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Renewable sources of energy, there is a lot of talk about it but the clarity is not as much, at least for those who do not chew it daily even if it could benefit from it every day. Daily but long and decisively, even for posterity.

Renewable and non-renewable sources

The renewables they usually are natural and inexhaustible, in the sense that they produce energy that is regenerated in a short time if we think in the time scale of "geological eras", comparing ourselves with the duration of a human life. There are also renewables that are exhausted, for example, forests, but they are exceptions, but the fact that they do not enter polluting and / or climate-altering substances, CO2 above all. In fact most of the renewable sources of energy is considered clean, a clean alternative to that produced by traditional fossil sources, non-renewable and which emit into the atmosphere.

Having said that, we can conclude that the renewables they are truly invaluable resources to obtain energy by reducing to minimum environmental impact.

It is only right, before seeing what the renewables, specify that renewable, sustainable and alternative They are not the same thing. One subset of the other, or they intersect. Let's be clear, now that we have defined the renewables, it should be explained that the sustainable energy sources are those that also imply sustainable development, assessed by also looking at the aspect of the efficiency of energy uses. Renewables can be sustainable.

The alternative sources of energy on the other hand, they are all "non-fossil" ones, but not necessarily renewable and even less sustainable. The alternatives are also part of the alternatives renewables but they are not the only ones, to keep them company in this category, for example, there is also thenuclear energy.

Renewable sources: what they are

The distinction, dutiful, and the above definitions are official described in a European legislation (Directive 2009/28 / EC) and also for our country which, receiving it, understands the following as renewable energy sources. Wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydraulics, biomass, landfill gas, residual gases from purification processes and biogas.

Renewable sources of hydroelectricity

Hydroelectric energy is among the oldest renewables, the strength of the water is obtained: lake, river or artificial basin, the pressure and kinetic force of the water flow, once conveyed in pipelines can, can be transformed into a generator that converts it into electricity. The first to think about it were the ancient Egyptians building the first dam 6,000 years ago, on the Nile, then came the mills and much more. Today the renewables of hydroelectric power contribute about 18% to world production.

Renewable sources of geothermal energy

It is about geological sources which have a high temperature and produce a type of energy considered renewable, if evaluated in a short time. To be exploited is the natural warmth of the Earth, naturally produced by nuclear decays of some radioactive elements it contains: uranium, thorium and potassium.

The plants that exploit these renewables, called geothermal, can have a vertical probe or a horizontal probe and are used for heating, cooling buildings and the production of hot water. Also curious is the use of geothermal water at low temperatures to water in greenhouses or to irrigate in cold areas, with a climate-conditioning effect. Today thegeothermal energy today it constitutes less than 1% of world production.

New renewable sources

The acronym is NFER, they are new renewable sources of energy technologies for which technologies are being developed.These include, for example, advanced biomass gasification, biorefining technologies, thermodynamic solar power plants, geothermal energy from hot-dry-rocks and the exploitation of ocean energy. Italy lags behind other countries such as Germany, Japan and other Northern European countries, but we are confident of how our country often reserves surprises in the last mile.

Renewable sources of solar energy

Inexhaustible, clean and immediately available, thesolar power it is very advantageous: as long as there is sun there is hope, in short, and there will be renewable sources of energy. The amount of solar energy that reaches the earth is almost ten thousand times higher than that used in the whole world, we currently know how to exploit it to generate electricity, with photovoltaics, or to generate heat, with solar thermal.

For the first aspect, there is a lot to do, especially in Italy which seems to have lagged a bit behind in the development of photovoltaic panels often integrated into buildings, alternatively positioned in power plants connected to the electricity grid. In our country the most frequent are medium-large plants (from 100 kW and up to a few MW) connected to the electricity grid. At the moment there are no conditions for real competitiveness between renewables, more technology is needed and the aim is to integrate photovoltaics into buildings.

As for solar thermal and thermodynamic there are solar heating systems, namely solar thermal collectors that collect the radiant energy coming from the sun's rays and then heat the water in the house, swimming pools or entire rooms.

Renewable sources of wind energy

The renewable sources of wind energy are the winds: their kinetic energy, exploited thanks to wind turbines, is transformed into other forms of energy, electrical and mechanical, but above all in the former through wind farms. The data provided byIEA (International Energy Agency) tell of a growing trend for these renewables, so much so that we are optimistic and hope that in 2020 this road will be able to supply 20% of the electricity required worldwide, reaching 50% in 2050.

Renewable sources of energy from biomass

Waste materials of organic, plant and animal origin are possible renewable sources of energy from biomass, clean energy and also immediately usable. The European Community specifies that it is to be considered renewable only when "biomass" is considered the "biodegradable fraction of products, waste and residues of biological origin from agriculture, forestry and related industries, including fishing and aquaculture, as well as the biodegradable part of industrial and urban waste ".

On the other hand, if when we burn biomass we still replace it with new biomass, we do not increase the concentration of CO2 in the atmosphere. In the exploitation of these renewable sources of energy Italy has not made great strides so far, despite the high potential we have, it is Brazil that stands out and excel. His is one of the largest programs forrenewable energy of this type known to the world.

Renewable sources of marine energy

I am in the sea renewable sources of marine energy and we do not think of anything strange, I am referring to the wave motion, simply, for example, or to the movement of the air above the waves, the tides or the difference in temperature between the bottom and the surface. There are various ways to use our seas such as renewables, just as varied are the technologies required to exploit these potentialities offered by the sea, today these are complex processes and, more than anything else, expensive, for now. Italy has good examples to show the world in this field, also thanks to the great sea that embraces it.

Renewable sources in Italy

Until the 1970s the renewable sources of energy they were the ones that produced most of the electricity in Italy, thanks in particular to the hydroelectric plants in the Alps and, secondly, in the Apennines. Today the situation has changed and the renewables contribute much less.

Some data regarding 2012 to get an idea. In that year, Italy produced about 92.2 TWh of electricity from renewable sources, equal to 26.9% of the gross national demand divided as follows: 12.8% from hydroelectric sources, 1.6% from geothermal, 3.9% wind, 5.5% photovoltaic, 3.6% biomass.

To conclude this article on renewable sources of energy with a little positive energy, I remember that in recent years our country has woken up and the production of renewables has grown significantly. We bet on sources of wind and photovoltaics and biomass combustion, before we had focused and limited almost exclusively to renewables such as hydroelectric and geothermal, almost saturating the economically exploitable potential in Italy.

Italian legislative delays remain, but there are new incentives and it is a force game in which it is very much up to us to understand and want a certain direction. Even to us individuals, because with each purchase, ad every gesture, we decide and orient the great national helm, a few degrees, maybe less, but that's no excuse to care.

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Video: Renewable Energy 101. National Geographic (December 2021).