I think 100,000 vehicles paying for Supercharging is on the high side for this year. Perhaps the amount for the fourth quarter will be average around 75,000.
Assumptions made: National weighted average of price per kWh (skewed to California's 26 cents) = 20 cents per kWh. Half the Model 3s will Supercharge 2x/week taking 50kWh each time. The other half of the Model 3s will Supercharge once per month and take 60kWh.
Lots of owners charge at home or work and will not avail themselves of Supercharging except on a weekend trip or holiday vacation. And some folks like us just do not drive more than 80 miles per week most of the year.
37,500(2)(13)(50)(.2) = $9,750,000
37,500(3)(60)(.2) = $1,350,000
Total for the fourth quarter = $11,100,000.
Better than a poke in the eye with a sharp stick, but not very material to Tesla's overall position. Even doubling the usage only generates $22 million in revenue.