DOE’s Estimated Cost of Fueling an EV–A Comparison

By Paul Gipe

In Top 3 Advantages of EVs, an article on Cleantechnica, Johnna Crider cites DOE’s Saving on Fuel and Vehicle Costs web page for some numbers on how it’s cheaper to driver an electric car than a gasser. The web page includes a handy fuel-cost calculator.

Since I’d posted an article on this topic a few weeks ago, What does it Cost per Mile to Drive an Electric Vehicle?, I thought I’d check whether our approaches alligned, and if not, how they diverged.

DOE calculated the equivalent cost of an “eGallon” of electricity and compared that to the cost of a gallon of gasoline. In contrast, I calculated the cost per mile to drive an EV in comparison to that of a gasser.

For California, DOE estimates that the cost of fueling an EV is only 40% of that of the gasoline for a conventional car. This is about what I found as well. In the text of my article, I wrote that “fueling our Bolt EV costs half that of fueling a gasser at the national average fuel efficiency.”

More specifically, I found that it cost us about $0.07/mi on average to drive our Chevy Bolt both around town here in Bakersfield and on intercity trips where we, of necessity, charge our car at commercial fast charging stations.

At the national fleet average of 25 mpg for gassers, and at the price of gasoline provided by DOE’s calculator for California, the cost of fuel to drive a gasser is about @0.14/mi.

DOE only considered charging the EV at home on residential electricity rates. They didn’t include any provision for a portion of the electricity to be provided by more expensive commercial DC fast charging dispensers on the road. My calculations did.

Some 10% of the electricity we used to charge our car last year was provided by fast chargers at costs from $0.10-$0.17 per mile–significantly more than charging at home.

If I had excluded the cost of charging on intercity trips in my estimate, my calculations would have matched that provided by DOE’s “eGallon” calculator. I estimated that it cost us $0.06/mi to drive when charging only at home. That’s 43% of the cost of driving on gasoline, versus that from DOE’s calculator of 40% for California conditions.