Volt owners respond

Posted on 04/16/2012 by Ken Paulman

Last week, I pointed out the New York Times relied on some highly questionable calculations to determine that it would take you more than 26 years to make up the difference in gas savings if you bought a Chevy Volt over a Chevy Cruze. The post has drawn a lot of interest, both here and on The Energy Collective website, as well as some reactions from people who actually own Chevy Volts.

Matty G., for instance, points out that if you drive a lot in stop-and-go traffic, the savings from an electric car are even greater (EVs don’t use any energy when stopped except to keep the radio and other accessories on):

The equation changes substantially if you do exclusively city driving. The figure given for the Cruze is the mixed number. I, on the other hand, commute 20 miles roundtrip each day in hardcore city driving conditions; stoplights, traffic, and lots of stop-and-go. In C&D’s Volt vs Cruze Eco comparison test, they got a city mpg figure of 20 for the Cruze.

Even at $4 gas, this reduces the payback period to 8.6 years. If my commute was the 35 mile EV sweet spot, payback period would be 5.2 years.

“Dr. Innovation” says the mpg range from fuelly.com that I referenced is too limited (I agree), and also notes that his most recent tank of gas lasted for six months:

A few points.. the Fuelly data is misleading because it will NOT accept or compute data for anything above 200mpg. I’m the 168 and that is only because my first months had more long trips and so were , 200. My most recent tank (Oct-April) was over 400 MPG and fuelly will not show it. … Much better place for volt data is voltstats.net With over 800 drivers (so about 10% of all volt owners) there are only 7 with < 46.7 average MPG. The fleet average is about 120MPG computed over nearly 5 million miles. It's better than EPA because the drivers are averaging more miles on EV than the EPA predictions.

My most recent tank, from 10/29/11 to 4/13 has was 3698 mi on 8.3 Gallons of Premium + 1037kWh of wind power. With total fuel costs of $91.32 that translates to 95.23 overall MPGe, 444 MPG and 40.49 MPF$ or $.0246/mi. Compared to a Lexus hs 200h, .09/mile, my payback was instantaneous and I'm saving 1000s per year. Compared to a BMW 3series, my payback is already past.

Compared to a Cruze it is not computable as I would never buy one.

Jim Hopf also says the Volt/Cruze comparison isn’t apples-to-apples:

Comparisons of the Volt to the Cruze are just (right wing) nonsense. The two are not the same. The Volt is a much nicer car, loaded with several luxury features that the Cruze does not have. Also superior performance (handling and acceleration). A Volt with an ordinary gasoline engine would cost at least ~$25,000.

…

The real point, missed by the article, is that we first adopters are not looking for the car to pay for itself in the strict economic sense. We realize that we will not break even. The point is to support the technology and drive tech advancements and cost reductions so that it will eventually make sense. A factor of three drop in battery costs over the next decade is predicted. At 1/3 the cost difference, the car will clearly make pure economic sense.

So while some of the distorted media narratives surrounding the Volt may be puzzling to me, a mere energy journalist with a working knowledge of high-school algebra, they seem to be endlessly baffling to the people who actually own and have day-to-day experience with the car. It’s good to hear from them.

Photo by marada via Creative Commons

Is the Chevy Volt’s payback period really 26 years?

Posted on 04/05/2012 by Ken Paulman

The Chevy Volt is much more affordable if you strip it of a few options. (Photo by Wired via Creative Commons)

An article in today’s New York Times looks at different types of hybrid and fuel-efficient cars, arguing that many buyers opting for the more efficient models may take years to see any actual savings.

The article comes with a handy chart, using data from TrueCar. The chart compares the price differences between comparable conventional and hybrid cars, and using a figure of $3.85 per gallon and 15,000 miles driver per year, estimates the number of years it would take to recover the cost difference in gas savings (assuming the price of gas never goes up or down).

For most of the cars TrueCar looks at, the break-even point is ten years or less, well within the typical lifespan of most new cars. But there are two outliers – the Ford Fiesta vs. the Fiesta SFE and the Chevy Volt vs. the Chevy Cruze, both with payback periods in excess of – are you ready? – 26 years.

