Answer:
While ATP itself doesn't just generate energy from being present it for the most part does that probably seems confusing so I will clarify. ATP is a highly unstable molecule and without the assistants of anything its bonds will break. So you start with ADP once chemiosmosis is complete specifically the phosphorylation portion of it, Adenosine diphosphate because adenosine triphosphate. Basically a phosphate molecule is shoved on to ADP making ATP this last molecule is easily broken off, as I previously explained, releasing energy.
A simple explanation is what follows. When ATP loses a phosphate molecule becoming ADP energy is released.