CAMBRIDGE, MA - Using electric vehicles (EVs) can markedly lower the costs of a fleet of delivery trucks, according to a new Massachusetts Institute of Technology (MIT) study. The study shows that EVs are not just environmentally friendly, but also have a potential economic upside for many kinds of businesses.

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, researchers at MIT's Center for Transportation and Logistics (CTL) found that EVs can cost 9-12% less to operate than trucks powered by diesel engines, when used to make deliveries on an everyday basis in big cities.

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 diesel gasoline cost $4 per gallon. Trucks with internal-combustion engines averaged 10.14 miles per gallon, compared to 11.56 mpg for hybrid trucks, while the electric-only trucks averaged 0.8 kilowatt-hours per mile. Staples currently operates 53 all-electric trucks, manufactured by Mo.-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, as an additional resource for providing reliable electricity to consumers. In such a setup, truck owners would be paid by utility firms for the power services they provide. V2G systems are currently being tested by multiple utility companies.

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 7-11% in vehicle operating costs. Firms would also save money on fuel, and on maintenance, because electric trucks induce less wear and tear on brakes.

All told, the operational cost per mile — the basic metric all fleet managers use — would drop from 75 cents per mile to 68 cents per mile when V2G-enabled electric trucks are substituted for internal-combustion trucks, based on the MIT findings.