At this point, if you’re Rush Limbaugh, you’ll be rushing off to the microphone to declare the Volt a waste of money. The rest of you may be wondering if that number is really accurate.

The missing mpg figure

The figures for the Fiesta are pretty clear (and trivial, the cost difference is only a few hundred dollars), but for the Volt, we’re left with a mysterious dash where there ought to be a data point – the assumed mpg.

Working backwards using a spreadsheet, I found that the missing number is 46.7 – that would be the mpg equivalent you would have to achieve with a Volt in order to reach a payback period of 26 years. That seems a tad pessimistic, considering the EPA rates the car at 93 mpg equivalent in electric mode and 37 mpg running on gasoline.

The problem with pinning down a mileage figure for the Volt is that it depends entirely on how much you drive in electric mode. A person driving fewer than 35 miles per day (the Volt’s approximate range on battery power) would theoretically never have to buy gas at all. Some Volt owners have reported average mileage in excess of 1,000 mpg, and figures reported by a handful of Volt owners on fuelly.com run from a low of 77 mpg to as high as 168 mpg.

But wait! You can’t just make estimates based on the cost of gasoline burned – electricity costs money, too.

The EPA says the Volt can go 100 miles on 36 kWh, and for simplicity’s sake, lets assume a cost of 10 cents per kWh. So at 37 mpg (in gasoline mode) with gas at $3.85, the Volt costs about 10 cents per mile to drive on gasoline, versus 3.6 cents per mile on electricity.

Still with me?

Your mileage will vary

To get to that 26-year payback figure, we’d have to assume the Volt was driven 11,000 miles in gasoline mode, but only 4,000 miles in electric mode. Assuming the car exhausts its battery on each trip in order for gasoline mode to kick in, that would mean the car was only driven 114 times each year for an average of 131 miles of driving each day. That’s not very typical driving behavior, unless you’re a part-time pizza delivery driver.

So let’s assume the car is charged and driven every single day. Over a year, that works out to 41 miles per day, 35 in electric mode, 6 in gasoline mode. Again using the spreadsheet, that puts our payback at 11.8 years.

Or, we can assume the car is only driven on weekdays. That means 57.7 miles per day (35 in electric mode and 22.7 in gasoline mode). That would put the payback period closer to 15 years.

And, just for kicks, if you drove the car in electric mode 100% of the time, the payback would be around 10 years – more in line with the other cars in the Times’ comparison.

Now, that’s still a long time, but it’s also based on some other unlikely assumptions – such as, the price of gasoline remaining below $4 for the next decade (anyone willing to wager on that?).

A recent analysis by Edmunds pegged the Volt vs. Cruze payback period at 15 years with gas at $3 per gallon, and 9 years with gas at $5 per gallon, though those numbers seem to have been reached simply by comparing EPA mileage figures.

The bottom line is that the Volt is a different beast, whether it’s a smart financial decision will vary dramatically depending on an individual’s driving habits. In fairness, the Times does make this distinction deep in the text of the story, but no such nuance can be found in the accompanying graphic.

The 26-year payback period that the Times is reporting is based on a pretty unlikely scenario, and should be taken with a grain of salt.

How plug-in cars can face up to winter’s challenges

Posted on 01/18/2012 by Kevin Clemens

For gas-electric hybrids, cold weather can have a major impact on fuel economy. (Photo by Chad Kainz via Creative Commons)

January 18, 2012

Story by Kevin Clemens
Video by Rick Fuentes

Decades ago, plug-in cars were common in Minnesota.

For cars poorly suited for the upper Midwest’s frigid winters, a block heater plugged in overnight could keep the engine warm enough to start the next morning. Cars and trucks with electrical cords protruding from their grills were a frequent sight.

New technologies such as fuel injection, direct ignition, superior motor oils and better batteries have largely relegated that custom to history in all but the most frigid regions of the world. But with more than a dozen electric and plug-in car models due on the U.S. market in 2012, some Minnesotans will find themselves reviving the practice.

Shayna Berkowitz has some pretty strong opinions about how electric vehicles perform in Minnesota winters.

“Winter is very hard on this technology,” she said. “Batteries in winter do not equal success.”

