What might cause 2011 BMW 328i loud whining noise?

A loud whining noise in a 2011 BMW 328i could be a variety of things, including the alternator, a bearing with issues and more. While a whining noise is most notorious to be caused by timing belts, note that this car does not have one of those. It comes with a timing chain which does not generate the same whining sound of a belt, as it drives. Listening to the sound and trying to figure out what direction it is coming from will narrow down the possible culprits. If You have to listen for the sound while operating the vehicle, You need to avoid removing Your attention from the road.