I've had energy bars during long bike rides of a 3 hours or more and they work well, but like HC says they need to be taken with water.
I've come to realize that if I'm in shape, stuff like that isn't needed for quick energy any more. I've been quite successful eating some dried apricots or raisins for some extra energy during long workouts. Both are good sources of potassium.
Think of food as fuel for the body instead of feeding emotions