Tony Crocker wrote:We just completed one month of ownership, during which we drove 2,554 miles. This included 2 trips to Mammoth and one to Santa Barbara wine country. I used 698kWh at Superchargers and 398kWh at home. The charging speed at home on the 240v NEMA 14-50 is about 26 miles/hour. The marginal cost of electricity at home is about 20 cents/kWh, so that's about $80. A "full charge zero to empty" is theoretically 90kWh or $18 at home. But I limit home charging to 70% to be conservative about prolonging battery life. And when we arrive home from a trip near empty we take the car down to the local supercharger 3 miles away late at night and put 200+ miles of charge on the battery. So the daily home charging is mostly recharging the 20-50 miles we might drive locally each day. I suspect the ~$80/month for local driving is a likely fairly stable cost going forward. The supercharging use is what will vary the most and spring will definitely be the highest Tesla travel season. Winter travel is either by air or beyond the efficient Tesla travel radius of ~400 miles.
I have also had solar panels since 2009 that cover ~3/4 of my electric bill pre-Tesla. Going forward solar should still pay a bit over half, but of course the marginal cost of 20 cents/kWh is the correct way to look at that. In terms of comparing to gasoline cost, California is well above average for the US for both gasoline and electricity, so these comparisons should be done using one's local rates.
The marginal cost of supercharging is zero, but I've read that $2,000 of the price of each Model S or X is earmarked to build out the Supercharger network. The Model 3 is described as "Supercharger enabled." I have not seen yet whether Model 3 will have "free supercharging with cost built into the car" or paid supercharging. One could argue that many Model 3 buyers would prefer a lower initial cost and pay-as-you-go supercharging, especially if the car is going to be mostly used in a radius from home and not much on extended travel. However, the existing supercharger network would need to be retrofitted to accommodate payments, and to distinguish which cars are paid vs. free.
Thanks for the info....very interesting. I'm not sure my math is right and this are "back of the envelop" calculations, but if you drove 2554 miles (in a traditional car with a combustion engine) that averaged 20 miles per gallon, you would have spent approximately $320 at $2.50 per gallon (not sure what you're paying in California for gas). If you had powered up your Tesla for all of your miles at home at .20 kWh, it would have cost you approximately $220 (1100 kWh X .20), so about one-third less? Does this correspond with your own figures?
