It's a dramatic phoatie, however Skizo is right, that's actually mostly steam coming from the cooling towers.
The thing in the middle is the chimbley, the larger structures are the cooling towers.
In addition most of the stuff coming from the chimbley is probably steam as well. The exhaust fumes are "cleaned" before being released. That's not to say that they don't contain CO2 just that they are very difficult to see.