Chevy Volt plug-in electric carGet ready to do a lot of math if you're keen on buying a Chevy Volt and want to compare fuel costs between electric and gasoline cars. It'll be a sharp change from what auto shoppers have been doing for years: simply eyeballing the gas-mileage ratings displayed on new-car stickers in dealer showrooms.

As major automakers start to roll out plug-in electric hybrids (the Volt) or all-electric cars (Nissan's LEAF) later this year, consumers will see mileage numbers on the price stickers that will attempt to explain these cars' fuel economy. But what many shoppers could end up finding is confusion.

That's because the federal Environmental Protection Agency is still working on rules for determining fuel ratings and labels for these alternative-fuel vehicles. At the same time, the EPA also is working with the National Highway Traffic Safety Administration on labels for greenhouse-gas emissions for electric cars. The complication there: how to take into account emissions from power plants, not just the cars' tailpipes.

The EPA expects to propose the new rules this summer, after which it will take public comments and make revisions before adopting the final versions.

How Will Consumers Compare Cars?

But in the meantime, many automakers are preparing to launch cars that run either completely on an electric motor or on a combination of an electric motor and gasoline engine. Both GM and Nissan (NSANY) plan to start shipping the Volt and LEAF, respectively, later this year. Ford, Toyota and others intend to follow suit later.

The big question that all these carmakers are grappling with is how they should label the fuel economy of their models. Since these cars can run on electricity alone, should they be labeled in miles per kilowatt-hour or in kilowatt-hour per miles? If so, how can consumers compare the mileage ratings of electric cars with gasoline vehicles' familiar miles-per-gallon (MPG) ratings?

Further muddying the mileage picture: Consumers will need to know their electricity rates, which can fluctuate from day to night. To calculate per-mile operating costs, rather than monitoring gas-pump prices, they'll have to pay closer attention to their utility bills.

"Engineers say we need to give consumers lots of data, so instead of two numbers, you'll have maybe six or even 10 numbers," says Michael Love, national regulatory affairs and powertrain planning manager at Toyota (TM). "But that probably won't work -- people's eyes would glaze over. So the debate is: How do you give them valid information without overwhelming them?"

The Making of a Marketing Dilemma

The lack of adequate labeling rules has made it particularly difficult for GM to talk about the Volt's fuel economy, which is the first in a new category of cars. The Volt comes with a primary, battery-powered electric motor and a small backup gasoline engine. Charging the Volt's lithium-ion battery will require plugging a cord into a regular wall socket or especially designed equipment for speedier charging. GM announced pricing and financing options for the Volt earlier this week.

GM says the Volt's battery can last 40 miles, after which the gasoline engine kicks in to extend the driving range for another 300 miles. It hasn't divulged the size of Volt's gas tank, except to say it's less than 10 gallons.

GM came up with these driving-range numbers based on current EPA testing procedures. The rub is that the EPA has no rules for calculating the final fuel ratings of plug-in electric hybrids -- the numbers consumers would need to comparison-shop and figure out how much they might have to spend on fuel per trip or month.

GM once touted 230 MPG for its Volt by using a method under consideration by the EPA. That number raised eyebrows and then disappeared from the Volt marketing campaign when the EPA reportedly decided not to use that formula. Nissan also tossed out an eye-popping 367 MPG for its LEAF last year, using the same proposed method, but it has stopped promoting that figure as well.

Until Further Review

Right now, carmakers can use existing EPA rules to come up with fuel ratings for all-electric cars, ratings that can be expressed in kilowatt hours per 100 miles, Love says. But the EPA is looking at whether to adjust those numbers to better reflect mileage that consumers can achieve in every-day driving conditions. Since adopting MPG labeling in the 1970s, the EPA has had to twice modify how mileage is determined because consumers complained that they weren't close to getting the fuel economy listed on the labels, he says.

So for now, electric-car manufacturers are holding off while the EPA completes its review. Nissan currently trumpets only the LEAF's range of 100 miles per charge, which is the limit of its range because it's all-electric, with no gas-powered backup.

GM is working with the EPA to come up with an interim label for the Volt launch later this year, says Tony Posawatz, vehicle line director for the Volt. "It's probable that the label for the Chevy Volt will only last one year, until the standard is here," Posawatz says.

What Should the Label Say?

Given that MPG refers to how much distance you get per gallon of gasoline, an equivalent for electric range would be miles per kilowatt-hour. But some carmakers have looked at kilowatt hours per 100 miles, which better reflects electricity usage.

For example, BMW came up with a fuel economy of 33 kilowatt-hours per 100 miles for city driving for its Mini E (36 kilowatt hours per 100 miles on the highway) when it launched a field trial of its Mini E last year. But like other manufacturers, BMW also is waiting for the EPA to complete its work on mileage ratings for all types of electric vehicles before settling on a final version of its Mini E label.

For automakers, figuring out the labels is only part of the challenge of selling electric cars. They expect to face lots of questions from consumers about how to translate those numbers into fuel costs. For one thing, consumers will have to know, at least roughly, their electric rates, which few could recite off-hand currently. Plus, electricity tends to be more expensive during the day or early evening, when demand is high, and cheaper overnight.

