Miles Per Gallon Not Always Accurate for Electric Vehicles

As Electric Vehicles begin to reach the marketplace, consumers will most likely find it difficult to determine just how much money their electric car will save. The present MPG or Miles Per Gallon measurement has no standards for vehicles that use some or no gasoline at all. Some manufacturers are only measuring in-town mileage, which greatly favors electric cars, while others are making big assumptions and giving mileage numbers to vehicles that don't use gas at all. With so much inconsistently between manufacturers, consumers will have a hard time figuring out the dollar cost and environmental impact of their Electric Vehicle (EV) purchasing decisions.

Below: Respectively manufacturers state that the leaf will get 367 mpg, the Chevrolet Volt will get 230 mpg (city), which might be compared to the Toyota Prius hybrid at 51 mpg or the honda accord at 21 mg. Unfortunately, the numbers for the Nissan Leaf and Chevrolet Volt are very misleading. Actual MPG savings are most likely not more than 7.5MPG vs a Hybrid, like the Toyota Prius.

The Chevrolet Volt Gets 230 MPG... or Does it?

The Environmental Protection Agency has yet to standardize the way fuel consumption is measured for electric vehicles. For example, the Chevrolet Volt boasts 230mpg (this is only a city number, it does not completely incorporate highway usage). The number however, may be quite inaccurate -- even though it is based on preliminary draft legislation from the EPA (unfortunately the preliminary version of the legislation is not available to the public). The 230mpg number which GM built was based on a lot of assumptions, many of which are based on research of government driving pattern related surveys.

The Volt electric vehicle (EV) has two power sources, the electric batteries have a range of 40 miles, after this, only gasoline is consumed. If the vehicle is only used for short trips, gasoline will not be used at all. While if the vehicles is used for ranges beyond 40 miles, the electric part of the equation becomes smaller with increased distances.

Drivers routinely driving well beyond the 40 mile range will get mileage numbers substantially lower than the advertised 230mpg. Keep in mind with short distances, no gasoline is used at all. In other words, for short distances the MPG number is attempting to equivocate kilowatt hours to gasoline using. Attempting to use a MPG measure to evaluate electricity usage combined with gasoline usage is clearly flawed--the MPG standard was really designed for internal combustion engines. Comparing electric consumption to gasoline consumption is really like mixing apples and oranges. The problem is, depending on usage, the same exact vehicle can get drastically different MPG results. The EPA will have a great challenge creating a standardized and accurate way to measure this.

The Nissan Leaf: 367 MPG... Yet it Uses No Gas?

In contrast to the Chevrolet Volt, which is a somewhat hybrid vehicle, the Nissan Leaf is completely electric with no gasoline usage at all. The MPG Nissan rates the Leaf at 367 miles per gallon for combined highway and city usage. This Leaf's MPG is based on the assumption that one gallon of gas is equivalent to 82 kilowatt hours of electricity. Unfortunately, the actual cost of electricity varies too much to make this number accurate for most people, due to the fact that electricity costs vary greatly by region. The matter is made even more complex because manufacturers are applying different assumptions into electricity costs, resulting in MPG estimates which are really comparable. For example, with the Volt, electricity usage is not considered in the MPG while with the leaf, no actual gasoline usage is used to calculate the MPG number. So in fact, the volt has a hidden cost (electricity usage) which is not considered at all in the stated MPG. In fact, over a 500 mile distance the actual savings with an EV with a stated 200-300mpg vs a 50mpg hybrid vehicle (which a much lower stated MPG) might only be about 7.5mpg in total costs saved.

Conclusion

Right now, most experts agree that gasoline and electricity numbers will need to be reported separately. Mixing the numbers is confusing and in fact, even misleading. For example, telling consumers the Nissan Leaf gets 367 MPG, while it actually uses no gas, is without a doubt confusing for most consumers--especially since electricity costs are so inconsistent across the USA. Unfortunately, the EPA has not yet finalized standards and until then, consumers should almost expect continued confusion and lack of consistently of standards in MPG measures for EVs among the various worldwide manufacturers.

Tags: Electric Car, Electric Vehicle, Electric Vehicles, Lithium-Ion Batteries, Zero Emissions, Environmentally Friendly, Future of Cars, EV, Hybrid, Chevy Volt Electric Vehicle, Toyota Prius, Dodge Circuit EV, Nissan Leaf EV, BMW Mini E, E-mini, GM Buick Plug-In SUV, EPA MPG