Edmunds.com: EPA's Fuel Economy Guide Should Be Based on Cost, Not Mileage
By Scott Doggett November 12, 2009
By John O'Dell and Scott Doggett
(Updated 11/13/09 to correct Chevy Aveo monthly fuel figure.)
"Miles per gallon" made sense when all cars drank gas, or diesel, and that was that.
But with the advent of rechargeable electric vehicles, whether all-electric or plug-in hybrid, the fuel-use scene gets quickly blurred.
How many miles per gallon do you assign to a Nissan Leaf, with a lithium-ion battery and no fuel tank or internal combustion engine?
Edmunds.com proposes the EPA scrap its mileage-based fuel-economy guide, right, for one built on fuel costs.
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Can't be done - unless the consumer's an electrical engineer with a minor in math.
To make it easier and more accurate for consumers to get honest comparative information, Edmunds.com is proposing to the EPA that it replace the mileage-based fuel-economy stickers it's been putting on new cars since 1975 with stickers that display monthly fuel costs.
That's right, replace MPG with MFC.
Then consumers could see that at 1,250 miles a month, a 2010 Toyota Prius would cost, on a national average, $67 a month at the pump, while an electric Mini E would cost $49 a month to "fill" from a 220-volt charger in the consumer's garage; the monthly gasoline bill for a four-cylinder Chevrolet Aveo would be $11 $111, and a 2011 Chevrolet Volt - running on gas and electricity - would cost $54.
That's information people can use to make informed decisions.
Edmunds.com - our parent - is submitting its recommendation and rationale in a letter being sent Friday morning to the agency and to the Department of Transportation.
We like the idea, and would even if Edmunds.com didn't send us our paychecks.
Changing decades of habit won't be easy - everyone says MPG and we all think we know what it means. But mentally changing kilowatts per mile to gallons per mile and figuring the cost of electricity versus gasoline is a lot to ask of people, and that's what people will have to do to make valid comparisons in the auto market of the not-so-distant future.
The time to make the change is now.
The EPA is proposing an awkward system that converts the energy in fuels other than gasoline and diesel - that would include electricity, ethanol, methane, biodiesel, natural gas, hydrogen and others we haven't even thought of yet - into what it calls miles-per-gallon-equivalents, or MPGe.
But that, says Edmunds.com CEO Jeremy Anwyl, is likely to cause more confusion and to perpetrate a lot of misinformation.
A new Toyota Prius, for example, earns an EPA rating of 50 MPG and General Motors is reporting that its new Chevy Volt cold be rated at 230 MPG-equivalent by combining its electric consumption and gasoline use over a regular EPA test cycle.
"From this we could reasonably assume the Prius is more than four times more costly to operate than the Volt," Anwyl told us. "But we would be wrong."
The EPA already provides "annual usage costs" data on window stickers, and makes the required assumptions necessary to do so. Edmunds is suggesting that consumers would benefit if window stickers on new vehicles highlighted these amounts instead of the traditional MPG numbers.
To help consumers make even better comparisons of gas and diesel cars and trucks to conventional and plug-in hybrids, battery-electric vehicles and, if that day ever comes, hydrogen fuel-cell electric vehiles, Edmunds also is urging the agency to require automakers to use EPA-provided monthly fuel cost estimates instead of MPG figures in their vehicle marketing campaigns.
Edmunds.com has compiled a list of monthly fuel costs for most 2009 and 2010 model-year vehicles so that shoppers can make realistic comparisons. To produce this list, Edmunds statisticians used data and assumptions that mirror those used in our True Cost to Own tool.
We're not suggesting that the EPA adopt "TCO" for its own calculations, but we do want the agency to make public the assumptions it is using now to determine the monthly fuel cost estimates for window stickers.
To illustrate its case, Edmunds.com supplied the following chart, which sets forth the projected monthly fuel costs for a variety of vehicles.
In reference to the chart, Anwyl noted that "we find that electric vehicles do enjoy a cost advantage over their counterparts powered with other technologies - but this advantage is nowhere near as great as the proposed EPA [ miles-per-gallon-equivalent] ratings would imply.
O'Dell is Senior Editor of Green Car Advisor.
Doggett is a regular contributor.
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"That's right, replace MPG with MFC."
Is the EPA going to use the same cost per unit of fuel year over year? I would assume not. The price of a gallon of gas, a gallon of diesel, a kilowatt hour, etc. will vary from one model year to the next.
As such, MFC on its own, is not enough. You still need something to measure vehicle efficiency. As fuel prices fluctuate, so will MFC.
For instance, if the price of gas drops and the price of electricity skyrockets, you might come to the conclusion that a full-sized ICE truck is more economical than an all-electric sedan. While the out of pocket expense for fuel might be less for the truck, is it really more efficient?
For a more apples-to-apples comparison, you might be shopping a used ICE vehicle vs a new ICE vehicle. If the price of gas is twice as much now as it was when the used vehicle came out, you can't make a fair comparison as to which vehicle is more economical (or more efficient) based solely on MFC. But you can with MPG.
I agree with John and Scott: MPG doesn't work for all vehicles. I'm ok with MFC. But if you can determine how many miles a vehicle can travel on a unit of fuel, I want to know.
$11 a month for an Aveo, but $67 a month for a Prius?
Yes, excellent. The Heating and Cooling industry has a similar issue with "Hybrid" heating systems that can be switched from natural gas or oil to electric driven heat pumps. We use a spreadsheet to insert the current price of fossil fuel and the kilowatt hour price of electricity to find which combination is cheaper.
The Volt may have a situation where just running it on gasoline rather than charging the batteries could be cheaper.
TYPO!!!! Should have been $111. Copy has been corrected. Thanks.
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