Renewable energy is that energy that comes from practically inexhaustible natural sources. They are considered inexhaustible either because of the large amount of energy they contain or because they can regenerate naturally.
Among the main advantages of renewable energy we highlight the following:
- Renewable energies are respectful with the environment and do not pollute. They do not generate greenhouse gases and do not contribute to climate change.
- Renewables are safer and pose fewer health risks than other non-renewable energy sources. The more energy generated by clean energy, the more fossil energy will need to be generated.
- In most cases they are easy to dismantle and there is no need to guard their waste, as in the case of nuclear energy, for example.
- They allow energy to be obtained without depleting natural resources. Renewable energies, by definition, come from sources that are inexhaustible and that allow obtaining an energy benefit without depleting resources, as happens with energies related to fossil fuels.
Examples of renewable energy
Renewable energy can be used to generate electricity, but it can also be used in other applications. Here are some examples of renewable energy:
- Generation of electricity using photovoltaic solar energy panels.
- Thermal solar energy installations for heating.
- Pool heating by solar energy.
- Thermal centers using geothermal energy.
- Heating systems using geothermal wells.
- Electric power generation through wind farms.
- The use of hydraulic energy through swamps for the generation of electricity.
- Sailing boats.
- The flight of gliders and gliders without a motor, which take advantage of updrafts.
- Photosynthesis is a way for plants to take advantage of solar energy. In this case, who benefits are the plants, but it is still an example of renewable energy.
In a more generic way, renewable energy can be classified depending on the natural resources that are used.
What are the types of renewable energy?
The main sources of renewable energy are the following:
- Solar energy, which uses electromagnetic energy from the Sun.
- Wind energy, which takes advantage of the force and speed of the wind.
- Hydraulic power, which uses the potential energy in the water. Water mills, hydroelectric plants, etc.
- Geothermal energy, which takes advantage of the heat inside the Earth.
- Biomass, based on the use of organic materials of plant or animal origin.
- Tidal and wave energy, which uses marine currents and the movement of tides and waves.
What is solar energy?
Solar energy is energy that directly harnesses solar radiation. Although the Sun does not have an inexhaustible life, it is estimated that the Sun's life is millions of years. So, on a human scale, solar energy is considered an inexhaustible source and solar energy is renewable energy.
We distinguish two forms of use of solar energy: thermal solar energy and solar photovoltaic energy.
- Thermal solar energy. The use of solar thermal energy consists in using the heat energy obtained through the Sun's radiation to heat a fluid that, depending on its temperature, is used to produce hot water and even steam.
- Photovoltaic solar energy. The use of photovoltaic solar energy is carried out through the direct transformation of solar energy into electrical energy through the so-called photovoltaic effect. This transformation is carried out using photovoltaic cells that are made of semiconductor materials (for example, silicon) that generate electricity when they are hit by solar radiation.
What does wind power consist of?
Wind energy is a renewable energy source because the wind is an inexhaustible source. To a certain extent the wind is a consequence of solar energy because the wind is displaced by differences in pressures and temperatures caused directly or indirectly by the Sun.
There are two types of wind installations:
- Isolated wind energy installations, to generate electrical energy in remote places for self-consumption. It is very common for these installations to be combined with photovoltaic panels.
- Wind farms, formed by a set of wind turbines, to sell the electricity generated to the grid.
Current technological development, as well as a better understanding of the wind conditions in the different areas, is allowing the implementation of wind farms connected to the electricity grid in numerous regions around the world. Furthermore, improvements in the aeronautical design have considerably increased the energy efficiency of these facilities.
What is hydraulic energy?
Hydraulic energy is a type of energy that harnesses the potential energy of water to obtain mechanical work. If we use this mechanical work in the form of kinetic energy to drive a generator, we obtain electrical energy. In this case, we will be talking about hydroelectric power.
Hydraulic energy is considered a renewable energy because the water cycle remains invariable and is inexhaustible. As in wind energy, the water cycle (and therefore hydraulic energy) has a strong dependence on solar energy.
Hydraulic energy harnesses the potential energy of the water from a jump to produce electrical energy. The water moves a turbine whose rotational movement is transferred by means of an axis to an electricity generator. The main advantage of hydraulic energy is that energy can be stored in the form of potential energy and electricity can be generated at times of demand.
When the power of these generators is less than 10 MW, it is called mini-hydraulic energy.
There are basically two types of hydroelectric plants:
- Flowing water hydroelectric plants: Those hydroelectric plants that capture a part of the flow circulating through a river and take it to the plant to be turbined and generate electrical energy. Later, this flow is returned to the river bed.
- Hydroelectric plants at the foot of the dam: Those hydroelectric plants located downstream of the reservoirs intended for hydroelectric uses or for other purposes such as supplying water to towns or irrigation. They have the advantage of storing energy (water) and being able to use it when it is most needed.
What is obtained from biomass?
Biomass is a renewable energy source based on the use of organic materials of plant or animal origin, including the products and by-products resulting from its transformation. Under the name of biomass, energy materials of many different kinds are collected: forest residues, woody and herbaceous agricultural residues, residues from various industrial processes, energy crops, organic materials contained in urban solid residues, biogas from livestock residues or biodegradable residues. industrial facilities, urban wastewater treatment or landfill, etc.
Biomass applications can be divided into two groups:
- Domestic and industrial applications that work through the direct combustion of biomass.
- Applications linked to the emergence of new resources and new transformation techniques, such as gasification and biomass pyrolysis.
What does tidal and wave energy consist of?
Seas and oceans are huge solar collectors from which energy from diverse sources (waves, tides, and thermal gradients) can be extracted.
The energy released by seawater in its rising and falling tidal movements (ebb and flow) is harnessed in tidal power plants, passing the water through hydraulic turbines.
Obviously these maritime movements are inexhaustible so we can consider tidal energy a renewable energy.
The energy of the waves is produced by the winds and is very irregular. This has led to many types of machines for its use.
Lastly, ocean thermal energy conversion is a method of converting the difference in temperature between surface water and water 100 m deep into useful energy. For use, a difference of 20 ° C is sufficient. The advantages of this energy source are associated with the fact that it is a permanent and environmentally benign thermal jump.
What is geothermal energy?
Geothermal energy is the manifestation of thermal energy accumulated in rocks or waters that are at a high temperature inside the earth. Geothermal energy is the branch of science that explains this phenomenon.
The large amount of heat and thermal energy stored inside the Earth is so great that the exploitation of this energy resource has practically no effect on the internal energy of the Earth. For this reason it is considered a renewable energy source.
For use in areas with special thermal conditions, for example, volcanic areas, a fluid is circulated in them that transports heat energy to the surface in the form of heat accumulated in hot areas.
The main advantage of geothermal energy is that its environmental impact is minimal, and it has energy yields that allow it to compete with fossil fuels such as oil, coal or natural gas. On the other hand, the main disadvantages of geothermal energy are that they require large investments and that geothermal fields are relatively scarce and are often located in unfavorable areas.
- Renewables 2007 Global Status Report (PDF)
Last review: March 15, 2020