MIT study concludes V2G-enabled electric commercial trucks could offer lower total operating cost than conventional diesel fleet
A new study by researchers at MIT’s Center for Transportation and Logistics (CTL), concludes that electric commercial vehicles can cost 9 to 12% less to operate than trucks powered by diesel engines when used to make deliveries on an everyday basis in big cities and when V2G (vehicle-to-grid) revenue is incorporated.
The CTL study was conducted using data collected by the international office supplier Staples, as well as ISO New England, the nonprofit firm that runs New England’s electric power grid. Using that data, the researchers modeled the costs for a fleet of 250 delivery trucks, and examined alternate scenarios in which the whole fleet used one of three kinds of motors: purely electric engines, hybrid gas-electric engines and conventional diesel engines.
Based on the Staples data, the researchers modeled what would happen if the trucks in the fleet were driven 70 miles a day for 253 work days per year, with diesel gasoline costing $4 per gallon. Trucks with internal-combustion engines averaged 10.14 miles per gallon, compared to 11.56 miles per gallon for hybrid trucks, while the electric-only trucks averaged 0.8 kilowatt-hours per mile. Staples currently has 53 all-electric trucks, manufactured by Missouri-based Smith Electric Vehicles, in use in several American cities.
The study added one new component to the projections often made by industry fleet managers—the researchers looked at what would happen if the fleets of trucks were part of a vehicle-to-grid (V2G) system in which their batteries could be plugged into the electricity grid for 12 hours overnight for regulation services. In such a setup, truck owners would be paid by utility firms for the power services they provide.
After running the numbers for various scenarios in which trucks are parked at slightly different times overnight, the MIT team found that businesses could earn roughly $900 to $1,400 per truck per year in V2G revenues in current energy markets, representing a reduction of 7 to 11% in vehicle operating costs. Firms would also save money on fuel, and on maintenance, because electric trucks induce less wear and tear on brakes.
The operational cost per mile would drop from 75 cents per mile to 68 cents per mile when V2G-enabled electric trucks are substituted for internal-combustion trucks. Jarrod Goentzel, director of the Renewable Energy Delivery Project at CTL and one of four co-authors of the new study notes, “almost all these costs scale down to the individual vehicle.” Firms do not need fleets as big as 250 trucks to realize savings.
Another of the paper’s co-authors, Clayton Siegert, a 2009 graduate of the CTL’s master’s of engineering in logistics program and a member of the Renewable Energy Delivery Project, presented the results in January at the IEEE Power and Energy Society Innovative Smart Grid Technologies Conference, in Washington. The paper will be published in a volume of the conference’s proceedings. It originated in a thesis project by two researchers who received the master’s of engineering in logistics from CTL in 2011, Andre De Los Rios and Kristen Nordstrom.
A. D. Los Rios, J. Goentzel, K. E. Nordstrom, C. W. Siegert. 2012ISGT0236, Economic Analysis of Vehicle-to-Grid (V2G)-Enabled Fleets Participating in the Regulation Service Market