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Oliver Kuttner

While I agree with everything you say I would like to point out a further concern. If a Chevy volt is only used on short trips and if it is one of only few cars in the neighborhood which can be charged with night time electricity which is otherwise wasted then it may be in time a good application and a step forward. On the other hand if the car is used for many longer cycles and if it is sometimes charged during the day or in combination with many other electric cars thereby necessitating running additional power generation then it is a net looser. The main reason is that in the sum total a car with a $10,000.-- plus battery pack will almost certainly expire early at the latest when its first replacement battery fails. This early obsolescence combined with the extra energy needed and pollution created during the construction of the battery will never be offset by the gains in "efficiency". The root problem is that no matter how you describe it a 4000 lbs car is just not the most efficient way to provide transportation to several hundred pounds of human being. GM may enjoy to brag with their numbers but in the long run this is just another gimmick and lip service and if accounting is this abused I have no respect for what is otherwise a noble effort.
Electric cars make no sense until after we have replaced our coal power plants with clean sources of electricity. That may be long in the future or may never fully come.
Until then the only solution which has a net promise is efficiency. If GM put its effort into designing a 2000 lbs car like the Volt then the battery pack could be 1/2 the size and at $5000.-- the car might live one cycle longer...

Tim Lee

An indicator better than MPGe would be MPC (miles per cost of fuel). After all, this is the basic premise for knowing the MPG (or MPGe) of a vehicle. To consumers, it all boils down to costs. Another gauge would be to estimate Lifetime costs of the vehicle (purchase, fuel, maint, etc), and average those costs into the estimated total miles driven for that period, to come up with an average miles per dollar cost (or cost per mile) throughout the lifetime of the vehicle. Since buyers know how much they drive each year, it offers them better information for making purchase. The fact that a person can save $5000 in fuel over the vehicle lifetime has little justification if the lifetime cost of the vehicle is $10,000 greater.
Electric vehicles have little future potential for several reasons.
- Lithium mining is environmentally toxic and there are concerns about increased mining activity.
- Limited Lithium ore reserves. Estimates are that peak mining will only produce enough lithium for 1 million vehicles per year, but current vehicle production is over 70 million per year. Also, there are currently 1 billion vehicles in use worldwide, and growing.
- Current copper reserves are estimate to be exhausted in 65-85 years at current usage and growth. Adding the load for electric vehicles will exhaust those reserves much earlier, and drive costs far higher. If you think electric vehicles are expensive now, wait until they go into mass production and copper prices go through the ceiling. Increased production of electric and electric hybrid vehicles will drive prices up for lithium and copper as those resources further deplete, which means increased costs for all goods using those minerals. That is the downside. The upside is that carbon nano-technology may be able to replace copper, though that could still be 50 years away.
The next major technology should be one that is cost effective and sustainable. It seems that electric vehicles are neither, so it can only develop as a minor technology. Per 1 million BTU, electricity costs $44.00 (at $0.15/kWh), gasoline costs $28.00 (at $3.00/gal), and natural gas costs $12.30 (at $13.00/mcf). Strictly comparing on energy potential, electricity has a far greater cost. The only reason that an electric vehicle can claim a lower fuel cost is that they are much more efficient(95%) than the internal combustion engines(20-25%) of today, however, the whole process from '(grid)generator-to-transmision-to-battery charge-to-motor consumption' has an overall low efficiency of less than 45%.
The most likely technology for future motive concerns should be high efficiency combustion engines achieving efficiencies on the order of 80%+ and utilizing a hybrid system to recover, store, and deliver energy as needed. Such technologies would operate on renewable, clean biofuels, and can be built from abundant, sustainable materials. The eventual biofuel infrastructure could be much more economically beneficial then increasing the electrical infrastructure to accomodate EV's since more farmers in more regions would be involved (vs few large corps), and thus invoking more price competition as well.

