In your example energy is conserved and so the total energy will not change.
Total energy = kinetic energy + potential energy
At the highest point, the pendulum stands still momentarily before it starts moving downwards again.
Total energy = 0J + 622J
At the lowest point, I will assume the potential energy is zero.
Total energy = kinetic energy + 0J = 622J
kinetic energy = 622J
Since the total energy can't change, the potential energy must have been converted to kinetic energy.
