Al Sherman
It's about THIS car.
157 miles/1.2 gallons = 130.8 MPG
So, a gas car would have to get 130.8 MPG (or 1.8 liters/100 km) to cost the same as the Model S in this scenario.
This is how I look at it. It's really the same as cents per mile. At 3.3 cents per mile assuming 4 bucks per gallon of gas (it's actually higher here now) I get 122 mpg.