What carbohydrate has more energy stored in its structure?

It depends on the type of carbohydrate. Simple carbohydrates (or sugars), such as glucose and fructose, are absorbed into the bloodstream and provide an immediate energy boost, and are the most quickly turned into energy. Other carbohydrates, such as starch, take more time to digest and are probably similar energy wise as protein or fats. However, as far as containing the most energy in a given amount, fats beat all carbohydrates and proteins by far.