Energy is a resource used by the player to perform checks.
For example, a player may observe an object but not interact with it unless they have the required energy.
If a player has the required energy, they may roll dice to see if they're able to perform the action successfully. Upon a successful check, the player will receive more experience points.
Once a player gains a certain number of experience points, they will "level up" and be given bonuses such as extra energy or "power-ups" to their dice rolls (i.e: 1d4+1 instead of just 1d4)