Ash separators and flue gas desulphurisation. That keeps the stack from having grey/brown or yellow fumes, which would contain the ash as solids to drop out or the sulphur dioxide that contributes to acid rain. Cooling towers are of course only water vapour, so as long as the visible emission of the central thin stack on a coal power station is white, it’s running clean.
I was always behind the curve of whatever the core game was on wow, so I was always trying to catch up to the guys who introduced me to it, never really had the time to do endgame stuff with them, because of having two little kids. By the time WOTLK dropped, I was PUGing a DK all the time because I was nowhere near the endgame where my buddies were. After that I became incredibly casual. Just questing the storyline of wherever I was. Dropped it and came back in classic. When Cata dropped on classic, with no era to play on with, and again, I was no where near cap the whole second time around I unsubbed. I have just rolled a PS and intend to casually bum around until my server falls over and I’ve maxxed out every char and class I want to.