The first three months of my Volt Ownership ended yesterday. When I parked the car last night, it had a total of 4,787 miles on it. Of those, 3647 were driven without gasoline. It had 189 miles on it, when I bought it, but I do not know if those were electric, gas, or a combination. I’m going to bet the dealership kept it charged so that people test driving would get the full Volt experience. Therefore, my breakdown is roughly like this:
3,458 miles on battery, or 75.2%
1,140 miles on gasoline, or 24.8%
4,598 total miles driven by me.
The first number that jumps out at me is total miles. My lease is set up for 15,000 miles per year. At this rate, I will end up putting 18,392 miles on per year. NOT good. I’ll have to keep an eye on that.
The price of gas has dropped recently, so using the “Cheap Gas!” app, the cheapest gas in my area is $3.07 for regular and $3.37 for premium.
My electric utility charges me $0.10725 per kilowatt hour (kWH), and I have averaged 4.1 miles per kWH, over the time period I have been keeping a spreadsheet to track this. (October 8th to November 3rd). That is a bit skewed, because it has cooled down a lot since August, when I first bought the Volt. On hot days, I almost always could take my daughter to school and drive to work and back home on a charge, usually having 1 mile of charge left as I pulled into the garage. that was 43 miles in all, so:
43 miles / 12 kWH = 3.58 miles per kWH during August & September
We’ll use 3.58 for those two months (estimated) and 4.1 for October, where I have actual data on each drive.
(August + September + October) / 3 = Average MPkWH over the three months (estimated). or:
(3.58 + 3.58 + 4.1) / 3 = 3.76 MPkWH <Volt>
As I’ve mentioned before, my previous car, a 1999 Lexus ES300 got 22 miles per gallon. Unlike the Volt, it ran on regular gas. Therefore, if I had driven the same distance in my Lexus, it would have used 209 gallons of regular gas:
4,598 miles / 22 MPG = 209 gallons <Lexus>
At today’s price, which, as I said has fallen lately, (regular gas was $3.55 when I bought the Volt, $3.07 today), my fuel cost would have been:
$3.07 X 209 gallons = $641.63. <Lexus>
The Volt is a combination of electric- and gas-powered miles as follows:
3,458 electric miles / 3.76 MPkWH = 919.68 kWH <Volt>
Multiply the kilowatt hours bay the price per kilowatt hour to get total cost of electricity used:
919.68 kWH X $0.10725 = $98.64 <Volt>
On top of this is the gasoline used. I have been averaging 37 MPG, so:
Total gas miles / MPG = gallons of gas used:
1,140 miles / 37 MPG = 30.81 gallons. <Volt> (I actually think this number is high, since I’ve only bought three tanks of gas, and I still have about a third of a tank in the Volt now)
The gasoline used by the Volt is premium grade, which is currently $3.37 in my area. So:
gallons used X $3.37 = total cost of gasoline burned or:
30.81 X $3.37 = $103.83 <Volt>
Total fuels cost, for the Volt, electric and gasoline is:
$98.64 + $103.83 = $202.47 <Volt>
This is a savings of $439.16 !
This is an average monthly savings of $146.39, versus the fuel cost of my Lexus ES300.
My Volt lease payment is $330.07, so effectively, my monthly total cost of ownership for the Volt has been:
$330.07 (lease) – $146.39 (fuel savings) = $183.68 per month!
My original estimate of the increased expenditure associated with the Volt was $198.49, so I am quite pleased with the results. I also believe this is a conservative estimate and during most of the last three months gasoline prices were considerable higher, so the financial advantage was greater than my estimate today.
Going forward, the Blink Level 2 chargers we installed will give me actual electricity costs associated with each charge. Because they charge the battery in about 40% of the time the stock charger took, some of the miles I have driven using gasoline will now be able to be driven using electricity. In other words, if I start charging as soon as I get home. within one hour, I’ll have 10 additional miles I can travel on electricity. Because of this, I expect my electric to gasoline ratio to be even more biased toward electricity. Hopefully, I’ll see that 75% go up…
Now, for one last calculation. What is my actual Miles Per Gallon Equivalent (MPGe)?
Gasoline miles per gallon = 37 MPG. We already know this, from the work above. I had this MPG for 24.8% of the miles I have driven.
Electric cost was $98.64 to go 3,458 miles, so the cost per mile was:
$98.64 / 3,458 miles = $0.02853 per mile.
Premium gasoline costs $3.37 per gallon, so:
$3.37 / $0.02853 = 118.14 miles per gallon equivalent, when running on electricity. I did this 75.2% of the miles driven.
To calculate average MPGe then:
( 37 MPG X 24.8% ) + (118.14 MPGe X 75.2% ) = 98 MPGe !
I believe this is a more accurate way of calculating the MPGe than what is shown on the OnStar RemoteLink app, since it takes into account the relative cost of electricity and premium gasoline.
This figure is during a very hot Texas Summer, and I am more focused on my driving style and using the efficiency tools of the Volt, so I believe at the one year mark, my MPGe will be higher.
