The mix of fuels used to power the vehicles on our nation’s roadways is diversifying rapidly. While gasoline and diesel are still dominant, an increasing percentage of vehicle power is coming from alternatives such as biofuel, natural gas, and electricity. What could this shift mean for Minnesota’s transportation future? The Minnesota Department of Transportation and the Minnesota Local Road Research Board turned to U of M experts for analysis.
“The rise of alternative fuels is something we need to keep a close eye on, because it presents a number of issues that may significantly alter our state’s transportation system,” says Adam Boies, an assistant professor in the Department of Civil, Environmental, and Geo- Engineering (CEGE).
Minnesota leads the nation in biofuel use, in part due to a series of legislative acts designed to encourage ethanol production and consumption. Boies predicts, however, that biofuel consumption in the state is near saturation and that future shifts will likely be between biofuels.
If the price of natural gas remains significantly lower than diesel fuel, natural gas vehicles will likely make up an increasing share of the heavy-duty vehicle fleet in Minnesota. A larger natural gas refueling infrastructure will need to be developed, most likely by private organizations that manage fleets of vehicles.
Minnesota electric vehicle sales have lagged behind the nation—winter temperatures are one factor—but Boies expects the numbers to rise. He estimates 16 percent of new cars sold in Minnesota in 2035, and 56 percent in 2050, will be electrified. The growing numbers will require a more robust charging infrastructure.
In the long term, on-road charging systems are being investigated. In these systems, under study in several countries, charging coils embedded within the roadway transfer power wirelessly to vehicles. “The systems could make electric vehicles drastically more efficient by reducing vehicle battery size,” he says.
Better vehicle efficiency is likely to continue the trend of falling fuel tax revenues. “Minnesota will need a method for producing revenues from electric vehicles to maintain long-term funding for the transportation road network,” he says. “Currently the higher price of electric vehicles results in increased revenues during vehicle registration, which tends to offset the difference in fuel tax revenues. However, as the price differential between electric vehicles and traditional vehicles shrinks, there will be decreased funding for Minnesota roadways unless additional revenue sources are found.”
Finally, emphasis on fuel efficiency in the light-duty and heavy-duty vehicle fleets will drive the weight of these vehicle segments in opposite directions. “Light-duty vehicles will get lighter and heavy-duty vehicle fleet operators will lobby for increased weight limits on Minnesota roadways to reduce the energy intensity of goods deliveries,” Boies says. “This growing disparity in weight between the two vehicle classes may require increased safety measures to reduce the severity of crashes between vehicle classes.”
Boies’s research is part of a multi-pronged study funded by MnDOT and the LRRB that analyzed the technological shifts altering surface transportation and the implications for Minnesota. The study was led by CEGE professor David Levinson.