Mileage -- or Carbon Footprint?

Aside from fuel economy, consumers also will have to learn about emission ratings, which reflect the federal government's desire to raise awareness of climate change and to curtail carbon emissions. And in that labeling, the EPA has to take into account emissions from the cars themselves and from electricity generation at power plants, Love says. And even that effort has added complexity because electricity from coal-fired power plants would have higher emissions than power from renewable sources such as solar or hydroelectric power.

And if the electric-car market really takes off, automakers expect a move away from MPG standards altogether. "In the future we'll see a trend toward carbon dioxide emission labeling," Posawatz says. "We've been trained on MPG for decades now, and it's not a measure of goodness."

In the meantime, consumers better be ready to bring their calculators and utility bills when they go out shopping for electric cars.

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Im not sure i understand this, can someone tell me how burning a fuel at a different place is better for the environment? If i burn coal to produce electric why is that better then burning gas? Also if i have 2000Lbs Of NiCad in the car, and i junk it, how is burning the batteries better then gas to begin with? Also with a sticker at 40K, if i bought a corolla, how long would 24K dollars towards gas last me?

September 10 2010 at 11:29 AM Report abuse rate up rate down Reply

it is all Obamas fault

September 09 2010 at 8:51 AM Report abuse rate up rate down Reply

In areas of the country where electricity is from nuclear plants, there are no emissions. So theoretically, the EPA gas mileage is infinite. Nope! The driver and passengers are emitting, producing, polluting by breathing and exhaling Carbon Dioxide! Horrors! Hold your breath!

August 08 2010 at 11:15 PM Report abuse rate up rate down Reply

Need to start looking at dollars per mile instead of miles per gallon and the metric and that will work for any type of car or fuel.

August 08 2010 at 2:43 PM Report abuse rate up rate down Reply

It might not be a bad idea to equip the charging recepticle with it's own meter/clock/recorder for a start. A digital unit like this made in the millions would be dirt cheap and could even use the same type externarly radio prompted system used by the so-called "atomic" clocks sold in Walmart and stores.

It would be a cheap reliable, serviceable system. Unfortunately, companies tend to discard cheap and reliable for expensive and spotty. Go figure.

August 08 2010 at 9:31 AM Report abuse rate up rate down Reply

You can toss all the benefits of electric vehicles in the trash. You will still need petroleum for the manufacture of the tires, plastics and battery shells. Consider the additional toxics from the batteries and disposal, the fuel to generate the power to recharge from your electric grid and the excessive vehicle cost. You think we're getting a smoke screen from the government. Yup. They are clueless or could it be that the investment with BP in building a hydrogen plant is truely the answer and they are just trying to keep us believing it's that complicated. Hydrogen will require the least amount of retrofit, less toxins and more affordability. But then gosh, how could they justify global warming? My bet is hydrogen. Certainly less dangerous than 20 gallons of gasoline in a steel tank. Much less weight so mabe better milage. Would be much easier to convert existing fueling stations as they become commonplace.

August 08 2010 at 9:05 AM Report abuse +1 rate up rate down Reply

One thing nobody remembers or want's to talk about. When a gas powered car runs out of fuel it stops. When an electric runs out it goes slower,and slower, and slower until it finally can't make it over a rise. In the meantime the driver turns off the heater, AC, head lights, anything to stretch it a bit longer. Years ago Comsumer Reports tested electric cars in the last "do gooder" phase of electric cards, and this is what they reported. Of course back in the early days there were electric, steam and gasoline. The first two were easy to drive, the gasoline were crude and difficult, but they won!

August 02 2010 at 5:35 PM Report abuse rate up rate down Reply

Umm...who really gives a rat's ass...

August 02 2010 at 5:03 PM Report abuse rate up rate down Reply

What is the costs of maintenance for a hybrid versus a gasoline vehicle? I assume that a hybrid will be more expensive to maintain.

Next what type of electrical provision will a homeowner have to add to their home to charge one or two, or even four cars for a "modern family? How many cars can be charged at the same time (over night). How much will the electrical work cost the homeowner? What about people who live in condos or apartment buildings? How will they charge their vehicles? Who will pay for the electrical outlets and pay for the electricity to charge cars in a parking garage? What about if one only has parking in a large parking lot???

There are lots of unanswered questions in all of this, isn't there? Will there be a "universal standard for charging connections or will that vary by manufacturer?

August 02 2010 at 3:46 PM Report abuse rate up rate down Reply

Well, if the Volt is going to cost $414K, which is approximately $20K MORE than a comparable gasoline powered vehicle ... and if $20K is the equivalent of approximately 8 to 10 years of gasoline for a stadard vehicle, then how does it make any sense inbuying a hybrid car? How much do the batteries costs after the 3 yr warranty? ... approximately $8K?

Hybrid vehicles are simply NOT costs effective at this point. When the savings in gasoline equate to the difference in the price between a hybrid versus a stand gasoline vehicle, then it might be costs effective; BUT NOT UNTIL THEN.

August 02 2010 at 3:39 PM Report abuse +1 rate up rate down Reply