Useful eGallon tool on Department of Energy website. Here's my state, Nevada. Almost two thirds of our electricity is produced by natural gas. eGallon | Department of Energy

For those that are interested in a detailed explaination of eGallon methodology, here you go: https://www.energy.gov/sites/prod/files/2016/01/f28/eGallon%20methodology%20%28Updated%20January%202016%29.pdf

Interesting. But they must be using average gasser vs average BEV number to come up with the difference in cost. Unfortunately, if you compare HV vs EV on PRIME, the number is not as optimistic as shown on this site for some states. For me, HV and EV cost/mile are currently dead even to slightly more on EV.

That could be true compared to the state average. But it attribute more to the PRIME's efficiency on HV mode. Average gasser they used to calculate the number is probably 25-30mpg. But as I and you know very well, PRIME is capable of getting 54 mpg EPA rating on gas alone, and if you drive conservatively, it can easily get over 60mpg closer to 70mpg. Even the best BEV on market is around 4.5miles/kWh EPA. Average likely to be lower than that.

From the linked doc on eGallon: For instance, if the average 2015 passenger car adjusted combined fuel economy, mi/gal is 27.9 mi/gal and the average efficiency for the top selling U.S. EV brands in 2015 is .326 kWh/mi, the price of an eGallon would be: 27.9 mi/gal * .326 kWh/mi * .1269 $/kWh = $1.15/gal Now, you do the same calculation but substitute the PRIME (or Gen4 Prius) as a gasser on HV mode for 54mi/gal and use the US EV brands average .326kWh/mi (BTW this is equal to 3.06miles/kWh), and my current residential electricity cost of .195 $/kWh 54.0 mi/gal * .326 kWh/mi * .195 $/kWh = $3.43/gal Current gas price around my area is $2.45/gal. eGallon cost is quite bit higher than actual gas Gallon. If I do this calculation with the real life numbers on my PRIME using 65mpg and 4.5miles/kWh (=0.222 kWh/mi) 65.0 mi/gal * .222 kWh/mi * .195 $/kWh = $2.81/gal eGallon cost is still higher than actual gas Gallon.

You can’t take a generalized statistic and fault it for not being the same numbers you get for your personal transportation. If you drive more efficiently on gas, you will get better than average annual fuel costs. That doesn’t mean the car sticker that shows the annual fuel expense is useless. It, like the MPGe stat is a valuable baseline.