Researchers identify energy gains and environmental impacts of corn ethanol and soybean biodieselJuly 12, 2006The first comprehensive analysis of the full life cycles of soybean biodiesel and corn grain ethanol shows that biodiesel has much less of an impact on the environment and a much higher net energy benefit than corn ethanol, but that neither can do much to meet U.S. energy demand. The study will be published in the July 11 Proceedings of the National Academy of Sciences. The researchers tracked all the energy used for growing corn and soybeans and converting the crops into biofuels. They also looked at how much fertilizer and pesticide corn and soybeans required and how much greenhouse gases and nitrogen, phosphorus, and pesticide pollutants each released into the environment. "Quantifying the benefits and costs of biofuels throughout their life cycles allows us not only to make sound choices today but also to identify better biofuels for the future," said Jason Hill, a postdoctoral researcher in the department of ecology, evolution, and behavior and the department of applied economics and lead author of the study. The study showed that both corn grain ethanol and soybean biodiesel produce more energy than is needed to grow the crops and convert them into biofuels. This finding refutes other studies claiming that these biofuels require more energy to produce than they provide. The amount of energy each returns differs greatly, however. Soybean biodiesel returns 93 percent more energy than is used to produce it, while corn grain ethanol currently provides only 25 percent more energy. Still, the researchers caution that neither biofuel can come close to meeting the growing demand for alternatives to petroleum. Dedicating all current U.S. corn and soybean production to biofuels would meet only 12 percent of gasoline demand and 6 percent of diesel demand. Meanwhile, global population growth and increasingly affluent societies will increase demand for corn and soybeans for food. The authors showed that the environmental impacts of the two biofuels also differ. Soybean biodiesel produces 41 percent less greenhouse gas emissions than diesel fuel whereas corn grain ethanol produces 12 percent less greenhouse gas emissions than gasoline. Soybeans have another environmental advantage over corn because they require much less nitrogen fertilizer and pesticides, which get into groundwater, streams, rivers and oceans. These agricultural chemicals pollute drinking water, and nitrogen decreases biodiversity in global ecosystems. Nitrogen fertilizer, mainly from corn, causes the 'dead zone' in the Gulf of Mexico. "We did this study to learn from ethanol and biodiesel," says David Tilman, Regents Professor of Ecology and a co-author of the study. "Producing biofuel for transportation is a fledgling industry. Corn ethanol and soybean biodiesel are successful first generation biofuels. The next step is a biofuel crop that requires low chemical and energy inputs and can give us much greater energy and environmental returns. Prairie grasses have great potential." Biofuels such as switchgrass, mixed prairie grasses and woody plants produced on marginally productive agricultural land or biofuels produced from agricultural or forestry waste have the potential to provide much larger biofuel supplies with greater environmental benefits than corn ethanol and soybean biodiesel. According to Douglas Tiffany, research fellow, department of applied economics and another co-author of the study, ethanol and biodiesel plants are early biorefineries that in the future will be capable of using different kinds of biomass and conversion technologies to produce a variety of biofuels and other products, depending upon market demands. Hill adds that both ethanol and biodiesel have a long-term value as additives because they oxygenate fossil fuels, which allows them to burn cleaner. Biodiesel also protects engine parts when blended with diesel. "There is plenty of demand for ethanol as an additive," Hill says. "The ethanol industry was built on using ethanol as an additive rather than a fuel. Using it as a biofuel such as E85 is a recent and currently unsustainable development. As is, there is barely enough corn grown to meet demand for ethanol as a 10 percent additive." University of Minnesota |
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| Related Biodiesel Current Events and Biodiesel News Articles U of Minnesota researchers discover high levels of estrogens in some industrial wastewater In a groundbreaking study, civil engineering researchers in the University of Minnesota's Institute of Technology have discovered that certain industries may be a significant source of plant-based estrogens, called phytoestrogens, in surface water. 'Green' energy from algae In view of the shortage of petrochemical resources and climate change, development of CO2-neutral sustainable fuels is one of the most urgent challenges of our times. Biodiesel on the wing: A 'green' process for biodiesel from feather meal Scientists in Nevada are reporting development of a new and environmentally friendly process for producing biodiesel fuel from "chicken feather meal," made from the 11 billion pounds of poultry industry waste that accumulate annually in the United States alone. Extreme makeover chemistry style In revisiting a chemical reaction that's been in the literature for several decades and adding a new wrinkle of their own, researchers with Berkeley Lab and the University of California (UC) Berkeley have discovered a mild and relatively inexpensive procedure for removing oxygen from biomass. Shatter-resistant brassicas An international team of scientists has cracked the problem of pod shatter in brassica crops such as oilseed rape. Microscopic manufacturers produce eco-friendly plastics Last year's energy crisis highlighted an unforseen by-product of the looming fuel shortages of the 21st century. Petroleum-based products such as plastics that society takes for granted but now requires to function will run out with the oil. 'Green' Plastics Could Help Reduce Carbon Footprint More than 20 million tons of plastic are placed in U.S. landfills each year. Results from a new University of Missouri study suggest that some of the largely petroleum-based plastic may soon be replaced by a nonpolluting, renewable plastic made from plants. Trailblazing rural community shows green heating oil a viable option Local schools and homes in the small Georgian town of Reepham in Norfolk are taking part in the groundbreaking 12-month trial, led by the University of East Anglia (UEA). Microbes fuel energy debate Microbes may well be the answer to our global energy crisis. By fermenting biomass to produce biofuels, they offer a possible climate-friendly solution to the anticipated shortfall in fossil fuel supply. New NIST method accelerates stability testing of soy-based biofuel The National Institute of Standards and Technology (NIST) has developed a method to accelerate stability testing of biodiesel fuel made from soybeans and also identified additives that enhance stability at high temperatures. More Biodiesel Current Events and Biodiesel News Articles |
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