What are renewable energies? Definition and simple explanation:
Under the term renewable energy All energy sources that are derived from renewable raw materials or sources are grouped together. This means that they are either inexhaustible, continuously available or regrowing regularly. Renewable energies enable a sustainable use of resources and are therefore considered as an environmentally friendly alternative to fossil fuels. Many sources used for the production of renewable energy are produced under the influence of solar radiation, ie they are either direct or indirect forms of solar energy.
The most widely used sources of renewable or renewable energy sources include solar radiation, the kinetic energy of wind (wind energy) and water (hydro), geothermal or geothermal energy, and tides. Renewable resources are also suitable for generating energy. These are grouped under the name biomass and can be of plant or animal origin.
Forms of renewable energy production
Probably the most important form of renewable energy is the direct use of solar radiation. This type includes the so-called solar thermal and photovoltaic. Solar thermal energy is a technique that uses solar collectors to capture solar radiation and convert it into heat. Solar thermal systems can be installed on buildings of different sizes and store energy for the treatment of hot water. Solar thermal power plants, on the other hand, work with heat engines that convert solar thermal energy into electrical energy. Electricity is also obtained through a process known as photovoltaic. In the process, so-called solar cells, in which the light rays are captured, produce electrical energy.
There are also several options available for the indirect use of solar energy. Wind energy, for example, is caused by the effect of solar radiation on the air pressure and has been increasingly converted into electricity in wind turbines for a few decades. The kinetic energy of water, which is used in different types of hydropower plants, depends on the influence of solar and wind energy. The kinetic energy of the water is used in ordinary hydropower plants, in wave power plants or hydroelectric power plants for the production of electricity. Plants grow by the action of solar radiation and are used in different ways as biomass to win bioenergy. As regenerative plant sources (phytomass) for bioenergy, we use culture and oil plants, wood, household and industrial biowaste, grass and hay. Animal waste and manure (Zoomasse) can also be used as raw materials for bioenergy.
Geothermal energy is considered the most important form of renewable energy that does not come either directly or indirectly from solar energy. Geothermal energy is a process that uses high temperature geothermal energy from different layers of the earth as a source of electricity generation. Among the hydroelectric power plants, the so-called tidal power plant produces a form of renewable energy whose source (ebb and flow) is not influenced by solar radiation, but by the action of the moon.
Advantages and disadvantages of renewable energies
Solar thermal energy, as a continuous form of energy production, is considered the most environmentally friendly form of renewable energy. Once installed on a building, CO2 emissions are significantly lower compared to power plants. This is mainly due to the fact that the energy produced by the solar thermal system for hot water treatment is used directly in the building. Transport routes and the associated consumption of fuel account for the same as the construction of production facilities. The use of all other forms of renewable energy is linked to the construction of power plants that carry a certain amount of CO2 and change the surrounding ecosystem. Nevertheless, modern hydroelectric power plants, wind turbines and biomass treatment plants are much more environmentally friendly than the use of fossil fuels, since exhaust pollution is generally lower. As extraction and use often takes place regionally, renewable energy enables economic independence from states that have large resources of fossil fuels.
Critics point out, however, that many forms of renewable energy have a relatively low power density, but at the same time make the construction of large facilities necessary. Hydropower plants or wind farms not only change the landscape, but sometimes have a significant negative impact on the flora and fauna. In addition, the energy sources are inexhaustible, but often subject to seasonal fluctuations. In the case of biomass, agricultural limits must also be considered. For crops and crops, land must be created, which in turn is associated with a significant change in the landscape.