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MILES PER GALLON EQUIVALENT AND ENERGY COSTS hat is MPGe? Miles per gallon gasoline equivalent (MPGe or MPGge) is an attempt to put alternative energy sources in perspective with gasoline. It is a way to compare the energy consumption of alt fuel (CNG, LPG) vehicles, plug-in battery electric vehicles and plug-in hybrid electric vehicles, plus hydrogen vehicles with the fuel economy of gasoline and diesel powered vehicles. One gallon of gasoline is equivalent to 33.7 kilowatt hours (kWh) of electricity. However, most people cannot relate to W This particular 2013 Volt came from the GM press feet and had a total of 2,700 miles on the odometer. The Volt keeps track of ���Lifetime��� fuel economy. That lifetime average was 58 mpg as driven under the widest possible variety of conditions and scenarios. So, what kind of gas mileage do you get from the Volt? A reasonable number is 58 mpg. Electricity is Not Free, Not Green The Volt is a study in contradictions for at least two aspects of electricity. First, p If the Volt is locked during recharging, an alarm will sound if the charge cord is removed. Remember that so you don���t accidently remove the cord before unlocking the Volt. (Photo courtesy General Motors) p Play to the Volt���s strengths. Use it in heavily urbanized areas and where the tour of duty is less than 35 miles and expect to never use gasoline. In more mixed driving, 58 mpg is easily attainable. (Photo courtesy General Motors) kilowatt hours per mile as a measure of ���fuel economy��� in their vehicles. So the EPA and NHTSA jointly developed miles per gallon equivalent (MPGe) as a common fuel economy unit of measure. With the Volt, it is impossible to cite fuel economy estimates that have any real world meaning. The EPA eventually adopted a dual economy estimate and had to use a miles per gallon ���equivalent��� (MPGe) rating. It is all very complicated, conditional and confusing. Their 98 MPGe (combined city/highway electricity) and 37 MPG (combined city/highway, gasoline-only) are totally meaningless. During our two weeks with the Volt, we averaged 24 mpg, 34 mpg, 39 mpg, 44 mpg, 58 mpg, 98 mpg, 109 mpg and 250 mpg depending on a bunch of different factors. Every single mileage number is true and real. Every number is a fully documented experience. To be more helpful, we put 1,600 miles on the Volt and had a grand average of 43 mpg. electricity is not free. It does a lot for the money, but it is certainly not free. Driven strictly by the battery, with no electricity from the gas engine, the Volt costs about $0.02 per mile ($0.10 per kWh). Compare this to a comparable, conventional gasoline-powered vehicle that costs about $0.12 per mile ($3.60 per gallon). Charging the Volt���s battery once per day from empty to full costs about $1.50, the cost of a bottle of water. So, while in electric operation, the Volt costs one-sixth what a gas-powered compact would cost. However, every time the Volt���s gas engine starts up, the cost of operation goes up sharply. Remember, the Volt can get as little as 24 mpg (Mountain mode, depleted battery). Second, electricity is not green. In the fne print, even the EPA is careful to point out their greenhouse gas and smog ratings are tailpipe only. Their disclaimer on the window sticker reads ���producing and distributing fuel and electricity also create p The lithium-ion battery pack is designed to last 10 years and 150,000 miles. The battery can be depleted 5,000 times without losing more than 10 percent of it capacity. (Photo courtesy General Motors) emissions.��� In the U.S., 45 percent of electricity is produced by burning coal. That is certainly not considered green. Another 20 percent of the electricity is produced by nuclear. Nuclear power is also arguably not green. Both nuclear and coal are excellent, low-cost methods of producing electricity. However, be intellectually honest about the Volt. Justify the use of the Volt on full-disclosure economic and environments facts, and not on na��ve, tree-hugging emotion. www.pfmmag.com 21