If I have an electrical AC generator producing 5000 watts at 220 volts but I only consume 3000 watts of power, what happens to the remaining 2000 watts?

Nothing, it is just potential energy, not used until needed. The 5000 is Maximum output that can be produced through the generating system. Like in your house, you have a 200 AMP box but may be drawing only 150, the other 50 is potential(available) energy. Good question, though, as electrical use is often misunderstood.

Another way to look at it... your car might be able to go 150 mph... but you are driving on a road that's got a 55 mph limit, You aren't driving around with your right foot to the floor, and your left foot on the brake to slow it down all at once. You are only using what you need to go 55.

You use what you need... but if the need ever arrose to go 150 mph... (like if you lived in Germany)... its there, you just aren't using it until you need it. It really didn't go anywhere..

ma and Smoothy answered your question dead on accurate. Me, I'm wondering if there's more to this question. Is it a homework question? Just my gut telling me there's more to this. But my gut has been known to be wrong.