EVs Don't Cost Much to Run: Page 2 of 2

But the Math is Tricky
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Inside this Article

Author with vehicle
The author with his all-electric 2012 Nissan Leaf.
Plug in the vehicle to recharge
Refueling an electric car is easy—just plug it in to recharge the batteries.
Onboard tools
Using onboard tools helps Nissan Leaf drivers plan their cars’ refueling for times when electricity rates are cheaper.
Dashboard
The dashboard also displays the vehicle’s energy use.
Electric vehicle service equipment
The hardware on the wall, known as electric vehicle service equipment (EVSE) is a networked supply of 240 V electricity. This EVSE—Blink, provided by The EV Project, monitors and transmits charging patterns to a central database. The Blink charger also has a small monitor that allows users to track charging.
PV Array
A 5.89 kW batteryless grid-tied system helps offset utility electricity use for the home and car-charging. This subsystem of nine modules sits on the carport roof.
PV System used to offset vehicle charging
In many locations, a 2.5 to 3.5 kW batteryless grid-tied PV system can provide sufficient energy to offset common EV driving patterns.
The author in his vehicle
Even if exact numbers are hard to pinpoint, the economics of driving an EV are compelling—less than half of what a 40 mpg gas car costs to fuel. An electric car’s environmental benefits and fast, smooth acceleration are icing on the cake.
Author with vehicle
Plug in the vehicle to recharge
Onboard tools
Dashboard
Electric vehicle service equipment
PV Array
PV System used to offset vehicle charging
The author in his vehicle

Solar Adds Savings

In February, my PV system produced 331 kWh that I would have otherwise had to purchase from PG&E. That represents about 85% of my EV charging for the month, which at my average per-kWh price for charging ($0.1547) would have meant another $50 of electricity. Without the PV-generated electricity, the charging cost would have been higher, since our overall electricity usage would have climbed into higher (and more expensive) tiers. In fact, the incremental cost of charging the EV would have made all of my electricity more expensive, but my PV system essentially erases that penalty.

There are so many numbers and extenuating factors and circumstances, but for the sake of argument, nearly all of my EV’s fuel costs could be considered offset by PV-generated electricity. This decreases the payback period on my PV system—just as the cheaper electricity decreases the payback period of purchasing an electric car.

The savings are greater during May’s sunny days—that’s when my PV system’s output jumped to 603 kWh (nearly double February’s production). I also stopped running my heating system, which uses a lot of electricity to power its fan. Most of May’s EV charging was during off-peak hours, which range in price from $0.03 to $0.198 per kWh. Only about 15% of the time did I succumb to charging during the peak times of 2 to 9 p.m. By the end of the month, these prices had shot up to more than $0.50 per kWh.

In May, with greater PV production, our adjusted electricity use, which factors in PV production and utility consumption, was 461 kWh. My driving in May also eased off to 341.76 kWh, down from 385.12 kWh in February. In May, the total cost for the 1,128 miles of EV driving was $47.40—an average of $0.139 per kWh.

In May, if I had exclusively charged the EV between midnight and 7 a.m., I could have reduced costs from $47.40 to $30.64. Still, the $47.40 is nearly one-third of the $113 gasoline bill I would have had fueling a 40 mpg gas car at $4 a gallon.

The PV system generated 603 kWh in May, helping charge my Leaf (which used 341.76 kWh) and offset at least one-third of my home’s electricity use during that month. Without the PV system’s contributions, the portion of my electricity usage in the higher tier would have been greater, driving up the overall cost of recharging the Leaf.

Big Picture Savings

How does all this stack up to the $0.02-per-mile value that gets tossed around? In February, my EV fuel costs were $0.047 per mile. In May, they were $0.042 per mile. That compares to about $0.10 per mile for a 40 mpg gasoline-engine car in those months.

While my cost was a little more than double the common EV claim—which says EVs cost one-sixth as much to fuel as gas-powered cars—I probably could have gotten quite close to the promise of big EV cost savings if I had charged the Leaf only in the middle of the night; driven it more efficiently; and compared it to a 30 mpg gas-powered car instead a 40 mpg one (the national average for a new passenger car is currently about 23 mpg).

But thanks to solar and electric-drive technology, even with my lead foot and a charge-when-I-want-to attitude, I’m able to cut the cost of vehicle fuel by more than half. And to me, the reduction of carbon in the environment and the displacement of oil use—from a supply chain fraught with economic and political dangers—are absolutely priceless.

Access

Bradley Berman writes about green transportation, contributing to The New York Times, KQED Public Media, PluginCars.com, and other publications. He is a research analyst for Pike Research­—a clean technology market research firm—and serves as a consultant to eBay’s Green Driving Center.

Comments (10)

Jim and Elaine Stack's picture

Rob, Thanks for the warning. I thought Chevy would be much better than that. Our LEAF and FOCUS have been perfect from day one. The few we talked with that had problems were all given loaners and the problems fixed quickly.
Sorry about you experience. Let us know if they get their act together. Maybe a Tesla Gen III in 2015 will put them all on alert and may them shape up or miss out on service.

