Time to start over on EPA mileage stickers?
Even more confusing with plug-in vehiclesThe Mini E electric vehicle will be rated at 99 mpg according to the EPA's preliminary methodology, while the Chevy Volt will be rated at 230 mpg.
Yet, the Mini E will cost less per month to operate according to Edmunds.
Thus, Edmunds believes that operating costs, for instance, might be a better way to provide useful information to consumers. Likewise, environmental concerns, such as yearly CO2 emissions, could be added as well.
Regardless, is it time to overhaul the EPA's mileage stickers?
Labels: fuel economy
posted by Dahcredyns at
8:52 AM
8 Comments:
Is it a price or an emission based methodology? If it were emission based, it would not get more than 60+ mpg.
Maybe adding miles/KWH will help.
The other key information on the EPA sticker is the "estimated annual usage cost". This number is based on the cost of driving 15,000 miles in one year. That number will stand out on an EV or hybrid as it is much lower....I guess we need to educate the public about that number...
Smurf,
According to BMW claims (which are likely to be an exaggeration) it is 4.4 miles per kw/h. In our previous discussion, we agreed that given an average amount of emissions of US plants (hydro, coal, etc... all combined), transition losses, electrical engine efficiency, etc. this gonna be an equivalent of 50-55 mpg.
Given a price of electricity of 15c per Kwh and the price of gas of 3$ per gallon, one gallon buys you 90 miles of electric driving. Therefore, it is probably a cost-driven mpg analysis.
Now, about the Chevy Volt: there is not honest way they can rate it at 230 mpg! Because in pure electric mode it is < 100 mpg (price-wise). If it is not purely electric, it is less than 60mpg!!!
LB,
You can figure out an all electric vehicle's miles per KWH simply by dividing the range of the vehicle by the total number of KWH's in the battery.
For example. A Telsa roadster is rated at about 250 miles per charge and it has a 53KWH battery pack. That adds up to about 4.7 miles per KWH.
With that in mind, 4.4 miles per KWH for the Mini E does not sound unreasonable...
It is not unreasonable, it is just idealistic. Yet, even with 4.4 miles per Kw/h, the emissions are about the same as for Prius. That is may be +-10-20%.
The emissions question is answered most simply by CO2/mile.
In electric mode that would be the emissions from the production of the electricity. You can use either the national grid avg production mix, regional data, overnight productino mix, what have you.
With the generator on, the CO2/mile would be from the generator. In that case, the CO2/mile is proportional to the gallons/mile.
BTW, gallons/mile, or gallons per 100 miles in many ways is a more useful number. It makes it easy to see the greater benefits of moving from the equivalent of 20 MPG to 25 MPG versus 50 MPG to 55 MPG.
20 mpg = 5 gallons per 100 miles
25 mpg = 4 gallons per 100 miles
50 mpg = 2 gallons per 100 miles
55 mpg = 1.8 gallons per 100 miles
thus far the EPA has largely made a mockery of fuel economy estimates, and it will only get worse adding various plug-in vehicles.
however, if the point is to help the consumer, the consumer only cares about one thing: costs. of course, since its the EPA, they should also include some kind of CO2 or pollution score.
still the EPA needs to proceed wisely.
while GM, for instance, might like the marketing possibilities of claiming the Volt achieves 230 mpg, reality might tell a very different story.
when autos aren't as efficient as claimed by the EPA, consumers don't blame the EPA, they blame the automaker. at least that's been my experience, and i've had many interactions with hybrid consumers along these lines.
thus i wonder if it wouldn't be better to provide a unique rating system only for plug-ins until more data is gathered.
ultimately, i don't think early adopters would have a problem with such a rating system.
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