I like math. Always have. So this blog will be lots of numbers and may be kind of dry.
Sorry, but these things fascinate me.
Naturally, now that we are three weeks in to owning Scarlett, I wanted to do some economic comparisons. I mentioned in my last blog how the Tesla Model 3 has virtually zero recommended service needs. Over the last 21 months we owned our Passat, we spent an average of $68.50/month for service (oil changes, tune-ups, etc) and about $62.50/month for fuel (we only drive an average of 480 miles per month outside of vacations).
Today I want to talk about fuel costs. This is where the math comes in. I took an estimated 280 miles of charge (which would be from zero charge to 90%, the recommended level for day-to-day driving). Of course, we would never get down to zero charge, but this will help for our comparison.
The Passat got an average of 25 mpg, but we had to use premium gas, which cost $3.25/gallon. It was a turbo and needed the higher octane. This resulted in a per-mile cost of $0.13 for fuel. Wasn’t too bad, really, since the IRS allows a $0.57/mile reimbursement for business use as the estimated cost of ownership of a car (fuel, service, insurance, depreciation, etc). For an ICE, we found that to be pretty accurate.
With Scarlett, however, to compare apples to apples, we need to figure the cost of electricity charging per mile. This gets a little trickier, but not too bad. Remember, I like math.
We charge at home on a 32 amp, 240 volt circuit. From zero to 280 miles, it would take us about 10 hours to charge (overnight) or about 28 miles per hour. Each hour of charge uses 7.68 KW (32 amps x 240 volts = 7,680 watts) or about $0.658/hour (at our retail rate from our utility, EWEB, of $0.0857/KWh).
Have I totally confused you yet?
If not, let’s try to factor in that we have a 6KW solar electric system on our house. So, in theory, if I am able to charge on a sunny day, it would cost me only the value of the electricity I am not selling to EWEB out of my surplus (which is common on a sunny day). The rate we sell electricity to EWEB at is much lower than what we buy it for. It’s $0.0255/ KWh. This translates to $0.196/hour. NOTE: charging with solar technically isn’t free since it is lost revenue, so to speak.
Bottom line is this: electric fuel costs for Scarlett are WAY less than gasoline for the Passat. Here is the summary of our costs to travel 280 miles:
• Passat: $36.40 ($0.13/mile)
• Scarlett: $6.58 ($0.0235/mile at EWEB retail)
• Scarlett: $1.96 ($0.007/mile using solar)
Not too shabby.