For most car buyers, the MPG of a car is a huge influence on whether or not they will purchase it. It helps you understand how often you’ll need to fill up, and therefore how much you’ll spend on gas each month. When it comes to electric vehicles, however, miles per gallon doesn’t apply. So the EPA established MPGe, or miles per gallon equivalent, to help consumers understand EV efficiency.
Just like miles per gallon, MPGe is the potential distance per unit of energy consumed. But instead of the energy being gallons of gasoline, it is the amount of electricity in kilowatt-hours (kWh). The EPA determined how much electrical energy is in one gallon of gasoline– about 33.7 kWh. The distance the car can travel on that amount of energy is the MPGe. So a higher MPGe means the car can go farther using the same amount of energy.
Looking at the Numbers
According to the Department of Energy, the average passenger car gets 27.9 MPG and the average gas price in MD is $1.75. Therefore, we can calculate the average cost per mile is $0.06. In contrast, the average cost of residential electricity in MD is $0.1269 per kWh and the average efficiency of the top 5 most popular EVs is 0.326 kWh per mile. This results in a per mile cost of $0.04, which is 33% less expensive.
The FHWA reports that the average licensed driver drives 14,834 miles per year. This results in a fuel cost of $890.04 versus $593.36 for EVs. This means you’ll save $297 per year in fuel alone by switching to electric. And gasoline is inexpensive right now, but the price could increase dramatically over the next few years. The cost of electricity has been stable for the past decade and a half. You can see the cost of gasoline versus the cost of the equivalent amount of electric energy in this chart from the DOE:
If you want to compare between EVs, look for “kWh per 100 miles” on the official label (see below). This tells you the efficiency of the car by the amount of energy it takes to travel 100 miles. This is a linear comparison of one EV to another, so a higher number is best.