If you buy a new electric car today, it won't take long for it to have less environmental impact than a gasoline car, but it depends on where you plug in, according to new Reuters analysis.

Developed by the Argonne National Laboratory, the Greenhouse Gases, Regulated Emissions, and Energy Use in Technologies (GREET) analytical model used by Reuters tracks the lifetime carbon emissions of both internal-combustion cars and EVs. It includes not just the "tailpipe" emissions of a given vehicle, but also emissions related to materials sourcing and manufacturing, among other things.

Using this model, Reuters found that, in the United States, a new 54-kilowatt-hour Tesla Model 3 must be driven 13,500 miles before it becomes cleaner than a Toyota Corolla achieving an average 33 mpg over its lifetime. However, if the same Tesla were driven in Norway, it emissions "break-even point" would come at just 8,400 miles, according to the analysis.

GM and EVgo expand major-metro fast charging

GM and EVgo expand major-metro fast charging

The difference is power grid generation mix. In the U.S., 23% of electricity still comes from coal-fired power plants, but Norway generates almost all of its electricity from hydro sources.

Alternatively, in countries that get the majority of electricity from coal, such as China and Poland, the Model 3 would only become cleaner than the Corolla after 78,700 miles, according to the analysis.

EVs generally have higher emissions from materials sourcing and manufacturing than gasoline cars. The average electric car accounts for 8.1 million grams of carbon emissions before it reaches the first customer, compared to 5.5 million grams for the average gasoline car.

But once on the road, even when charged exclusively from a coal-fired grid, EVs contribute to 4.1 million grams per year, compared to 4.6 million grams for gasoline cars, according to the analysis.

Tesla charging on EVgo network

Tesla charging on EVgo network

It's another example of how EV emissions rates aren't static; they'll keep getting cleaner through their lifetime as the grid greens.

Still, lifetime EV carbon emissions have remained a hotly-debated topic. Some studies had been downplaying the advantage of EVs due to outdated data on the power-generation mix, but a study last year found that EVs are already cleaner than gasoline vehicles in 95% of the world.

The team at Carboncounter.com has also aimed to help navigate ideas like EV cost vs. carbon benefit, and also takes advantage of the GREET model used here.