Energy

What is it?

The water cycle, triggered by the evaporation of the Earth’s water, the formation of clouds and rain, provides mankind with the most extraordinary renewable energy source, the second after biomass. Its origin is once again the sun, the radiation of which causes evaporation. Although only 0.33% of solar energy received by the Earth leads to rainfall, it is still a remarkable amount of energy (see image).
Water includes two types of energy: potential and kinetic.

Potential energy
Both when it falls down as rain and when it comes out of a spring, water is forced to go “downwards” due to force of gravity. We all can see the energy of a waterfall; the higher the jump, the more energy will be produced by the water when it falls. Therefore, the higher the water is located with respect to the point of arrival, the more the energy that can be potentially developed. Potential energy is therefore the energy of the water mass at rest, according to the initial position of water and its point of arrival. It corresponds to the energy contained in the glaciers and natural or artificial basins located at high altitude. 

Kinetic energy
Water kinetic energy is the energy of a moving water mass and corresponds to the energy contained in the water of rivers, water streams and the sea. It depends on the speed and the volume of the moving water. Hydraulic machines transform water movement into mechanic energy. It is simple to convert mechanic energy into electric energy.