Electric vehicles (EVs) are commonly referred to as “zero emission vehicles”, meaning they emit no criteria pollutants or greenhouse gas emissions during use. However, sourcing and distributing the electricity required to operate an EV generally results in significant emissions. Therefore, knowing how the electricity is created is important.

Electricity can be created from a number of resources, including coal, natural gas, petroleum, nuclear, hydro, solar, wind, biomass, and more. ACEEE’s greenercars.org currently scores EVs and PHEVs based on a sales-based weighted-average electricity generation mix. While this more accurately reflects where EVs and PHEVs currently charge, it is still one grid assumption for every vehicle. To account for users’ local conditions, ACEEE has developed a calculator that will help potential electric vehicle buyers and existing owners understand the true impact of EVs in their state. The calculator adjusts the national Green Score of an electric vehicle based on the difference between the national weighted-average grid mix and the grid mix in the chosen state. This grid mix is determined by the state the user chooses, which is also linked to local gasoline and electricity prices.

Note that the calculator thus far doesn’t account for when the chosen electric vehicle is charged during the day nor seasonal variations in the electrical grid. Nevertheless, we hope this is valuable tool for consumers. We welcome any feedback about how we can continue to improve this resource, so please feel free to contact us at the email address listed on our contact page with your ideas.