MCLEAN, VA - It would take upwards of $4.50 a gallon before motorists truly accept electric vehicles, according to a recent Harvard study.

The study, "Will Electric Cars Transform the U.S. Vehicle Market?" reveals that plug-in electric hybrids, which have a gas engine in addition to batteries, are an average of $5,377 more expensive than gasoline-powered cars. All-electric vehicles cost $4,819 more over the life of the car, writes USA Today.

Notes the study:

Significant penetration of electric vehicles can only occur if American consumers decide to forego purchasing gasoline-powered cars and opt to buy electric vehicles. For this to happen on a large-enough scale to make a difference in oil consumption or pollution emissions, electric cars must be competitive with conventional cars across a wide range of attributes, including total costs (purchase, operations, and maintenance) and range. For this scenario to occur, gasoline prices will have to increase to $4.50-$5.50 per gallon, and battery technology will have to improve significantly, providing increased range at decreased cost. Both scenarios are possible. Government assistance in the form of continued support for research and demonstration of new battery technologies and a willingness by Congress to place a cost on oil imports and conventional and unconventional air pollutants would accelerate this process.