February 13, 2008
New energy balance study shows Biodiesel EVEN BETTER than last study!
A new analysis shows that the energy balance of biodiesel is a positive ratio of 3.5-to-1. For every unit of fossil energy needed to produce the fuel over its life cycle, the return is 3.5 units of energy, according to new research conducted at the University of Idaho in cooperation with the U.S. Department of Agriculture (USDA). The announcement of the increase up from 3.2 was made today at the National Biodiesel Conference & Expo in Orlando.
The Department of Energy National Renewable Energy Lab (NREL) and USDA had produced the first comprehensive life cycle inventory for biodiesel in 1998. That landmark research found a 3.2 energy balance for biodiesel, while petroleum diesel yielded 0.83 units of energy per unit of fossil energy consumed. The many changes that have occurred in the U.S. biodiesel and agricultural industries since the 1990s prompted researchers at the University of Idaho to update the study in cooperation with the USDA. Both the 1998 and 2007 study are based on biodiesel production from soybeans, which according to U.S. Census data is responsible for more than 80 percent of 2007 estimated biodiesel production. Biodiesels energy balance improved in the 2007 study even though the new analysis is more comprehensive than previous work, and even extends to the energy required to manufacture the farm machinery used to produce soybeans.
"The bottom line is that the energy balance of biodiesel has definitely improved in the last decade," says University of Idaho Department Head of Biological and Agricultural Engineering Jon Van Gerpen. "The increase in soybean yields and a decrease in herbicide use greatly contributed to the increased energy balance. Meanwhile, energy used for crushing soybeans is significantly lower than what was reported in the NREL study.
"For more on this study, read the news release, "Biodiesel Yields Even Higher Energy Balance." Although the University of Idaho study has not been published yet, you can view presentation slides from the conference.