Comparing Energy Costs per Mile for Electric and Gasoline Vehicles

The fuel cost of driving an electric vehicle depends on the cost of electricity per kilowatt-hour (kWh) and the energy efficiency of the vehicle. For example, to determine the energy cost per mile of an electric vehicle, select the location on the left axis (Electricity Cost per kWh) at $0.09 in the graph below. Draw a horizontal line to the right until you bisect the EV 3 mile/kWh line. Now draw a vertical line down until you bisect the bottom axis (Energy Cost per Mile). This tells you that the fuel for an electric vehicle with an energy efficiency of 3 mile/kWh costs about $0.03/mile when electricity costs $0.09/kWh.

Cost of Electricity vs Gasoline as Vehicle Fuel: If electricity cost per kilowattt-hour is 9 cents, the energy cost per mile is as follows: 2 mi/kWh = 4.5 cents; 3 mi/kWh = 3 cents; 4 mi/kWh) = 2.25 cents. For gasoline at $2.50 per gallon, the energy cost per mile for a vehicle that gets 22 miles per gallon is 11.4 cents. For a vehicle with 18 mpg, it is 13.9 cents.

The national average cost for electricity in the United States is about $0.075/kWh, while the average residential rate is about $0.089/kWh. Some electric utilities have had electric vehicle charging rates that vary by time of use, day, and season. These rates can range from $0.03 to $0.50/kWh. Older electric vehicles have energy efficiencies of about 2 mile/kWh. Some electric vehicles, such as the EV1 from General Motors, had energy efficiencies of over 6 mile/kWh.

To determine the energy cost per mile of a gasoline vehicle, pick the location on the right axis (Gasoline Cost per gallon) at $2.50. Draw a horizontal line to the left until you bisect the Gas 18 mile/gal line. Now draw a vertical line down until you bisect the bottom axis (Energy Cost per Mile). This tells you that the fuel for a gasoline vehicle with an energy efficiency of 18 mile/gal costs about $0.139/mile when gasoline costs $2.50/gallon.

The mileage for commercial fleet vehicles, such as light-duty pickups, ranges from below 17 to about 22 mile/gal. The energy cost per mile is also included for a hybrid electric vehicle with an energy efficiency of 40 mile/gal, as these types of vehicles are increasingly being used.