According to Wikipedia, the definition is: “a scalar physical quantity, an attribute of objects and systems that is conserved in nature. In physics textbooks energy is often defined as the ability to do work or to generate heat.”
“Conserved in nature” would also mean conserved in the universe. Nature is part of the universe.
Is the universe then made up of different energies?
“Science shows us that everything is made up of energy and exchanges that with everything else at all times in a most complex way. It is the building block of all matter. The same energy that composes your flesh is the same one that composes the bricks of your house and the trees outside. It is all the same. It is constantly at flow, changing form all the time. This is a very simple explanation of a rather complex thing.”
Everything in this universe is made up of the same stuff. It is just present in different forms and shapes.
Everything is energy
If we go below this level - to a subatomic level - scientists have shown us through quantum physics that everything at this level is pure energy. Hence humans are pure energy. Everything in this universe is made up of energy including ourselves. From a spiritual viewpoint we are deathless souls within a physical body - a particle of the Divine, of the Creator, The Source - God.
Bob Proctor from the movie The Secret who has been practicing the Law of Attraction and other Laws of the universe for 45 years also talks about everything being energy.