Energy is a Greek word that comes from the words “in” and “ergon” meaning “action.” For this reason, we say that energy is the ability to work, forces, movements. We can not see, only discovered its effects.It is what permits it to almost everything in the universe: life, light, electric current, the career of a car, a flame, noise or wind. The law of conservation of energy says that it is not lost but transformed. It can not be created or destroyed, and when we believe will correct itself has become another form of energy. ENERGY SOURCES The energy comes from energy resources or the “energy” that nature provides. Energy sources are classified into renewable and nonrenewable. The non-renewable energy sources are found in limited quantities in nature, whose training has taken place over millions of years is that energy resources will be depleted sooner or later, and this depends on the intensity with which they explode.For example, fossil fuels like coal, oil and natural gas, providing heat of combustion. Radioactive minerals, which undergo a process of disintegration of their atomic nuclei such as uranium and which lead to heat of combustion. It is called renewable energy sources to the energy obtained virtually inexhaustible natural sources, some by the vast amount of energy they contain, and others because they are able to regenerate by natural means. For example: The sun provides solar energy. – The wind or moving air, which causes wind. – Water from rivers or seas, whose movement generates hydropower, inone case, and tidal energy, on the other.- Volcanoes, geysers and hot springs, giving rise to geothermal energy (the interior of the Earth) .- The living organisms, which, through suitable chemical processes, it draws power from biomass. – Hydrogen, the most abundant gas in the universe, whose combustion produces heat energy. TYPES OF ENERGY Energy can manifest in different ways: in the form of motion (kinetic) of position (potential), heat, electricity, electromagnetic radiation, etc..Depending on the process, the energy is called: ENERGY SOURCES The energy sources we can split into: Renewable sources are those that nature renews quickly, and we can get energy continuously. Non-renewable sources, are those found on Earth and depleted with use, because the quantities are limited. Renewable Sources Hydropower is energy obtained from the water fall from a height to a level below what this causes the movement of water wheels or turbines.