Renewable energies are sources of energy whose use does not affect, nor affect the natural resources available to man. These energy sources are regenerated after each cycle of use and, therefore, are inexhaustible.
While some renewable sources are available in large quantities and are not affected by exploitation by humans. A typical example of renewable energy is solar energy. The planet Earth is continuously irradiated by the flow of renewable energy that man can use or not.
There are other renewable sources, however, can become exhausted when the man exaggerates the use. These sources are called exhaustible renewable energy. For example, wood is a renewable resource because some trees are cut while others are born. However, if the number of trees cut is higher than those that are born, the excess of use will cause the progressive reduction of the forest over time, until it disappears completely. In this second case, excessive exploitation transformed a renewable resource into an exhaustible resource.
The main sources of renewable energy
It is the most known renewable source and is used to produce heat and, thanks to photovoltaic technology, to produce electricity.
It is the source of energy generated by the wind, by the continuous movement of the air masses. It can be transformed directly into mechanical energy (windmills) and indirectly into electricity (wind turbines). Wind energy is one of the oldest renewable energy sources. For millennia it has been the only source of energy for maritime navigation over long distances.
They are organic (biological) resources that can be used as fuels and / or fuels. For example, waste from agri-food processing can be used as raw material to produce thermal energy (heat) through combustion. Some organic substances (sugar, cereals, oils, etc.) can be transformed into biofuels.
It is the energy of the Earth and the heat coming from the subsoil. The temperature increases in the depths of the earth. In some areas the thermal difference between the superficial and the underground layers is greater and can be exploited to heat and create a natural circulation of liquids.
It is the movement of the masses of water. The main sources of hydraulic energy are generated by the natural cycle of water, waves and tides.
The sources of fossil energy (oil, coal, natural gas) and the nuclear source (uranium, plutonium) are, however, to be considered limited and non-renewable resources. They can only be used once and do not reproduce naturally so I can conclude by saying that these sources must be used with criteria and kept under control for the good of all …
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