Fuel costs of electric cars vs. gas powered cars

by Ernie Hernandez on March 31, 2011

Dollar SignA really small sample of (real world) energy cost variance

[UPDATE] We wrote this article in 2011 as an expression of our personal experience comparing the costs of driving our gasoline powered vehicles that we owned at the time with our 2011 LEAF. We have since offered several updates that offer a more useful perspective. First – How much does it cost to drive a Nissan LEAF (found here). Second – Cost to drive a Nissan LEAF compared to a gas powered car (found here). Third – Department of Energy chimes in on cost of driving an EV (found here).

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The Hernandez family personal fleet for the past several years has consisted of a 2002 Nissan Sentra SE-R Spec V (my little toy), and a 2004 Nissan Quest SE minivan (the family truckster). Here we will provide a look into the energy cost variance in operating these vehicles given current fuel prices. This is not an attempt to determine overall cost of ownership.

First up – the Sentra. While a compact car with a 4-cylinder engine, the SE-R Spec V version is the bad boy (if such a moniker can even be applied to a Sentra) of the lineup. 175 horsepower and 180 pounds of torque would just about keep up with a 70′s muscle car in both zero-to-sixty and 1/4 mile times, while providing better fuel economy with half the cylinders. The price paid was the necessity to feed the Sentra premium gasoline. Over the nine years of possession, we racked up a grand total of just over 31,000 miles, or roughly 3,444 miles per year. The Sentra has found a new home to make way for the LEAF.

At current gasoline prices in San Diego, premium gasoline would run around $4.20 per gallon – roughly twenty cents higher than the cost of regular gasoline. If driven moderately, the Sentra would return a combined fuel economy of roughly 24 miles per gallon. Divide $4.20 per gallon by 24 miles per gallon and the result (quotient if you’re a math geek) is $0.175 per mile in gasoline cost. Now it didn’t cost us that much to drive it over the last nine years, but if we had not sold it, that is what it would cost us to drive it today. We try to look at all vehicles based on combined fuel economy, vs. city or highway. Our thinking is this – nobody lives on the highway, but most everybody uses it. Real world – everybody drives some form of combined city/highway driving. The EPA has finally recognized this, and all new cars sold since 2008 have City, Highway and Combined ratings on the window sticker. (And no… combined is not just the average of City and Highway miles per gallon. Various efficiencies (or inefficiencies) impact the combination, so it really is best to get it from the sticker).

The Quest is a different story. With its’ 3.5 liter V-6, large mass, and rectangular shape, fuel efficiency is not its’ forte. The Quest, though, can get by with regular grade gasoline. Unfortunately, the Quest’s duties included shuttling kids to school and some commuting, along with the periodic family vacation to assist in the “keeping the family sane” department. As a result, the combined fuel economy for the Quest hovers somewhere around 19 miles per gallon (and we might be slightly favoring ourselves here). In the seven years that we have been driving the Quest, it has accumulated about 90,000 miles – or roughly 12,850 miles per year. This is likely more representative of a typical vehicle owner in Southern California than our Sentra was. Divide $4.00 per gallon by 19 miles per gallon and we have $0.21 per mile in gasoline cost.

Now let’s take a look at the energy cost of the LEAF. As we mentioned previously, we are currently charging with the supplied 120 volt electric vehicle supply equipment (EVSE) using our SDG&E domestic residential (DR) rate. We admit that we are not particularly frugal in the Hernandez household and are charged the top tier of over $0.22 per kilowatt hour. This is the rate used to charge the LEAF since we got it last Friday. We are making no attempt to be refined in our discussion here, as we do not have refined numbers. Just as well, as this small sample is more for general reference than academic use. With a 24 kilowatt hour battery pack, lets say it takes 27 kilowatt hours of juice out of the wall to recharge due to some energy loss in the process. And let’s say that we are not being particularly frugal in our attempt to drive the LEAF, so we only get 75 miles out of our battery pack. This requires a little more calculation – 27 kilowatt hours of power used at $0.22 per kilowatt hour means that it would cost $5.94 to recharge the battery from empty to full. In this instance, $5.94 would move us 75 miles down the road, so $5.94 divided by 75 miles gives us an energy cost of $0.0792 per mile.

When our second meter is installed by San Diego Gas & Electric and we are placed on the electric vehicle time-of-use rate, our charge rate will drop to roughly $0.075 per kilowatt hour, for super-off peak charging between midnight and 5:00 AM. Considering that we haven’t charged at all the last two days using the supplied 120 volt EVSE, we think we’ll be able to manage that. Using the numbers from above, the cost of energy per mile drops to $0.027 per mile. Less than three cents per mile (energy cost only) to drive the LEAF vs. twenty one cents per mile (energy cost only) to drive the Quest.

