A Continuing Effort

Product life-cycle analysis is a relatively new but important science to the renewable fuels industries. In conjunction with the USDA, University of Idaho researchers have produced a new energy balance study for soy biodiesel concluding that methyl ester manufacturing returns more than four times the fossil fuel energy it requires. Biodiesel Magazine talks with UI・s Dev Shrestha about the study・s details.
By Nicholas Zeman | December 21, 2009
As a professor of agricultural and biological engineering at the University of Idaho in Moscow, Idaho, Dev Shrestha is part of a high-profile team that recently published a new energy life-cycle analysis (LCA) of soy biodiesel. Assessing the energy balance of soy biodiesel is a continuous effort. UI and USDA have been involved with the project for yearsXand they・ve found that biodiesel・s numbers keep improving. Combining economic and engineering sciences, the study has given the government a tool through which to make informed energy policy decisions, Shrestha says.

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 report・s publication to criticize the U.S. EPA・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 today・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.

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 NREL・s energy balance study in 1998, a report that・s now considered a landmark in the industry. Shrestha began working with Shapouri and DuffieldXon a team that now also includes Michael Haas of USDA Agriculture Research Service and a UI graduate student A. PradhanXseveral years after the publication of the original NREL study. The subject has been one of considerable tension, even controversy.

Part of Shrestha・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.

:We have shown that Pimentel and Patzek・s claim that biodiesel consumes more energy than is provided in the fuel is incorrect,; Shrestha says. :Pimentel and Patzek・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.;

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: :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 biodiesel・s greenhouse gas reductions.; Do you have any response to this?


A: The NBB・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 EPA・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 it・s not a one-to-one scenario. An additional acre of soybeans in the U.S for biodiesel doesn・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 :what-if; scenariosXhow 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. It・s hard to separate these two and it・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)?


A: The main objective of energy life-cycle analysis is to see if biodiesel is as renewable as we thought it was 10 years ago. It・s not 100 percent renewable because it takes quite a bit of fossil fuel to produce. So we want to know, :How renewable is it?; We want to know how much is gained from using petroleum to produce other types of fuel. In our study, we found that for every unit of fossil energy biodiesel requires for production, 4.5 units of energy are returned on the backend. So we are liberating our petroleum use. There・s a tremendous opportunity to apply that result in policy making.



Q: What is the best way, in your opinion, for the energy used for crushing soybeans to be allocated between meal and biodiesel production?

A: Soybean crushing yields 80 percent meal and 20 percent oil, so we allocated 80 percent of the energy required by crush operations to the meal and 20 percent to the oil. These are fixed numbers that don・t change. Other methods include replacement method or market values of the coproducts to assign energy values. I・m not saying it・s a wrong method, but for us it・s a moving target because it is always changing.


Q: Soybean meal is a major agricultural feed and was before the build-out of the biodiesel industry. Should biodiesel be considered an added-value product of soy meal production practices? Can this be an argument against those who see biodiesel as a negative influence on food production and prices?


A: As we discussed earlier, soybean oil is more of a byproduct of soybean meal market. If biodiesel makes soybean production more profitable, that is a good thing for food markets because more soybean production means more high-quality protein meal production and, down the road, reduced food prices. The U.S.・s surplus oil and fat production for 2005, after accounting for food related consumption, imports and exports, was 6.4 billion pounds. This amount of oil and fat will produce about 850 million gallons of biodiesel. Therefore, until now, I would say biodiesel has not competed with food markets at all.


Q: A significant portion of the study refers to agricultural practices and improvements in soya cultivation. Is this an area that has been overlooked by EPA and others when making determinations about biodiesel・s environmental impact?

A: We have used the most up-to-date information and data possible in our analysis of soybean production practices. In addition, we made sure that a single year・s data be used for all agricultural inputs for consistency. The study does not include the fact that soybeans fix nitrogen, which can be used in subsequent crop production in rotations. Life-cycle analysis, as a science, has had a relatively short developmental process so some things are missed. I am not sure if EPA has included this factor in its analysis yet, but I have no doubt that one day everything will be included and everything will be sorted out.


Q: The industry has seen a major increase in the use of waste greases, tallow and other feedstocks for methyl ester manufacturing. What role do you see soybeans playing, as the industry continues to evolve?


A: The price of soybean oil has been high lately so the level at which soybeans are used as a feedstock certainly has a lot to do with the market price. Use of other feedstocks has been increasing and we・ve seen the use of soybean oil as a biodiesel feedstock drop by 30 to 40 percent in the past few years. However, to meet the EISA mandate for [biomass-based] diesel, the industry still has to use soybean oil to reach that target.


Q: You mention the incorporation of energy saving techniques utilized by the biodiesel industry over the past few yearsXbut as production facilities are often strapped for cash, how widespread do you think the retrofitting of facilities with the most up-to-date process technologies really is?


A: The industry is strapped for cash so there has been a limitation on improvements. The majority of biodiesel, however, is being produced by a small number of big companies like ADMXso modest improvements can have a big impact. But on the business side, the companies that are incorporating energy-saving technologies will be the ones that survive, and there will be more improvements down the road.


For a full version of the study, :Energy Life Cycle Assessment of Soybean Biodiesel,; visit www.usda.gov/oce/global_change/index.htm.


Nicholas Zeman is an associate editor for Biodiesel Magazine. Reach him at (701) 738-4972 or nzeman@bbiinternational.com.
 
 
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