Although they are not the same, they are commonly associated with clean energy , since it is sought that the development of energy , in the future, be ecological. It is the counterpart of non-renewable energies known to be polluting ( fossil fuels , gas, oil, nuclear energy , etc).
What are renewable energies?
They are those that are produced taking as raw material the natural sources that are not exhausted, such as the sun (solar energy), the waves and tides (tidal and hydraulic energy), the wind (wind energy), the heat of the earth (energy geothermal), the power of water (hydraulic energy), the chemical potential within biological substances (biomass), etc.
They have come as a viable alternative to fossil fuels or hydrocarbons since they allow electricity to be generated but in a natural, clean, sustainable way and that are generally capable of being renewed over time .
Types and examples of renewable energy
Since the sources, the procedures and finally the uses of each one are different, we will review:
- SOLAR ENERGY : It consists of capturing the rays coming from the Sun , to take advantage of its heat capacity ( thermal energy ) or to take its light energy and convert it into electrical energy . This is done through solar panels that can work as solar collectors and use their heat (example: solar heater ) or photovoltaic panels (to produce electricity).
- WIND ENERGY : They consist of capturing the power of the wind that arises from the constant currents of air; A wind farm (an area with optimal conditions where at least twenty wind turbines are installed ) allows us to transform wind energy into mechanical energy , or directly into electrical energy using wind turbines . The wind is a source of energy that has been used for a long time (for example in sailing) and that is inexhaustible. The logic of this source is simple: The wind makes the blades of the turbines move, the movement is transmitted to a generator that produces electrical energy.
- Geothermal energy: It consists of taking advantage of the potential energy that exists in the Earth , more specifically the heat of the ground. The subsoil and the heat it contains are also part of renewable energies. In some areas of the earth, the difference in heat between the most superficial layers and the subterranean is increased and can be used to heat and generate a natural circulation of fluids . The potential of this kind of energy can be seen in geysers and volcanoes. At an industrial level it is also usable, since water vapor, when it passes through a turbine that contains a generator, allows electricity to be generated.
- HYDRAULIC ENERGY : Water falls from a certain level of height also produce energy. The descent of water generates kinetic energy , the speed makes hydraulic turbines move and through generators it is converted into electricity. The power plants located under the dams or along the course of the rivers make the movement of water become electricity, constituting the main source of renewable energy throughout the world.
Renewable energies with less development
The aforementioned are the best known and most developed sources of renewable energy worldwide ; below we will mention others in current development and in search of expansion.
- BIOMASS : These are biological resources that can be used as fuel to generate thermal energy . For example, the waste obtained in the agri-food industry can be used to produce heat through combustion . Some organic elements can be converted into fuels, such as: Cereals, sugar, oils, agricultural waste, etc.
Plants capture solar energy through photosynthesis. The energy accumulates in wood , plants, fruit shells and other residues. When they burn, the chemical energy stored inside them is released, usually in the form of thermal energy .
- TIDAL ENERGY : It consists of capturing the movement of the tides in order to take advantage of their kinetic energy. The difference between the tides is generally used (the water is taken when the tide is high, it is released when it is low), and with the movement and by means of an alternator , electrical energy is obtained.
- HYDROGEN: Hydrogen is an element that is found abundantly in nature, but it is not found in its pure state. To obtain it, other energy sources are required. Once this element is obtained, energy can be transformed through a technology similar to that used in the manufacture of batteries.
- NUCLEAR ENERGY : It is important to mention that nuclear energy is non-renewable , but if we maintain the fusion and fission processes and change the Uranium for hydrogen , then it would be a renewable energy, but not clean, since the process of generating atomic energy It usually generates waste.
Characteristics of renewable energy
- They are generally clean energies – There are exceptions such as nuclear energy (when Uranium is exchanged for Hydrogen) or biomass energy (which does not have a production process, but is not too clean in its consumption).
- They are environmentally friendly energies – Since they are based on inexhaustible sources of energy, then they do not generate scarcity of said raw material; Related to the previous point, its production is usually clean.
- They are vast energies – Singularly, most renewable energies (solar, wind, hydraulic, tidal, biomass) could supply energy to the planet (and there would be plenty of energy potential); If we combine them, it is even simpler.
- They are currently (2020) in a less developed stage – Compared to other energy sources (such as fossil fuels or nuclear energy), they are usually in a lower stage of development, they are usually more rudimentary (compared to what they are going to be). in 10 or 20 years) and do not usually have economies of scale (or at least not so easily); They are far from their maximum splendor.
- They are new – Except for wind power (which was used roughly and inefficiently in sailing), they are all new energies and require advanced engineering developments.
- They are more expensive – Due to the two previous points (less development and more innovative), their production is still slightly more expensive than traditional ones.
- They are the future – For all of the above.
Advantages of renewable energies compared to fossil energies
- Making a comparison between fossil fuels ( coal or oil ) and renewable energies, the latter have fewer carbon emissions, can be recycled and are respectful of nature.
- Hydrocarbons emit gases that cause the greenhouse effect , contributing to global warming. Renewable energies are essential to stop global warming and climate change, since they do not emit gases.
- Renewable energies are indigenous and can be exploited locally. This reduces the cost of transportation that is necessary when exploiting fossil energies.
- The availability of renewable energy means that it has less price changes , unlike gas or oil.
- The potential is unlimited in renewable energies compared to the limited resources of hydrocarbons.
In short, renewable energies do not pollute, do not run out, stop the greenhouse effect, benefit the economy, allow savings, are sustainable, meet demand, etc.