One knock against biodiesel has been the relatively large amount of fossil fuel required to produce it. That’s aside from the contentious issue of using arable land to grow crops for fuel, especially food crops. However, a new study of the energy lifecycle of soybean biodiesel reveals a significant improvement in efficiency over the past 20 years or so. Together with the growing use of nonfood feedstocks, the boost in efficiency could make biodiesel production a more sustainable source of energy over the long term.
More Efficient Soybean Biodiesel Production
The new study looks at the fossil energy ratio of soybean biodiesel. Fossil energy ratio, also known as energy balance, measures the units of fossil fuel need to produce a unit of biodiesel. Going back to 1998, previous studies showed a ratio of only 3.2 to 1. A study based on 2002 data showed an improvement of 4.56 to 1. The new study, conducted by the University of Idaho and the U.S. Department of Agriculture, was based on 2006 data, the most recent year available. It showed an improvement to 5.54 units of renewable energy per unit of fossil fuel.
A Renewable Energy Future for Biodiesel Production
As the main drivers behind increased efficiency, researchers cite increased soybean yields, more use of energy-saving farm practices such as minimum tillage, and improved energy efficiency throughout the biodiesel process, from bean-crushing facilities to refineries. This last item is particularly interesting because it hints at the role that renewable energy sources could play in biofuel production, as more large scale wind farms and solar power installations come on line.
Some Hidden Benefits of Biodiesel
As reported by our friends over at Western Farm Press, the USDA researchers note that biodiesel production has helped to spur the agricultural sector to adopt innovative new practices that require less water and fertilizer while improving yields, which provides benefits across the board. While the issue of food vs. non-food use feedstocks will always be a source of tension in the biofuel industry, the improvements revealed in soybean biodiesel production could also indicate greater efficiencies overall in biofuel production, regardless of the source.
New Sources for Biofuels
If push comes to shove and the nation’s agricultural policy turns against growing food crops to make biodiesel and other biofuels, there are plenty of other alternatives in the pipeline that are undergoing efficiency improvements. Just a small sampling: that old standby, waste vegetable oil; non-food, weedy crops including industrial hemp; sewage (yes, sewage!); gooey black trap grease (the cousin of sewage); and, in a sustainability twofer, a bacteria that can transform the glycerol byproduct of biofuel production into a variety of other biofuels including butanol, a direct substitute for gasoline.
Image: Soybeans by kevindooley on flickr.com.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.