The CO2 emitted during electricity generation is very different according to fuel type, with production from fossil fuel clearly producting most. The calculations used on this website use the values for each fuel type as published by the IPCC in 2014 as presented here: CO2 emissions per fuel type.

NB. The small countries with large wind+solar fractions in generation, in particular Denmark,  have a large dependance on imports/exports for load balancing.