We know that these numbers are fuzzy. We live in a world that isn’t always clear. We are running some numbers that apply to our situation. Your situation is very likely different. We recommend looking at your own situation if you are considering acquiring an EV.

Are electric car batteries expensive? Yes they are. Assuming stable fuel costs for the next nine years (the period of time that we owned the Sentra, and a possible lifespan for the initial battery pack), let’s take a look at the potential cost. 12,850 miles per year for the LEAF (equivalent to past mileage in the Quest) gives us energy cost alone of (12,850 miles per year times nine years times $0.027 per mile)  $3,122.55. Continuing to drive the Quest (or its equivalent) for the next nine years would cost (12,850 miles per year times nine years times $0.21 per mile) $24,286.50. Driving the LEAF provides a potential savings of over $21,000 in energy cost alone. We think that might cover the cost of the battery should we decide to keep the LEAF.

{ 6 comments… read them below or add one }

Gwido April 1, 2011 at 7:15 am

Ernie, why are you comparing the LEAF to the Quest when calculating potential savings? Will the LEAF replace the Quest and the Quest replace the Sentra you sold?
In my case, the LEAF will directly replace the car I use for commuting to work, but not the family vehicle (unless I install child seats in both cars).

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Ernie Hernandez (LEAFguy) April 2, 2011 at 12:49 pm

Gwido – good question! You described exactly what we are doing in our household. The Quest was our primary vehicle with the Sentra being our secondary vehicle. Now the LEAF will become our primary vehicle with the Quest replacing the Sentra as our secondary vehicle. I had given some thought to a follow-up article, and you have given me the reason to write one to clarify. Thanks! :)

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Varun Bhatia January 3, 2012 at 11:17 pm

funny i have a 3.5 liter VQ as my daily driver as well. 2003 Nissan Maxima which will be parked a whole lot more because of my New Leaf. :)

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Ernie Hernandez (LEAFguy) January 4, 2012 at 10:10 am

Varun – thanks for the input.

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evan Krantz May 20, 2013 at 9:08 am

Well to be honest the thoery is fundamentally flawed. The overall cost of repair and savings ratio is not even close to good for electric, not mention range and rate of charge and time involved vs rate of discharge in the real world. Battery relpacement alone more than covers any intial savings by huge long cost savings. now take into account repairs, gas engines are easy to fix, parts are cheap and they last up to 300,000 depending on who built the car with little or no fixes. Most states have a monopoly on electric companies and there is only one provider. Take into account that also state electric caps are being removed, now the rate will increase due to demand and the grid being outdated nationwide, in PA alone electric rates have gone up 3 seperate times in 2012, less use of coal in producing electric and the wide testing and use of extremely dangerous fraking for the environment. all this so someone can artificially feel good about so called no emmisions..when reports have already shown that building even hybrids and electrics is more dangerous to the environment than building a gas powered car before even driving…the sentra would get mid to high 30s in mpg with high flow cat, intake, tune, and rerouted mandrell bent exhaust but we snorkel our engines for the sake of drive by noise constraints.

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Ernie Hernandez (LEAFguy) May 21, 2013 at 6:40 pm

Mr. Krantz – Welcome to Living LEAF.

Referencing your statement that battery replacement would outweigh long-term cost savings, that is easily mitigated by leasing the vehicle. Battery replacement then becomes the concern of the manufacturer. Though I’m not a fan of leasing vehicles generally, with an electric vehicle and their current state of development and potential for future improvement, leasing is the wiser economic choice. Regarding repair costs of gasoline engines and electric motors – a gasoline engine consists of hundreds of parts, oil and coolant seals subject to degradation and leaking, high heat and vibration. An electric motor has none of those features and its moving parts consist of a rotor, and bearings. Think of all the electric motors (your refrigerator, for instance) that have run for years without any maintenance at all. In another article that I wrote (found here) it can be seen that since since 2002 gasoline prices have risen over 300 percent while electricity costs have risen less than 50 percent during the same time frame. It is likely that ten years from now the rise in the price of gas will have again outpaced the rise in the cost of electricity as gasoline demand increases in other parts of the world with increasing automobile ownership in developing countries. Finally, with over 70 percent of coal-fired plants now over 30 years old according to the US Energy Information Administration (EIA) (found here), these plants are reaching the end of their useful life of 40 years or so. The expectation is that replacement plants will be be natural gas, wind and solar driven to meet more stringent emissions regulations. Regarding EV range issues, a recent study (found here) shows that EV ownership is rapidly gaining ground in California as EV owners drive only 29 miles each day – well within the range of current technology. The survey reported that 92 percent of owners rated the experience satisfying overall. My long-held position has been as follows: an electric vehicle is not right for everyone, but if it’s right for you, you will be very pleased with your ownership experience.

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