According to a Michigan Transportation Research Institute (UMTRI) study, indirect greenhouse-gas emissions by all-electric cars (considering electricity generation) widely varies depending on the country it is put into service.

Tesla Model X charging

In general, battery-electric vehicles are cleaner in terms of GHG emissions in 122 out of 141 countries, for which data were available. In 19 countries, coal-based power plants worsen the emissions.

Here is few results for BEVs:

Albania (which generates 100% of its electricity from hydroelectric power) would have an average 5,100.0 MPG ghg (0.05 L/100 km)

(which generates 100% of its electricity from hydroelectric power) would have an average Botswana and Gibraltar (which generate 100% of their electricity from coal and oil), each with 29.0 MPG ghg (8.1 L/100 km)

and (which generate 100% of their electricity from coal and oil), each with US is 55.4 MPG ghg (4.2 L/100 km) — close to the 54.5 mpge target for the US EPA’s current GHG regulations for 2025

is — close to the 54.5 mpge target for the US EPA’s current GHG regulations for 2025 China is at 40.0 MPG ghg (5.9 L/100 km)

is at average for the world is 51.5 MPG ghg (4.6 L/100 km)

"For each individual country, the calculations derived an equivalent fuel-economy value at which both BEVs and gasoline-powered vehicles produce the same amount of greenhouse-gas emissions. In other words, the calculations derived, for each country, a fuel-economy value that a gasoline-powered vehicle would have to exceed to produce lower emissions than a typical BEV, and vice versa."

Data for the study comes from the Union of Concerned Scientists (BEV miles-per-gallon-equivalent values based on well-to-wheels emissions of various electricity fuel sources) and the International Energy Agency (country-specific electricity production by fuel source).

source: Michigan Transportation Research Institute (UMTRI) via Green Car Congress, Quartz