Cost of Electric vs Cost of Gas - where is the break even point

The recent rise in the cost of gas had me look at this sort of question again, but from a bit different angle, that is for figuring out when to buy kWh at charging stations when away from home. I'm in $.10/kWh Washington state for home charging, and use 4 mi/kWh on EV and 55 mi/gal on HV for calculations. Back (well, not that far back) when gas was less than $3/gal, I eschewed the stations that cost $.25/kWh or more. It works out that away from home charging at $.25/kWh (what lots of Chargepoint spots cost) works out to about the same as $3.40/gal. So where I used to pass these up, I now will use them vs. >$5/gal gas costs if I'm not going to get home without running out of my EV battery. I'm even willing to pay up to nearly $.40/kWh as gas passes the $5 mark.

 

Your break-even point is $0.396 kWh. The assumptions are $5.50/gallon, 50 mpg, and 4.0 miles/kWh. The numbers and math are skewed in our favor, because EV mileage may vary greatly depending on driving conditions. Right now, I'm averaging mid to high 4 miles/kWh, but this last winter I was only getting mid to high 3 miles/kWh - and we have very mild winters here.
So if your total electricity cost is less than 40 cents/kWh and you need to do something else while the car is charging - it's worth plugging-in otherwise just run it on gas......

 

For those interested in determining their own breakeven points using their own cost and mileage estimates, the math is straightforward:
Find electricity rate given pump price: $/kWh = $/gal * m/kWh / mi/gal.
Find pump cost given electricity rate: $/gal = $/kWh * mi/gal / mi/kWh