Electric vehicles are more efficient than internal combustion vehicles, but fuel cost comparisons can be complicated because the price of gasoline and residential electricity vary considerably by state, according to the US DOE data.
Using this tool and comparing the cost difference between gasoline operation and electric operation, all states showed cost savings for electric operation.
The average fuel cost savings for all states was 60% and each of the states except for Hawaii had savings of greater than 20%. The state of Washington provided the greatest fuel cost savings (74%) for electric vehicle owners.
Residential electricity rates, which are high in Hawaii and low in Washington state, greatly influence the level of savings.