The number of electric vehicles on the world’s roads is surging, hitting a record number last year.  

That would seem to be good news, as the world tries to wean itself off fossil fuels that are wrecking the global climate. But as electric cars become more popular, some question just how environmentally friendly they are.  

The batteries in electric vehicles, for example, charge on power that is coming straight off the electric grid — which is itself often powered by fossil fuels. And there are questions about how energy-intensive it is to build an EV or an EV battery, versus building a comparable traditional vehicle.   Are electric vehicles greener? The short answer is yes — but their full green potential is still many years away.   Experts broadly agree that electric vehicles create a lower carbon footprint over the course of their lifetime than do cars and trucks that use traditional, internal combustion engines.  

Last year, researchers from the universities of Cambridge, Exeter and Nijmegen in The Netherlands found that in 95% of the world, driving an electric car is better for the environment than driving a gasoline-powered car.  

Electricity grids in most of the world are still powered by fossil fuels such as coal or oil, and EVs depend on that energy to get charged. Separately, EV battery production remains an energy-intensive process.  

Read more: Are electric cars ‘green’? The answer is yes, but it’s complicated