I checked the link and all I saw was the CO2 calculator. I tried working with the calculator and got no where. The article was rather brief and it did not say anything about the CO2 generated from a coal fired electric power plant necessary for the electricity needed to recharge a battery for one complete charge cycle. If you saw that information, could you please provide it?
You must have not clicked on the link by the OP.
Here it is:
https://www.motoringresearch.com/car-news/electric-cars-carbon-footprint-volkswagen/