What is renewable energy?
Renewable energy sources (RES) are based on natural, ecological and inexhaustible resources. They have been developed in such a way that they guarantee not only emission-free production of electricity and heat but also endless possibilities of use. Over the years, efficient methods of generating electricity and heat from these environmentally friendly renewable sources have been developed. All of them provide what coal and similar energy sources do not, i.e. environmental friendliness and the certainty that there will simply be no shortage of them. However, each has its own specifics, slightly different characteristics, works in different places and on different scales. What are renewable energy sources and what are their characteristics?
The most commonly mentioned renewable energy sources are:
Energy from the sun can be used in two ways – to generate electricity or heat. The first is done by using solar collectors, which absorb solar energy and in the form of heat transfer it further to the installation, where it is converted to efficient use. The second method, photovoltaics, involves the installation of cells made of semiconductor material (usually silicon), which extract the energy of solar radiation and convert it into direct current. Did you know that covering 0.3% of the planet’s surface with photovoltaic panels would be enough to meet the energy needs of people around the world? That’s about the size of Sweden, so very small, right?
2. Wind energy
The use of wind energy is based on the operation of wind turbines, which convert the kinetic energy of the wind into electricity. How it works. Wind farms consist of individual turbines. A wind turbine consists of 3 main components: a tower, a moving nacelle and a rotor, i.e. a structure of blades that rotate to generate energy. All thanks to the wind, which is becoming an increasingly popular renewable energy source, being one of the two most used.
3. Hydropower
Water is another force and a huge energy potential. Hydropower is based on harnessing the power of flowing water. Through systems of dams, barrages, turbines and streams, kinetic energy is generated from the movement of water and converted into electricity. This field also includes current and tidal energy, which is based on the use of regular changes in water levels in the seas and oceans. These methods are used in special tidal power plants, but so far they are not very popular, largely due to the high cost of producing such energy.
4. Biomass energy
Any substance of animal or plant origin that undergoes a biodegradation process can also be used to generate RES energy. This is called biomass. Here the key is the process of photosynthesis and conversion of solar energy in the process of combustion into energy that can be effectively used. There are different types of biomass: solid (e.g. wood, plants), liquid (so-called biofuels, e.g. from rapeseed) and gaseous (so-called biogas). A more popular application of biomass is heat production, but recently more and more energy is also generated for electrical purposes.
5. Geothermal energy
The last renewable source is geothermal energy, which is the energy from inside the earth, using the heat of water and rocks beneath the surface. It is most often associated, and rightly so, with Icelandic geysers. Geothermal energy is one of the most difficult sources of renewable energy to obtain due to the fact that the deposits are located deep underground (even up to several kilometers deep). The resources are extracted by means of boreholes from which hot water or steam is drawn, which is then converted to energy for use in a geothermal power plant. Geothermal is used primarily as a source of heat energy, but it is also possible to generate electricity.
All renewable sources have in common that during energy generation and production no harmful substances are emitted into the atmosphere, so their use does not affect climate change and the greenhouse effect. They all belong to the so-called “green energy”, which means that they are natural, usually easily accessible (although it depends on the type of source) and cheap, if appropriate methods of obtaining them are developed.