I'd say a better title for this article/graph would be "How would electric cars affect CO2 output in European countries?" or something along that line.
There's far more to a specific car being a good idea considering the differences between EVs and ICEVs (but of course the needs vary inside countries as well). However, an electric car is much less attractive in a land of long distances where you often need to keep the batteries pre-heated to provide even reasonable range (and even keep your warranty!) – even if the country's electricity production is not dominated by fossil fuels.
EVs being popular have little to do if they are the best cars there – the gov subsidizes the hell out of them (compared to other cars that are highly taxed to pay for the welfare state) so much so, that a Model S retails there for about the same as a $25,000 Audi (US price).
(And why is Norway so rich to begin with, you don't need to wonder.)
There's far more to a specific car being a good idea considering the differences between EVs and ICEVs (but of course the needs vary inside countries as well). However, an electric car is much less attractive in a land of long distances where you often need to keep the batteries pre-heated to provide even reasonable range (and even keep your warranty!) – even if the country's electricity production is not dominated by fossil fuels.