Starting May 1, Minnesota will become the first state in the nation to require buses, trucks and other diesel vehicles to fill up on a 5 percent biodiesel blend. But with even higher biodiesel requirements on the horizon, some are calling for the state to do more testing.
Since 2005, the state has required a mix of regular diesel and 2 percent biodiesel -- nonpetroleum-based fuel usually made from soybean oil. Advocates say biodiesel burns cleaner than regular diesel and is a renewable energy.
Under a measure passed last year, the required biodiesel blends will bump up to 10 percent in 2012 and 20 percent in 2015, but those will be in effect for only seven months out of the year.
That's because biodiesel has a higher freezing point, causing it to turn to gel more easily on extremely cold days. Some critics argue that as the biodiesel concentrations increase, the fuel will cause engines to stall during Minnesota's cold winters, shutting down diesel engine operators across the state.
A state task force, organized by Gov. Tim Pawlenty in 2003 to help carry out the biodiesel mandate, reported to legislators in February that the increase to 5 percent biodiesel shouldn't cause engine problems but that "there are significant issues to be addressed" concerning the increases in 2012 and 2015.
Last winter, Bloomington school officials blamed biodiesel when buses stalled in subzero weather, but later state officials said fuel filters, not biodiesel, were at fault.
John Hausladen, president of Minnesota Trucking Association and a member of the state task force, said he's not too worried about the 5 percent increase, but he is worried about the fuel price fluctuations and future increases in biodiesel concentration.
And even though the mandates will be eased during the coldest winter months, Hausladen said he still thinks there needs to be more performance testing on biodiesel.