The collaborative report between UI and USDA concludes that biodiesel returns 4.5 units of energy for every unit of fossil fuel required in its production. The National Biodiesel Board used the circumstance of the reportˇ¦s publication to criticize the U.S. EPAˇ¦s proposed rule to implement RFS2. "EPA used 2005 baseline numbers for petroleum and biodiesel to project carbon impact 22 years in the future," stated the National Biodiesel Board. "That stacks the deck in favor of petroleum."
New data becomes available as the industry evolves, and agriculture production practices along with energy efficiencies are getting better all of the time. New seed varieties and management practices have reduced the need for pesticides, tilling and fuel, and todayˇ¦s biodiesel plants are more energy efficient.
Some of the data necessary to perform this work, such as energy efficiency numbers, are processed as infrequently as every five years, so researchers can only study it as the information becomes available or is published. UI says the study is one more piece of information that helps to quantify the environmental benefits of biodiesel and includes the most up-to-date data possible.
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Of the energy needed to produce biodiesel, conversion was the most intensive, accounting for about 60 percent of the total energy required in the life-cycle inventory. Soybean agriculture accounted for 18 percent of the total energy requirements, followed by soybean crushing, which required almost 15 percent of the total energy. The secondary inputs added were farm machinery, along with building materials for a crushing plant and biodiesel refinery.
Scientific work regarding renewable fuels is an ongoing endeavor, and members of the team that worked on the 2009 report, including James Duffield and Hussein Shapouri, were involved with NRELˇ¦s energy balance study in 1998, a report thatˇ¦s now considered a landmark in the industry. Shrestha began working with Shapouri and DuffieldˇXon a team that now also includes Michael Haas of USDA Agriculture Research Service and a UI graduate student A. PradhanˇXseveral years after the publication of the original NREL study. The subject has been one of considerable tension, even controversy.
Part of Shresthaˇ¦s ongoing LCA research involved fellow UI professor, Jon Van Gerpen, and an exchange between David Pimentel and Tad Patzek, two notorious California scientists who concluded in a similar study that biodiesel was net energy negative. Pimentel and Patzek claimed that their analysis showed biodiesel production to require 27 percent more fossil energy than is present in the biodiesel, while the 1998 NREL study said biodiesel returned 3.2 units of energy for every 1 unit of fossil fuel used as an input.
ˇ§We have shown that Pimentel and Patzekˇ¦s claim that biodiesel consumes more energy than is provided in the fuel is incorrect,ˇ¨ Shrestha says. ˇ§Pimentel and Patzekˇ¦s study, by subtracting the energy value of the meal directly from the input energy, assumes that the meal is produced with no energy loss (or gain). If losses are present, then they will all be assigned to the biodiesel. This approach can lead to absurd results.ˇ¨
Shrestha is a biodiesel scientist. In addition to his energy balance work, he has studied ways blend levels influence fuel properties such as cloud point and emissions. His research used a "spectrophotometer to scan the blends of U.S. No. 2 diesel and biodiesel from three different feedstocks (rapeseed, soybean and mustard oil) in the visible wavelength range of 380 to 530 [nanometers]," Shrestha stated in a publication for the American Society of Agricultural and Biological Engineers. Using this method, the study was able to distinguish feedstock and blend levels from the fuel sample using light wavelengths.
In the following question and answer session, Shrestha talks about indirect land use, the Energy Independence and Security Act of 2007, process technology upgrades and the role of soybeans in the future of the biodiesel industry.
Q: Regarding the energy balance study you were involved with, Joe Jobe, CEO of the NBB, said: ˇ§This gives Americans even more reason to put their faith in the environmental and societal benefits of biodiesel. The EPA should take this into account when considering biodieselˇ¦s greenhouse gas reductions.ˇ¨ Do you have any response to this?
A: The NBBˇ¦s claim is valid in that soybeans are grown more for meal than they are for oil, so one can argue that increased production for biodiesel increases food production as well. When soybeans are crushed, there is 80 percent meal and 20 percent oil. That means if soybean production is to increase, there is going to be more high-quality protein on the market and therefore cheaper meat. So the case for biodiesel and the case for ethanol are a little different. The oil from soybean crushing is more of a by-product of feed production. I think EPA is using the best available information in its LCA, so as new information becomes available, EPA should definitely incorporate it into its analysis.
Q: What is your opinion on EPAˇ¦s characterization of soy biodiesel as a driver of indirect land use change, or a fuel that has more of a negative greenhouse gas impact than petroleum diesel?
A: We have provided new data and I am confident that the EPA will take this into consideration. They are mandated by the Energy Independence and Security Act of 2007 to investigate indirect land use change that results from biodiesel production. EPA is doing its best, but itˇ¦s not a one-to-one scenario. An additional acre of soybeans in the U.S for biodiesel doesnˇ¦t mean an acre goes into production for food elsewhere as a result. To reasonably address the indirect land use change because of biofuel use, I think it has to be broken down into ˇ§what-ifˇ¨ scenariosˇXhow much forest land will be cleared if the U.S. does, or does not, produce biodiesel. The difference will give the answer of how much biodiesel is responsible for indirect land use change. Itˇ¦s hard to separate these two and itˇ¦s certainly not straightforward, but without this analysis there is no way of knowing how much biodiesel is responsible for all the land use changes that are going around.
Q: What real world impact or influence do you expect the recent energy balance study to have (i.e., can or should a scientific study be able to actually influence, change or edify policy decisions)?
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