What compound can be made from glucose and serves as long term energy storage?

The answer is: fats/lipids.

Lipids store 9 calories of energy per gram while the other sources of energy store less. For that reason, lipids serve as a more compact way to store energy and our body only tends to use it if it runs out of carbohydrates stored That only happens if you don't eat for long periods of time and the body breaks them down as a source of glucose for cells use.