Final answer:
As a human, Edward would use glycogen as his primary source of energy to perform the quick action of saving Bella.
Step-by-step explanation:
If Edward were a human (not a vampire), the source of energy he would be using when he saved Bella's life would primarily be glycogen. Glycogen is a stored form of glucose that is converted to adenosine triphosphate (ATP) for short-term use by all cells as described in animal bioenergetics. During a rapid and intense action such as racing to save someone, the human body would tap into this glycogen stored in the muscles to get a quick supply of energy.