste vegetable oil contains more free fatty acids (FFAs) than virgin oils. Free fatty acids raise the cloud point of the fuel, so biodiesel made from used cooking oil or ani- mal fat will cloud at higher temperatures than biodiesel made from new vegetable oil feedstock. The American Society for Testing and Mate- rials (ASTM) recommended in 1996 that biodiesel have a cloud point of at most 38º F. The cloud point can be lowered with win- terizing additives formulated for diesel fuels. Biodiesel blends such as B20 (20 percent biodiesel/80 percent petrodiesel) typically require no action beyond that necessary for ordinary petrodiesel. (5) The United States produces approximately 3 to 5 billion gallons of waste vegetable oil every year in restaurants. (7, 8) Much of this product goes to landﬁ lls; some is used in the soap and cosmetics industry. Waste cooking oil could contribute only a small percentage of total U.S. diesel demand. Con- verting this waste into a relatively low-cost resource, however, reduces the environ- mental degradation and costs of disposal in landﬁ lls. The quantity of biodiesel produced from crops is also limited. If rapeseed were grown on every acre of cropland available in the United States in 2002, an estimated 36.3 billion gallons of oil could be produced— very close to current national demand. (6) But of course it is not practical to use all available farmland to produce transporta- tion fuels. Moreover, very serious ethical issues are raised by sacriﬁ cing croplands for vehicle fuel in a world where people are hungry and populations are growing. (For a discussion of the “food vs. fuel” controversy, see the Web site Journey to Forever, www. journeytoforever.org.) Charles L. Peterson, PhD., of the Univer- sity of Idaho, notes that 37 million acres of cropland were reported idle in 2002. That acreage might meet 11 percent of U.S. diesel demand with 3.7 billion gallons of vegetable oil. Practical use of idle land would be less than the 37 million acres, though, because much of the acreage is highly erodible, dry, and has poor soils. Ninety percent of the biodiesel virgin oil feedstock in the United States in 2001 was from soybeans. There are many reasons why uploads/Industriel/ biodiesel-the-sustainablility-dimensions.pdf