Computing the Savings of Driving an All-Electric

leafI just reached 1,000 miles on my Nissan Leaf. I blogged about (and bragged about, too, I suppose) buying the Leaf in early July. Well, after having it in the body shop for a month after being rear-ended two weeks into ownership, I finally crossed the 1,000 mile threshold this morning.

The verdict? I couldn’t be happier with this car. It is a tech enthusiast’s dream. Little things like keyless entry and push-button start free me from ever having to take my keys out of my pocket. Convenience features like the bluetooth link to my phone, turn-by-turn navigation with a map that includes the location of charging stations, voice recognition that enables it to dial people on my behalf, the full-perimeter camera system that makes parking a cinch, and the steering-wheel-mounted controls for the radio are very helpful and remind me why Computer Scientists, who get to develop stuff like this, have such cool jobs. And, speaking of the radio, the special energy-conserving Bose sound system pumps out the best quality sound I’ve heard in a car.

Then there’s the drive train. Electric cars do not use a transmission to shift gears. The interface between pedal and motor speed is direct. The result is that you never feel a transmission shift. The ride is smooth at all speeds. More impressive is the acceleration, particularly when I take it off ECO mode. I’ve never driven a car that caused my head to jerk back before, so I’ve come to think of this as the midlife crisis car I didn’t know I needed.

Unlike other midlife crisis cars, though, this thing is quiet, sometimes eerily so. I’ve started to leave the car without turning it off several times since I bought it, only to be reminded with a persistent beep that I’m about to do something dumb. I’ve heard people outside the car remark (after all, I can hear them pretty easily) that they can’t believe how quiet the car is. It’s easy for the car to be quiet when it’s not being propelled by exploding gas.

But here’s what I like most about the car. This part involves a little easy math.

I drove 1,000 miles. The car’s computer reports achieving 4.6 miles per kilowatt-hour (KWh). So, the car has consumed 1000 miles / (4.6 miles / KWh) = 217.39 KWh of electricity. Electricity in this region costs about 11.7 cents per KWh. So, to drive 1,000 miles, I’ve spent 217.39 KWh * $0.117 / KWh = $25.43.

My previous car could go 22 miles per gallon of gas. To go 1,000 miles in that car, I needed 45.45 gallons of gas. Let’s assume that gas averages around $4 per gallon. (Sometimes it’s more; sometimes it’s less. I’ve actually stopped paying attention!)  To go 1,000 miles in my previous car, therefore, I would spend 45.45 gallons * $4 / gallon = $181.80.

By driving an all-electric car, I saved $181.80 – $25.43 = $156.37 over the first 1,000 miles. At this rate, if I drive 12,000 miles in one year, I’ll save 12 * $156.37 = $1,876.44 over the course of the year, plus about $120.00 in oil changes I no longer need.

In other words, in just one year, I’ll save $2,000.

Never has math looked so appealing! My costs will probably go up when the power system gets less efficient in winter and I have to turn the heated seats on to keep warm. However, I’ll still be saving a significant sum of money.

Plus, I’ll now have extra money to pay the chiropractor. After all, that frequent neck-snapping acceleration and my involuntary head-banging to AC/DC’s “Back in Black” playing through the Bose are bound to take their toll.

 

Ray Klump

About Ray Klump

Professor and chair of Mathematics and Computer Science Director, Master of Science in Information Security Lewis University http://online.lewisu.edu/ms-information-security.asp, http://online.lewisu.edu/resource/engineering-technology/articles.asp, http://cs.lewisu.edu. You can find him on Google+.

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