Berkowitz knows something about the subject. Her company, ReGo Electric in Minneapolis, specializes in plug-in conversions for hybrid cars, adding additional battery packs to improve fuel economy while improving their all-electric range capabilities.

“To have an all-electric vehicle here in this climate is pretty radical,” Berkowitz says. “It’s a pretty dramatic thing to be able to do.”

However, there are some solutions that can make electric vehicles practical in cold climates.

Why cold weather is hard on batteries

There are several reasons why electric vehicles have special needs when it comes to operating in cold climates.

Batteries produce electricity through chemical reactions and these reactions slow as the temperature falls. A lead acid battery, like that used to start a normal gasoline engine, can lose almost 40 percent of its capacity as the temperature drops below zero.

The National Renewable Energy Laboratory (NREL) in 2006 found nickel metal hydride and lithium ion batteries used in electric cars could see a drop of more than 80 percent in capacity (PDF) at temperatures around zero degrees Fahrenheit, compared to 73 degrees.

Conventional cars with block heaters plugged into an outlet in Finland. The practice of plugging in gasoline-powered cars is still common in frigid climates, like Scandinavia and interior Alaska. (Photo by Suvi Korhonen via Creative Commons)

Cold batteries also do not accept charging energy as easily as they do when warm, so the benefits of regenerative braking, which uses the car’s drive motor as a generator when slowing down, is much less effective. In addition, an all-electric vehicle must use some of its battery energy to power items like the cabin heater, seat heaters and the defroster.

Consumer Reports has noted the Nissan Leaf’s 100-mile range on a charge during the summer months dropped to around 65 miles in cold weather, and Berkowitz says that a Toyota Prius that normally gets 45-55 mpg will only get 35-45 mpg in winter because of diminished battery capacity.

Preparing plug-in cars for winter

ReGo developed ways of dealing with cold weather in its hybrid conversions right from its beginnings four years ago. ReGo’s system includes electric resistance heaters and insulation around its battery pack. The heaters are powered through the charging cable that plugs into the electrical socket in the owner’s garage.

“Without the winterizing that we do, [the batteries] wouldn’t function,” note ReGo’s Berkowitz.

The same strategy is used by major automakers, as well.

As with ReGo’s conversions, the Nissan Leaf uses an electric resistance heater to warm the battery when the car is attached to the home charging circuit. In addition, the Leaf can draw power from its lithium ion battery pack to heat itself, as long as the charge level in the pack is above 30 percent. The heater comes on automatically when the temperature falls below -4°F and shuts off again when the battery temperature rises above 14°F.

The Leaf, as well as the Chevrolet Volt, can pre-heat their cabins and batteries when plugged in overnight. ReGo offers a similar system, not just for hybrids but also for ordinary non-electric vehicles to help cut down on cold-weather idling while the interior comes to temperature.

And while the cold poses day-to-day driving challenges for EV owners in the Midwest, another NREL study showed that a battery pack operating in a cooler climate like that of Minneapolis will last significantly longer (PDF) than one that spends its life in a hotter city like Phoenix.

Car companies who are building electric vehicles do extensive winter testing to fully understand the cars’ limitations and adapt for them accordingly. GM, for instance, tested several pre-production Chevy Volts in Kapuskasing, Ontario, where temperatures can drop to -40 degrees Fahrenheit. But only when a significant number of plug-in hybrids and electric vehicles hit Midwest highways will the success of these adaptations be known.

Meanwhile, ReGo’s Shayna Berkowitz understands the need to make her company’s electric conversions as trouble-free as possible.

“When it comes to transportation, people want reliable, dependable, consistent, easy technology,” she said. “Change is hard for people. They don’t want their commute to be a science fair project.”

Kevin Clemens is a freelance journalist and author who trained as an engineer and environmental educator and has been an editor and contributor at some of the transportation industry’s most influential magazines. He lives in Lake Elmo, Minnesota.

Rick Fuentes is a cycling writer and two-wheeled photographer.

This work by Midwest Energy News is licensed under a Creative Commons Attribution-NoDerivs 3.0 United States License.

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Volt owners respond