Tim Lee

The GM Volt's claim of 230 MPG is a perfect example of a shell game. They know that people (in general) relate MPG to driving costs, so by specifying only the gas fuel used in their driving test and tying that number to the total miles driven, disregarding the fact that most of the test miles driven were on the pre-charged battery, they can confuse potential buyers into thinking that this vehicle will have extremely low driving costs. Those who get suckered into this will have a big surprise when they see their monthly electric bill. The Volt has a 8kWh battery which can drive 40 miles. In San Diego at $0.15 per kWh, that would cost $1.50 to charge assuming an efficiency rate of 80% for charging. So, if you drive 40 miles per day, it will cost you $1.50 per day ($0.0375 per mile) for electricity and your MPG will be infinite cause you will never have to use gasoline. If you drive 39 miles on electric and 1 mile on gasoline, your electric cost will be $1.46 and your gasoline cost will be $0.10 (assuming the Volt engine gets 30MPG and gasoline cost is $3.00/gal), which makes your daily driving cost $1.56 and using GM's method, calculates to over 1200MPG. Driving 35 miles on battery and 5 miles on gas yields a 240MPG rating. Driving 40 miles on battery and 6 miles on gas yields 230MPG. The more miles you drive on the gasoline engine vs the precharged battery, the more the MPG factor reduces. With that in mind, driving only on the gas engine would cost $4.00 per day for those same 40 miles, so electric could save $2.50 per day under the previously mentioned factors, which could be $625 per year (250 days per year) and $4400 over 7 years (avg ownership).
This ridiculously exaggerated claim of 230 MPG from GM (and those from Nissan and others) shows exactly why a measurement basis should be tied to average energy costs per mile, or average miles per dollar of energy.

Matt Prater

Don't hate the players, hate the game.

To the Volt has been attached a perfectly legal mileage value. Additionally, the Volt's packing top-notch technology.

Most of the people complaining about this rating are just mad they didn't get there first.

Additionally, if the regulation was different, I respectfully propose that GM would have scooped them using that regulation too.

Much as you want to hate GM (not sure why there's this unending anti-GM bias), they're not idiots.


Nothing in the preceding commentary about the reduction of human-caused degradation of the atmosphere, which would seem to decry the purpose of the X-prize.

And, while it is vital that we eliminate coal-fired electric power plants, as a general statement, the above comment is incorrect that electric drive is disadvantageous when the electricity is coal generated.


According to GM, the volt gets 40 miles before it uses up 50% of its 16kWh batteries. (source: http://gm-volt.com/2007/08/29/latest-chevy-volt-battery-pack-and-generator-details-and-clarifications/)

That would be 27,296 BTU for 40 miles.

By your own standards: 40/[27,296/116,090] = 170 MPGe, if operated purely on batteries.

Granted, that's not a 200 or 300 mile run, but with refueling stations popping up even at places of employment, some can go indefinitely on pure battery charge.

Patrick Walsh

@ Tim Lee:
MPGe is a basis on how much fuel, whatever its type, a vehicle uses. Your proposed MPC is based on the cost of fuel, which is highly variable. It is more useful for consumers to know how much fuel the vehicle consumes compared to other vehicles - they can do the math after that for fuel cost to them.

As to lifetime costs for the vehicle, that too is variable and dependant upon maintenance performed over the lifetime of the vehicle.


As I posted in another forum, if you take into account the inefficiencies of the electric grid, the Volts mpge should be a whopping 50 mpge. This should not be a surprise, if a car weighs the same as Prius, regenerates from braking similar to a Prius, and has similar tires and Cd as a Prius, the energy consumption to move a mile should be similar.

When are grid is all solar, wind and nuclear, then we can say the Volt is 170 mpge.

I applaud the attempt at a mpge, but it is still incomplete.

Ken Fry, GaiaTransport

The last thing the world needs is yet another, different MPGe. The well-to-wheels MPGe that has been in the law for many years is all we need for policy. For consumers, if you want to know how much E85 or diesel is costing you per mile, the competition MPGe is useless, because you buy fuels in real gallons, not equivalent gallons: when you fill up with diesel, you are not buying gasoline. Here are a few of the categories of people who would suffer from yet another flavor of MPGe:

1. Automotive engineers and enthusiasts: The existing well-to-wheels MPGe works fine. When Motor Trend found the Tesla Roadster got 55 MPGe, everyone understood. Likewise, when electric vehicle advocates came up with a 59 MPGe figure for the GM EV1, everyone understood. That was an impressive figure – about twice the mileage of a contemporary sports car. Back then, grossly inflating electric vehicle efficiency figures was not considered necessary, desirable, or honest. Applying the competition MPGe gives these vehicles figures so high that they seem silly.

2. An electric vehicle owner: You want to know how far you can go per kilowatt-hour, which is what you pay for. The existing miles-per-kilowatt-hour calculation could not be simpler. Calculating your cost per mile based on MPGe would be a horribly time-consuming and convoluted process. MPGe would make a good situation bad. At the same time, it obscures the environmental impact of electrical energy generation. That’s worse than bad. The already existing legal well-to-wheels MPGe does not make this error

3. Environmentalists: You don’t need yet another MPGe, because the well-to-wheel standard which has been used for decades in the law shows the real resource depletion potential of different energy sources (fuels) and energy carriers (such as electricity and hydrogen).

