Any idea what this could be?
 

I'm hearing one hell of an annoying buzzing sound coming from my engine bay. It sounds like it is around the alternator but I can't narrow it down. Any clue what the buzzing sound could indicate?

it could be your alternator.

or tensoiner, or water pump bearings etc.... You need to open the hood with the car running to see if you can get a better idea of where its comming from. also could just be bad belt. spray some wd40 to see if it stops if it does the belt is doing it and would probibly help to get some belt dressiing from autozone etc...

I have a squeaking noise and its the tensioner pulley so look out for that. MT#1customer had a good idea, get a pipe and listen through it to see if you can narrow down what it is.