A Tesla in Calif. is no real big savings, when you have $0.32 kWh electric rate, and just using 48amps @ 240V (Tesla home charger) is the same as running FIVE 5 ton Air conditioners at the same time
At 4 miles per kwh that is $.08 per mile in energy costs.
At $4.50 a gallon and averaging 30 MPG that would be $.15 per mile in energy costs. The Tesla will be about 40% less in per mile energy cost. I think that is significant.