After General Motors said today its plug in electric car, the Chevy Volt, would have a range of 230 miles per gallon in city driving, interest grew about whether its price tag of around $40,000 will truly bring savings to consumers savings on a daily basis.

According to General Motors, the Volt can drive for 40 miles on a single full charge of its lithium-ion battery pack with a capacity of 16 kilowatt hours.

The U.S. average retail price of electricity for 2007 is 10.65 cents per Kilowatt Hour, meaning it would cost about $1.70 to recharge the Volt fully. However prices vary in each state. In 2009 household electricity rates ranged from 17.45 cents per kwh in New York to 7.28 cents per Kwh in Idaho and up to 22.19 cents per kwh in Hawaii.

GM says the car would actually cost 80 cents to deliver up to 40 miles of electric driving because it would only take 8 kwh to give users 40 miles in the Volt. After the battery drains enough power to meet the 40-mile mark, the Volt's small combustion engine would kick in to produce electricity for the motor, according to the blog.

In comparison, GM estimates that the cost per mile to operate the Chevy Volt is approximately two cents per mile electrically versus 12 cents per mile using gasoline priced at $3.60 per gallon, the company said in a statement.

Users could also add savings by charging the auto during off-peak hours to take advantage of lower prices.

The Volt has a variable voltage charger that can accept either 110 V or 220 V, standard household outlets. It is estimated to charge in less than 3 hours in a 240 V and about 8 hours in a 120 V outlet.