Economy, ecology, technologies and society renewable energies: advantages and disadvantages

De nos jours, plus personne n’ignore l’existence des énergies renouvelables. En effet;elles se sont nettement développées ces dernières années et offrent des avantages impressionnants, notamment économiques puisque, par exemple, en 2021, l’électricité solaire est maintenant moins chère à produire que l’électricité nucléaire ! Ainsi, les énergies dites renouvelables sont de plus en plus privilégiées et préférées partout dans le monde où c’est possible. Quels sont les différents types d’énergies vertes et quels sont leurs avantages et leurs principaux inconvénients ? Cet article essaye de faire le tour des différents types d’énergies renouvelables avec leurs avantages et inconvénients.

Solar energy

As its name indicates, this energy draws its power in the sun or more precisely in the light or infrared radiation.This is by far the most important energy among all renewable energies in terms of power received and available.Indeed, our sun brings the same amount of energy every day to earth and it is colossal: it is estimated that it represents 50,000 times the energy needs of all humanity!The cloudy layer, more or less important, nevertheless prevents the sun from reaching the ground and therefore that this energy can be used.But from a planetary point of view the power radiated by the sun and received by the earth is constant!What will change, depending on the weather and the geographical position is the ability of the earth to receive, absorb and keep this energy.Thus, over a year, the south of France receives more than 2 times more solar energy than the North.This because of the weather but also the more favorable latitude in the South.Here you will find a map of the sunshine of France, this is called the solar irradiation card.

Likewise, it is one of the energies that are most brought to the attention of the media.Indeed, it is this energy which supplies the solar thermal (increasingly rare) and photovoltaic panels which are more and more widespread everywhere today.The solar thermal panels heat water like a boiler and the photovoltaic panels produce electric current.It is for this reason that it is still called photovoltaic electricity.Obtaining this so -called solar electricity requires the physical conversion of the light energy of solar rays into electrical energy.Once this energy is captured, it is transformed by a photovoltaic panel into electrical energy.

The advantages of solar energy

In the energy field, solar energy is privileged and valued because it is one of the simplest to implement and that there is sun, everywhere on earth.Even obviously if certain regions are much sunny than others.You can enjoy solar energy even without a panel: this is called climate or bioclimatic architecture.Thus the solar orientation of a house plays strongly on its contributions in heat, these are free solar contributions and "infinite" ... provided that the sun is there!This helps to reduce your heating bills ... but beware of summer overheating during heat waves.It will be necessary to provide blinds or "stamps" pieces so that your climate house does not become a sauna!

Solar energy is therefore an energy that develops very quickly, it is free, accessible to all and inexhaustible ... but it has a major drawback ...

The drawbacks of solar energy

The main drawback of solar energy is ... the day night cycle of course ... that is to say its daily irregularity.The maximum solar power is reached between noon and 2 p.m. (depending on the lag between the real time and the solar time) and becomes zero at sunset.So do not wait for photovoltaic panels to produce the nightflow of the full moon at night ... The brightness is completely insufficient.

We find this irregularity with the seasons.The higher the latitude, the lower your solar power in the northern hemisphere (in the southern hemisphere it is in summer).This is due to the maximum solar power of the middle of the day which becomes lower and lower with latitude and shorter days.In summer and beyond the Arctic Circle in the North Hemisphere (in the southern hemisphere it is in winter), the phenomenon can nevertheless be reversed due to the midnight sun.Thus at this period solar panels can produce 24 hours a day ... but with a fairly low power due to the inclination of the sun on the horizon.And the polar night obviously cancels all its earnings.

The latest limiting factor in solar energy is the weather: a solar panel will produce less in the rain as you can suspect and under a cloud cover ... even if "it is clear" ... you need direct sunlight so thatA solar thermal panel produces energy ... A photovoltaic solar panel will produce 10 to 15% of its maximum power under a "light" cloud layer ...

Wind energy

Wind energy is wind energy.It is more precisely the recovery of the kinetic energy of the wind.A wind turbine, also called aerogenerator, will indeed convert the kinetic energy of the wind into electrical energy usable for us.Mainly because there are also pumping wind turbines like those that can be seen in westerns ... and windmills, which are mechanical wind turbines.Thus, the strength of the wind allows lafovorizes the setting in motion of certain machines, via blades.Wind turbines exist in different sizes, this goes from a few hundred watts for individuals to several MW.There are currently giant wind turbines of several hundred m high and exceeding 10 unitary MW!General Electric has just presented its 14 MW haliad-X, the most powerful wind turbine in the world and the largest in the world with a nacelle height at 260 m and a maximum height at 367 m!

