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. To address this, the Department of Energy developed an eGallon tool that shows the fuel cost of operating a vehicle on regular gasoline versus electricity for any given distance.
The eGallon price is calculated using the most recently available state-by-state residential electricity prices. The state gasoline price is either the statewide average retail price or a multi-state regional average price reported by EIA. Home-based solar installations are not considered.
Using this tool and comparing the cost difference between gasoline operation and electric operation, all states showed cost savings for electric operation. Savings are for 19 May 2018.
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.