What and where is energy?

Energy is electricity/emf coexisting with matters. All mechanic works are electrostatic force at working. Push a car, the pressure between hand and car is the repulsion force between negatively charged atoms' surfaces on the hand and car. 

We use coal, oil, gas to produce heat/chemical reaction, but energy are not stored in those matters. Otherwise, why we don't use gas and coal to produce more heat?

Oxygen is the source of energy in chemical reactions. All life forms use energy from oxygen to survive, so called fuels just like a trigger to release it from oxygen atoms.

How does oxygen carry and store energy? .I have not totally figured it out yet, but getting closer.

We must know how atoms are constructed before we can make sure the rest everything involved atoms.

Suppose we seal a charged ball inside of a same charged shell, it can carry and store electric energy. The ball can oscillate inside carrying kinetic energy.

Suppose the shell has a opposite charged outer shell, it attracts the ball, the inner shell repel the ball, so the ball will oscillate off center. If you shake the shell/atom, the ball will bounce back and forth inside at force direction. In theory, it can carry infinite energy, depends on how much we put in. 

Now if we put two atoms next to each other, the two balls will have double amount of attraction force act on them, so they will be trapped closer to the inner shell. store some kinetic energy into potential energy. Now if another atom can going between the two atoms, the two atoms gets apart, the ball feels less attraction force, released from locking, bounce inside harder, carry more kinetic energy, release to other lines of sight atom.in the form of contact or electric radiation. 

Notice this simplified atom, in fact, there is a floating charged fluid over the outer shell, it attracted by the inner shell, repelled by the outer shell, also oscillating at force direction.

The floating fluid on atoms are the carrier of light energy. The oscillation frequency governs matters color, the force strength is voltage.