Our latest video talks a little about how you can charge up your EV for 85 cents per “eGallon” equivalent. Here are the numbers behind that figure, courtesy of James Campbell:

eGallon makes its determination by multiplying 3 factors: 1) EV efficiency expressed in kwh per mile 2) average retail electricity rates (either by state or region) 3) an adjusted comparable fuel economy, Miles per Gallon or MPG.

The $0.85 a gallon was calculated using the following assumptions: the EV gets 0.34 kwh per mile (older Leaf), average residential rate of 10 cents per kwh (even though Energy Information Administration has Utah retail average as 8.72 cents/kwh), a proxy gas vehicle efficiency of 25 miles per gallon (which is roughly the average MPG for vehicles sold— 24.7 in 2016 and 25.2 in 2017), the calculation is the following: 0.34 kwh/mi x $0.10/kwh x 25 mi/gallon = $0.85/gallon

eGallon has previously used a proxy MPGe 28.2 mi/gallon instead of 25 mi/gallon and a less efficient vehicle of 0.35 kwh/mi. I believe that was based on 2012 data. Also, EV efficiency in newer models has significantly improved-I used the old Leaf’s efficiency where the most efficient EV in 2018 is Hyundai’s Ioniq 0.247 kwh/mi (Tesla’s Model 3 is a close 2nd with 0.259 kwh/mi and then it’s the Chevy Bolt 0.283 kwh/mi ).

In terms of electricity prices the highest residential price is 14.45 cents/kwh for large monthly users of over 1000 kwh per month (an EV going 10,000 miles/year only uses 3400 kwh for the entire year) probably a larger home with central AC (smaller users pay a lower rate). The lowest possible electricity price for an EV would be someone who signs up for the time of use rate and charges the vehicle after 8:00 pm, in which they pay only 3.4 cents per kwh. So the worst calculation using the highest electricity price of 14.45 cents/kwh, the worst vehicle efficiency 0.35 kwh/mi, and a high proxy MPG 28.2 mi/gallon gets an EV price of $1.42/ gallon. However, if you compare that to using the time of use rate of 3.4 cents per kwh, the higher efficient EV (Hyundai Ioniq) 0.247 kwh/mi and 2016’s average 25 MPG one gets $0.21/gallon.

Since the range of costs are between $1.42/gallon and $0.21/gallon this gives an average of $0.82/gallon depending on your assumptions. I used $0.85/gallon because it was a simpler calculation. These are all estimates with assumptions that could reasonably change. The actual fuel costs depends on the vehicle and how you drive but one thing that is absolutely true, the cost of fuel for an EV is significantly less than the cost of fuel for a gas or diesel vehicle. If you own an EV, travel 10,000 miles in a year, use the time of use rate and charge at home, you will only pay $117 for the entire year to charge the vehicle.