Renewable energy derives directly from energy sources that are part of the physical structure of our planet and that, therefore, are constantly reproduced by means present in nature. In other words, they cannot be exhausted.
Renewable energy sources can be detected in the sun, in the air, in the earth’s depths and in the oceans. These sources are often referred to as “alternatives”, as they act as valid substitutes for fossil fuels such as oil and coal.
However, this particular property does not make them 100% safe for the environment. For example, dams can exploit the power of water but, at the same time, harm fish and aquatic fauna.
Furthermore, wind turbines use wind power to create electricity.
Nevertheless, the environmental impact deriving from their production and their action is not negligible.
However, it should be pointed out that renewable energies produce an environmental footprint far inferior to fossil fuels. This is the main reason why they are so important and, if exploited correctly, they can make the Earth an increasingly less polluted place.
Climate change is there for all to see.
Consequently, choosing a greener road will improve the global environmental situation, ensuring a better state of health for all individuals. What is environmentally friendly is increasingly becoming a friend of the economy (both for citizens and for companies). In many parts of the world, solar and wind power are less expensive than fossil fuels. Their cost continues to fall from year to year.
But how exactly do renewable energies work?
Here are some sources of alternative energy sources that can be used to help the world become a greener place and reduce global warming. The sun, as we will see, has an important role in many of these.
Among renewable energies, this is probably the best known. The development of multiple technologies has made it possible to exploit solar energy to produce electricity and heat. Some examples are lighting, hot water and, although it may seem paradoxical, cooling systems for industries. Photovoltaic systems use cells to capture solar energy and convert it into electricity. Furthermore, solar thermal systems allow water to be heated in buildings and companies. Finally, state-of-the-art architectural projects passively exploit the sun as a light source, for heating and cooling. Homeowners, corporate owners, and government agencies can take advantage of solar energy in many ways: by installing, for example, on the roof a domestic photovoltaic system or commercial solar panels.
The wind can be considered a particular form of solar energy: the constant heating or cooling of the atmosphere causes the formation of winds, as well as the earth’s rotation and other topographical factors. If capturing the wind can seem like a chimera to many, the turbines and wind turbines have been designed for this purpose. Thanks to the currents of the winds they are able to produce electricity. If, on a large scale, the most important systems are used to produce energy useful to many institutions and organizations, in some areas windmills are still used locally to operate farm machinery. Electric turbines can be integrated with the public energy network. When the wind blows, the system compensates for the need for electricity that would otherwise be provided by the appointed body.
Among the renewable energies we can also include the geothermal energy, which uses the heat produced internally from the Earth. This heat is taken from the surface, from hot rocks or from water reserves under the earth’s surface. Geothermal plants exploit these heat sources to generate electricity. The use of geothermal energy can take place on a large scale to heat commercial buildings. Its direct exploitation includes: heating of manufacturing plants, offices and greenhouses and be used for various industrial processes (for example, milk pasteurization).
Its discovery dates back to many centuries ago, when the energy of the water was used for the functioning of mills and sawmills. Today, the kinetic energy derived from the flow of water is exploited differently and converted into electricity. The most well-known system is certainly that of dams, where water is collected in a basin and then released and passed through turbines which, in turn, will produce electricity. The power stations that carry out th
Processes are called power plants with accumulation plants, in which water is recycled between the lower and upper basins to control the production of electricity between the periods of low and high demand. A second hydroelectric system can be identified in flowing water plants, where a portion of the river is diverted into a canal and made to flow through turbines that rotate thanks to the speed of the water. A third system is that of basin power stations. In this case the water is accumulated in a reservoir or artificial lake thanks to a dam, to then be sent down to forced ducts which, in turn, conduct the water through turbines responsible for the production of electricity. At the end of the path the water is returned to the river flow, unlike the first system where the water is returned to the upper basin.
Energy of the Oceans
The renewable energies produced by the oceans are two: the first, thermal, comes from the heating of the water by the sun and, the second, from the motion of waves and tides. The “mechanical” energy of the ocean exploits the waves and the flow of the tides caused by winds, the earth’s rotation and the gravitational influence produced by the moon.
While the five just analyzed foresee a direct exploitation of natural processes, the renewable energies that follow must be produced mechanically.
Bioenergy is produced from biomass, useful for creating heat, electricity and liquid fuels such as ethanol and biodiesel. Biomass is an organic residue that derives from plants or animals. There are different systems that allow you to generate electricity from biomass. Some that burn them directly and others exploit the methane produced by the natural decomposition of organic matter.
Companies and organizations that transport people or goods can convert their vehicles into vehicles that use biofuels. Manufacturing industries, by burning biomass, are able to produce the heat channeled into the turbines to produce electricity. In some cases, the process can have a dual purpose: to produce electricity and heat the structure. Paper mills for example, by burning wood residues, are able to produce electricity and heat for heating. Farms can convert waste produced by cattle into electricity using small modular systems. Cities have the opportunity to exploit the methane gas created by the anaerobic digestion of organic waste in landfills and use it as fuel to generate electricity.
Hydrogen: High Energy, Low Pollution
Hydrogen is the simplest and most abundant element on Earth, even though it is not naturally present in the form of gas. It can be found in organic compounds such as hydrocarbons (gasoline, natural gas, methane and propane) and water (H2O). Hydrogen is also derived in certain situations from certain algae and bacteria using the energy of the sun. It also has a high energy potential and produces almost no pollution when burned. Liquid hydrogen has been used since 1950 to launch Shuttle and other space rockets into orbit. Fuel cells are used to produce electricity through the chemical energy produced by combining oxygen and hydrogen for water production. It should be noted that the marketing of these cells is still limited given the high costs.