Not to resurrect a dead thread (I just don't come on to post very often) but I hate leaving questions unanswered.

I did an initial "cost to charge" comparison on annual, 5, 10, and 15y basis. There are several great websites that I found at the time, though I can't remember the exact website addresses now. (I just found them on google when doing research on evs.) There was a really good .gov website with a few tools- afdc (alternative fuels data center) something or other, but I'm not positive.

It's easy enough to calculate if you take the energy data from your vehicle in Watt hours/mile, the number of miles you drive over a set time period and multiply by your local electric energy rate. The energy rate is quite variable depending on your state, just like gas prices, although they don't fluctuate as much during the year. Evs thus make more economic sense in some locations than others. Similarly, some areas offer big price brakes for off hour energy use which makes the cost per charge even cheaper if you set your car to charge at these times.

I think my estimate was around $300 annually, so I was looking at about 25 a month if I charged 100% of the time at home. We have not noticed a significant change in our energy bill, so I have not bothered to do an actual calculation. I do know that my credit card bill has gone down several hundred dollars a month since I am no longer paying for gas.

15k annual with my prior 22mpg vehicle @ 3.50 per gal= ~2400
15k annual with my Tesla ~300
Savings ~ 2100 /yr
You can see how the savings can become significant over a 10-15 year time period. The more the use, the greater the cost savings- my wife and I used to put about equal miles on both of our cars, but are now consciously driving the Tesla- not only because it is more fun- but because by driving it we are now cutting into her gas bill as well, making the TCO of our vehicles that much cheaper over time.

Sorry such a long message. Wish I could find my initial spreadsheets, they were eye opening.