230mpg

Photo: Source

This week General Motors announced that its new electric vehicle, the Chevy Volt, will get 230 miles per gallon.  Some critics and Nissan point out that the mpg claimed by GM is misleading.  Using GM’s formula the Nissan Leaf will get 367 miles per gallon.

To get to the bottom of this puzzle, we must first take a brief look at the newest electric vehicles available by both of these companies.  The Chevy Volt (priced at $40k) is slated for a limited release in 2010 and will be an automotive run on a combination of an electric battery and a gas-powered engine.  The Volt’s gas engine will kick in after 40 miles of driving on the battery. The Nissan Leaf (priced at $25K) will be all electric and Nissan claims the Leaf will get 100 miles per battery charge.  In theory, both models will be able to recharge their batteries from a standard electrical socket overnight.  For more info here are links to video on The Volt and The Leaf.

To better understand how GM calculated the Volt’s 230mpg, GreenCarReports.com did an investigation because standard EPA testing doesn’t apply to electric vehicles like the Chevy Volt.  If the test is under the distance of the battery range, it will never burn any gasoline and the mpg would be infinite.  Green Car Reports sited a similar test routine by Mike Duoba at Argonne National Laboratories.  In his test he repeatedly drives the Volt four EPA highway test cycles (10 miles each) until the battery is discharged and then drives one city cycle (11 miles)-totaling 51 miles.  Douba states that if the gas engine runs for 11 miles at 50mpg, the engine will use .22 gallons of gasoline. That amount is used over the total travel distance of 51 miles.  So, combining the amount of gasoline used after the initial distance the car can travel on battery works out to 232mpg for the vehicle.

In conclusion, 40 or 100 miles may not be as exciting as 230 or 367 respectively, but the miles that can be run on battery alone, the battery range, are the most important figures.  Why is that?  GM correctly points out that 70 percent of all U.S. vehicles travel less than 40 miles a day.