The US Department of Energy recently launched their eGallon website allowing the public to easily compare the costs of fueling a vehicle with electricity compared to a vehicle which uses gasoline.
The site explains why the tool is useful:
“The cost of driving an EV depends on the cost of electricity, which is measured in kilowatt hours. Yet, when consumers think of the cost of driving, it is usually determined by the price of a gallon of fuel. The eGallon provides a metric that is easily comparable to the traditional gallon of unleaded fuel — the dominant fuel choice for vehicles in the U.S.”
The graph below (from the eGallon site) shows the volatility of gasoline prices against the relative stability of electricity prices over the past 12 years.
This DoE news release explains how this has been an important factor in the rapid growth of plug-in electric vehicle sales – which have tripled from 2011 to 2012.