In this case, our activation energy is simply this quantity here. It's the difference between the energy of the molecule found on this topmost portion of the hill and the energy of that reacting. This is the GIBS free energy given by Delta G with the symbol on top or simply Delta E A, where the A stands for activation. Now this topmost apex of the hill describes the energy of the transition state of this chemical reaction. And if you, if you recall from organic chemistry, the transition state is not something that exists for a very long time and that's because it has a very high energy value. As can be seen by the following diagram, this apex has the highest energy value in that reaction.