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Ken Fry, GaiaTransport

Ethanol, natural gas, propane, diesel, and biodiesel have been used for a long time. Consumers have not been asking for any sort of gasoline equivalent metric to be used to compare these fuels -- just ask any truck driver or Mercedes diesel driver. Without having to be told, you quickly learn about the various economies, and MPGe just adds a calculation that you otherwise avoid by using simple MPG.

Electric vehicles have been evaluated on miles-per-kilowatt hour (or metric equivalents) for many years, so no new metric is needed there either. (I was a math whiz kid, but the last thing I want to do is drive down the road converting something known, miles per kilowatt, into something unknown and unnecessary: how much would the electricity I am using equate to in terms of gallons of some fuel that I am not using.)

Creating yet another MPGe metric is problematic, because the well-to-wheels metric has been used for many years by policy makers and environmentalists. The well-to-wheels MPGe metric is written into CAFE law, so creating and promoting a new one (which inflates the apparent efficiency of electric vehicles) can only lead to confusion.

For plug-in hybrids, the straightforward and simple method is to quote a miles-per-kilowatt figure for electric operation and the well-accepted MPG figure for gasoline or diesel operation, while in charge sustaining mode. Then if you want to figure your cost on electricity, it is profoundly simple. It is also much simpler, then, to calculate your operating costs on gasoline -- which otherwise gets buried in MPGe figures. Having the two simple figures lets you make your own informed decisions about how much of each energy source, gasoline or coal, to use.

How to deal with hydrogen and other exotics is a non issue. There is not enough of a market presence or expected market presence to justify the added confusion of another MPGe standard.

This new MPGe figure seems to have utility only for electric vehicle marketing departments. The standard well-to-wheels metric, as written into law, works much better for policy decisions, in which it is undesirable to disguise the resource depletion and pollution caused by electricity generation. Even the existing MPGe (w-t-w) already makes electric vehicles look extremely attractive -- no hype and spin is required.

Ken Fry, GaiaTransport

To elaborate a little:

I have driven diesel trucks, electric vehicles and ethanol vehicles. For the liquid fueled vehicles, knowing MPG is useful, because it helps in trip planning, and helps to avoid running out of "gas". MPGe cannot accurately serve that useful function.

In electric vehicles, I need to know how far I can go on a charge. I have no use for knowing how far I might go on a fuel I am not using.

If I am buying an electric vehicle rather than driving one, then I want a direct measure of energy usage in the units that I buy: kilowatt-hours. In a showroom, given a figure of 150 MPGe, how could I possibly quickly convert that into what matters to me: how many miles I can go on a kilowatt-hour, and how much that will cost. A gallon equivalent of gasoline has no useful meaning when I am buying electricity -- which obviously does not come in gallons. Depending upon the price of gasoline, an MPGe figure could make an electric vehicle seem more costly to operate than it really is.

I've talked with numerous electric vehicle owners. Not one has expressed any interest in converting kilowatt-hours into gallon equivalents of any particular fuel. Plug-in hybrid folks often think only in terms of the gasoline that they use (and have avoided using). They come up with all sorts of very large numbers: 800 miles per gallon used last week. (In my own plug-in hybrid, I used about 2 ounces last week.)

Another version of MPGe (beyond the one written into law) seems unnecessary, potentially confusing, and potentially misleading in critical ways, because it does not account for the inefficiencies and resource depletion associated with electrical power generation. That last is the problem most potentially damaging for our country's well-being.

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