Robert Pollock_2's picture

Jim & Elaine Stack; I just read your comments and you sound just like I did a few weeks/months ago. The Spark EV I leased 9 days ago has been back at the dealer for 6 of those 9 days. The Odometer reads 207 miles, about 40 to 60 of which I, or my wife put on the car until it was dead. It can't be charged and they don't know why. This is the second time they've had it for days, and always gave it to me with 3/4 charge showing, which in itself makes you wonder, why not full?
The manual says to keep it full, but you can't. It shows about 58 miles now, so by end of day tomorrow I'll be calling I-star again, to have it taken back to the shop. This is not funny, but Chev will not get me another car or tear up the lease on this one. Rarely would I say this about someone because I not qualified to make the judgement, but he sales people at Diamond Hills Auto Group Chevrolet are not only ignorant regarding Electric Cars, (they told me about the free oil changes) they're just plain stupid people that are through learning. Ask any one of them what OHM's law is? I learned that in school, age 14 or so. They all missed that part, and the rest.
This is funny; When the battery is dead, there is enough power to call Onstar, but during the message the car cuts off the connection to save power. Take you cell.

Robert Pollock_2's picture

Living in Palm Springs, sunshine and Electric cars seem as natural as the desert and mountains. I researched EVs for six months then decided on a Spark EV, but the 2LS with the DC Fast Charge option.
That lead me into the sleazy morass of 'business' thugs called Chevrolet. The long version, we were going to court because they lied to me about the charging options. They lied because they didn't know what it was, for one thing, and because they tell you anything you want to hear, for another.
I decided my credit rating was worth more than their car, so I capitulated and now have an obsolete EV. I will hate, and I mean hate, Chevrolet for a long time. I want to tell people about EVs and to stay away from Chevrolet, which of course is, General Motors. They sell sophisticated 21st century electric cars, but are still controlled by 20th century bait and switch and enforcer, thug like pressure tactics.

Jim and Elaine Stack's picture

All electric vehicle and even plugin hybrids and hybrids have a 8 year 100K mile warranty. So we can know that batteries will last that or twice as long.

The EV's with liquid cooling think they might last the life of the vehicle! We will see and just like solar panels the warranties will increase as they prove to last longer in the real world..

Jeff Bohnert's picture

Ok, but what about battery life, and replacement cost?
My laptop battery does well in it's first year but by the start of the 3rd year it is only at about half the capacity. Heck 1 year in on my iPhone and it's showing serious signs of storage issues.
I will say though I have a Li-ion powered 40v lawn trimmer that I quite like because I don't have to mess around with mixing fuel, changing a carb, pull starting, or listening to the noise all advantages I would be happy with in an electric car.

Robert Winfield_2's picture

for a useful graphic, the US govt collects weekly fuel prices
http://www.eia.gov/petroleum/gasdie...
They only have 1991 forward. If you graph regular gas prices, it is nearly a flat line from 1950-about 2000. If you graph from about 2001 and extend to 2021, you can eyeball a regression line showing that in about 3 years regular gas will be over $6.00 and in about 5-5.5 years be over $7.00/gallon with NO oil shocks. If you graph worldwide production of oil, you will notice the graph is getting a flat top, no matter what is done, more cannot be pumped because there is NOT more to be pumped, hence rising prices

Robert Winfield_2's picture

There are a few other positives of EV's (and PV). The ubiquity of literally billions of 120v outlets in the US that can be used to charge up.
During Superstorm Sandy, there were very long lines to get gasoline at the very few operable fossil fuel stations.
During the Derecho on the East Coast last summer, power was also knocked out, for a shorter time.
In both instances, members of EVADC managed power, one tapping off the 12v in his PHEV Prius with a 1kW inverter to have power for the refrigerator and a few lights with the PRius in ready mode to fill the 12v battery as needed from the traction battery
Several other members tapping off their Leaf's 12v with a pure sine Xantrex 1kW inverter to also power the refrigerator and a few lights. If necessary after about 3 days, the Leaf could have been driven to a 120v plug or 220v plug and the traction battery recharged.
Both instances use the main traction battery to keep the 12v battery charged. It really works
http://evadc.org/page/2/

I have a graphic but cannot paste it here

winfield100@yahoo.com

Michael Welch's picture

Hi Robert. Great info, and really good points. Specially appreciated hearing that folks have become creative with their EVs in the wake of those disaster grid failings.

rumpole's picture

Your 4.2 cents/mile is in line with my 3.5 cents/mile for my Leaf. My utility in Maryland, PEPCO, doesn't use TOU rates, so the calculation is much easier. I get the kWh data from the CARWINGS web site, which conveniently records all of my driving data, including energy usage. I spend about $50.00 per month in electricity for the car.

The comparison to an ICE vehicle should probably be made to the car the Leaf replaces, a 1998 Saturn SL2, in my case. I managed 30 mpg out of it, which worked out to 12 cents/mile. So, I have a cost reduction of a factor of about 3.5 .

As the Stacks point out, the real payoff is in what I call "cutting the nozzle". It is so liberating not to be dependent on whatever the asking price is at the pump.

Jim and Elaine Stack's picture

the real payoff is never having to stop and fuel up, just plug in while you sleep Off Peak at night. Clean, efficient the only way to travel.
Unless you can travel at the speed of light for fractions of a cent on telecommunications and fiber optics. Being there takes time and money, calling takes seconds. Video conference takes seconds.

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