People have always looked for ways to control energy for their own use.  For example, the steam engine allowed full control of a powerful energy source:   expanding steam.  People could control the direction, amount of power, and the duration of the energy output.
 
Since the invention of the steam engine, people have developed many new methods of controlling energy.  We control energy for transportation, heating, and cooling.

Every energy control system has three parts:

1. The original source of energy.
2. All the conversions the energy goes through, including the transmission (moving) of energy from one place to another.
3. The eventual use of the energy.