Blogger Lindsay Leveen at Green Explored explains, in layman's terms, how the U.S. Environmental Protection Agency has created data "that disobey the laws of thermodynamics so that the worthless government policy of favoring plug in vehicles over gas or diesel powered vehicles can be supported by the public." The key, according to Leveen, is that the EPA deliberately ignores energy losses at each stage of the electrical process--meaning that the EPA's claim of 118 miles per gallon (MPG) for the Honda Fit means less than 41 MPG in reality.
Leveen walks through the calculations:
...the generation of electricity, the transmission and distribution of electricity, the conversion of the AC electricity into DC electricity, and the charging and discharging of the vehicle batteries all have energy losses associated with these activities. The average efficiency of power generation is perhaps 42.5%, the transmission and distribution efficiency is perhaps 90%, the AC to DC conversion and the battery charge discharge efficiency is about 90%. Multiplying all these efficiencies one can calculate that the overall efficiency is 34.4% to get electric power from fuels at the power station into stored electrons within the plug in vehicle’s batteries.
On this basis the 118 MPG equivalent is 40.6 MPG actual for the Honda Fit which is not much of an improvement to the gasoline version of this vehicle that has an EPA rating of 35 MPG combined for city and highway driving.
Remember, this is the administration that was going to take politics and faith out of science!