4. Truckers and diesel Jetta owners: It has no relevance, and makes what would have been a simple calculation difficult.

5. Sellers and developers of PHEVs: You get raked over the coals by this MPGe. In the competition, there could be a stunningly efficient PHEV that gets 100 mpg on gasoline (100MPGe) and goes 10 miles per kilowatt-hour (340 MPGe). The “special case” PHEV MPGe rating is 77.3 MPGe. One might well ask how a vehicle that gets 100 MPGe on gas and 340 MPGe on electricity can possibly be rated 77.3 MPGe. Magic.
Here’s a description of the calculation: (http://autoblog.xprize.org/axp/2009/08/calculating-mpge.html) You can try the “special case” PHEV calculation in the spreadsheet.

The Tesla roadster, a true electron guzzler, gets 3.3 miles per kilowatt hour, consuming 3 times the electricity of the PHEV we just rated at 77.3 MPGe. What is its rating? 109.8 MPGe! (See the chart in this post: http://autoxprize.typepad.com/axp/2008/01/computing-mpge.html)

Plug in the values for the Chevy Volt: 40 MPG and 250 watt-hours per mile: 30.9 MPGe, from a vehicle which uses less electricity than the 109.8 MPGe Tesla.
Can one avoid the thought that having a board position on the X Prize Foundation is paying off for Tesla’s Elon Musk, the outspoken critic of the Volt?

Jim Bullis, Miastrada Co.

Ken Fry seems to have an accurate technical compass. The PA Xprize folks have done it badly enough, but even Ken may have missed the latest round of absurdity put forward by GM on the plug-in Volt as well as Fisker (as well as the plug-in Hummer which is basically the same as the Fisker -- both show their true greenishness by the use of a 260 hp supercharged engine.). Maybe Tesla has jumped on this opportunity to bamboozle the public, but I can't keep up with it all.

The latest is the trick to completely ignore the electric energy in the MPG calculation, for after all, electricity does not come in gallons, so why should it be counted?

Argonne National!! Laboratories adds credence to this nonsense, though noting in passing that the mileage does depend dramatically on the charging frequency. See page 23 of:

Although they point out that you can get any number you like just by changing the ratio of time on the engine to time on battery, they fail to note that the result is complete gibberish, as any such system should be reasonably called.

Compared to this latest round of nonsense the PA Xprize nonsense sounds like enlightened wisdom. Although they are doing it wrong, at least they count the electric energy.

Acai Force Max

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Oliver Kuttner

While I agree with the basic energy analysis of Ken Frye I want to point out a few things in defense of the X Prize People's method (MPGe). I believe that they went to the Plug-to-wheel standard because they wanted to give "new" technology (electric cars) a break because they have several things on their side:
1- The technology effort is young and there may be some leaps in efficiency yet to be unearther in the long sequence of energy losses encounterd between making electricity and driving a car with it.
2- If using otherwise wasted night time electricity then there is a true gain.
3- There are certain applications in which moving the pollution out of an area may be an advantage.
4- As previously pointed out electric cars have this moving efficiency curve that does make them potential winners in some very narrow circumstances mostly linked to short drivecycles (and therefore light battery loads).
There may be other issues.
Thus because of this variable goal no matter what you do you never get it right for all circumstances.
The X Prize people are using in their competition the wells to wheels pollution standard. Few people realize it but it is that standard which will limit the amount of electricity used by the competitors. Thus even the electric car that "gets 150 mpg" may well not be able to use the "Gallon" implied here because with full use of the electricity equivalent gallon they fail the emissions requirement.
The truth is this is very complex and difficult. In the end I do agree that the standard in the end shoud be wells to wheels because we live on a planet that has a limited number of potential stored BTUs available and all those BTUs have environmental consequences - if used. Thus the only real step forward is to reduce the actual energy used (in BTUs at the well) counted from the source. It is too bad that so many people do not take the time to understand these circumstances (I mean professionals in industry and government) and just go and build another device (like Fisker) which gives in the end no real benefit but is just another "toy".
I do not mind the toy. I do mind the false green claim and the fact that so many people follow these claims and make decisions based on them. The X Prize is right in focusing the attention of many people in more detail and they will be a major contributor to true science when they will debunk some of the previously stated mileage claims. In this environment of smoke and mirrors someone introducing another set of numbers may well do much good if, for no other reason, than to make people to start to think. All the numbers just do not add up.
The other thing the X prize is doing is to debunk the idea that there are no other options. We tend to sleepwalk and we tend to believe our leader. In this process we may loose precious time believing those in charge have the matter in control with the (now dead) coming of the hydrogen economy (George Bush) or the coming Electric car (the present story). The truth is Presidents are really busy and we as citizens must use out heads. This is where the X Prize shines. It takes the focus from a few influential firms and gives a platform for many others. Thank you Our grandchildren's lives may well depend on this discussion.

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