If the Missouri Department of Transportation improved its sources of biodiesel, the department would be able to meet a state mandate that calls for fueling at least 75 percent of its diesel fleet and heavy equipment with biodiesel. That suggestion is part of a list of best practices being developed for MoDOT by a University of Missouri-Rolla researcher.

Dr. Scott Grasman, associate professor of engineering management and systems engineering at UMR, is working with MoDOT to create a set of steps the department can take to improve its consumption of B-20, a blend of 20 percent by volume biodiesel with 80 percent by volume diesel.

A legislative mandate, revised last August, required MoDOT to fuel at least 75 percent of its diesel vehicle fleet and heavy equipment with B-20. Last year, biodiesel accounted for 51 percent of the 6 million gallons the department consumed.

“B-20 is more environmentally neutral and has lower greenhouse emissions,” Grasman explains. “Although biodiesel is probably not the best long-run alternative fuel source, it’s a more renewable fuel that can come from vegetable oils, animal fats, or really any biomass. That’s one reason it’s a good regional alternative.”

While biodiesel may be better for the environment, the alternative fuel does have its disadvantages. First, vehicles and equipment powered by biodiesel have lower fuel economy and power. That loss of power, although small, may be problematic for heavy equipment like snowplows and bulldozers. Biodiesel can also be more expensive than regular diesel, a fact the Missouri legislature took into consideration when mandating its use.

As part of the research, Grasman, and Sundaresan Sadashivam of India, a graduate student in engineering management, contacted other states that have a state biodiesel program to determine any issues they faced with year-round use. According to the responses to the survey, quality was the issue that respondents felt was most important. Nearly all of the states that responded said that all the biodiesel they use should meet the American Society for Testing and Materials’ biodiesel standards.

Cold weather can also affect the use of the alternative fuel because biodiesel can turn into a sludge-like consistency.

“Biodiesel is heavier than regular diesel, so it tends to settle out at lower temperatures,” Grasman says. “But once it’s properly mixed, it tends to not settle out. So again, it’s a quality issue.”

Grasman is still developing his list of recommendations and plans to provide them to MoDOT by the end of September. Although securing quality biodiesel will be a primary recommendation, Grasman says other suggestions may relate to the state’s 300 biodiesel fueling points. Possible recommendations may include cleaning fuel storage tanks and placing some tanks underground.

“Improved vehicle maintenance is also important,” Grasman says. “But it’s clear that if you start with good fuel, you’re likely to have fewer problems overall.”