The California-based Union of Concerned Scientists analysed CO2 emissions for charging an electric vehicle and compared it to those of an average hybrid or conventional petrol-powered alternative. Their report divided the United States into ‘Good’, ‘Better’ and ‘Best’ regions, depending on the carbon intensity of the electricity.

This showed 45% of Americans live in the ‘Best’ regions, where using an electric vehicle will offer lower CO2 emissions than a 50mpg (60.5mpg-imp), a 46% reduction compared to an average conventionally-powered car at 27mpg. Strong hybrid markets, such as New York and California, performed even better, with CO2 output equivalent to an 80mpg (96.0mpg-imp) vehicle, while Alaska was the most energy-efficient place to use an EV at equivalent to 112mpg (134.5mpg-imp).

Of the remainder, 37% live in ‘Better’ regions where EVs can offer equivalent to between 41 and 50mpg (49.2-60.05mpg-imp), while the final 18% in ‘Good’ areas would see an average of between 31 and 40mpg (37.2-48.0mpg-imp). Even drivers in the highest-emitting region, the Rocky Mountains, would match the CO2 output of a 33mpg (39.6mpg-imp) car.

The report also pointed out that while coal accounts for 45% of energy generation at the moment, 29 states and the District of Columbia are in the process of retiring coal powered plants for renewable alternatives. Drivers can also expect to save between $750 and $1,200 (£472-756) compared to an average American petrol car, according to its findings.

Don Anair, the report’s author and senior engineer for UCS’s Clean Vehicles Program, commented: ‘This report shows drivers should feel confident that owning an electric vehicle is a good choice for reducing global warming pollution, cutting fuel costs, and slashing oil consumption. The good news is that as the nation’s electric grids get cleaner, consumers who buy an EV today can expect to see their car’s emissions go down over the lifetime of the vehicle.’