Wind energy exists in 2 large forms according to their place of installation:

The advantages of wind energy

The main advantage of wind energy from solar energy is that it is not subject to the day night cycle.A wind turbine can work 24 hours a day without any problem!The greater a wind turbine, the better for its energy production.Wind parks develop all over the world and fairly quickly.This means that for 2017, BP declares that worldwide, 4.4% of electric current consumption comes from wind energy.

Sur le même sujet :

Wind energy obviously does not emit greenhouse gases or CO2 during its operation and produces very little waste.The only ecological impact that a wind turbine has during its operation are those linked to maintenance ...

The disadvantage of wind energy

… But a wind turbine emits CO2 and greenhouse gas during saconstruction and its dismantling and its end of life.Indeed, the civil engineering works of a wind turbine are heavy work and a wind turbine has only a lifespan of twenty years.The criticism of wind energy even say that a wind turbine is never profitable on CO2 ... It is undoubtedly false!

A wind turbine is strongly subject to weather and climatic hazards: if a wind turbine can turn very well 7 days a week for a certain period, it can also produce anything during the following 7 days ... Thus the preliminary study is very important.

It must withstand extreme climatic conditions (storm winds) and this especially in the case of off shore wind turbines.Thus a wind turbine can be damaged even destroyed by the too violent wind of a storm even if the engineers do everything to protect it (several various security systems, etc.).Global warming increases violent and extreme phenomena.

A wind turbine also has a significant impact on its environment: birds, noise, visual gene (stroboscopic effect), assembly or maintenance work ... Thus certain wind turbines are even stopped because the impact on nearby inhabitants is too large.

Hydraulic energy

Hydraulic energy is the oldest of energies used by humans.Unlike windmills, we already used hydraulic mill during Antiquity!Paradoxically she does not make people talk about her in the media in recent years ....While it is by far the first renewable energy in terms of energy production!

By definition, "hydraulic" means what is moved by a liquid, in particular water.So it is the energy that derives its source in the flowing water.It is a question of hydroelectric dams, but not only.There are other kinds of energies produced by the hydraulic energy which are for example: the energies of the sea like that of the so -called tide tides, the so -called sea energies, like tidal turbines, and those of the so -called riversriver like river turbines.

The advantages of hydraulic energy

The main advantage of hydraulic energy is its energy and power potential: the 3 gorges dam in China, the most powerful, of the world has a power of 18.2 GW is equivalent to approximately 18 nuclear reactor !!Knowing that there are around fifty nuclear reactor in France and, such a dam could provide more than 30% of French consumption or much more in low consumption period!

The possibility of storage of hydraulic energy is very large advantage compared to wind and solar.In effect;As said above, the intermittent production of production is the main drawback of solar and wind.Hydraulic energy can be stored quite easily on the contrary of these last 2 and we open the valves "when you need it".Thus artificial or natural lakes are even used to store and stamp electrical energy.We are talking about turbinage and pumping or step station.

Another strength of hydraulic energy is that it respects the environment ... If we omit the environmental impact (human, fauna and flora) of the civil engineering of their construction.They do not produce toxic waste.It is estimated that the CO2 emitted by the hydroelectric dams of hydraulic energy per kilowatt hour (KWH) is 25 GCO2/KWH.This calculation is "all understood", that is to say by taking into account the construction, use and maintenance.

In addition, it is the most advanced green electricity energy in France, China, Brazil and in many other countries.

The drawbacks of hydraulic energy

The main drawback of hydraulic energy is its impact on its near human or natural environment.So to build the 3 gorges dam you had to move millions of people and flood hundreds of thousands of km2!

Hydraulic works can also represent a visual gene for some people with their dozens of M high concrete!

They also have an impact on fauna, including the migration of certain species of fish but this is more and more taken into account during the study or after via passages dedicated to fish!

The dams are generally rather reliable but there have been accidents of rupture of the structure which all finished dramatically like the Malpasset dam (Fréjus) or Vajont, subject of the film La Folie des Men

Biomass energy

Biomass is defined as the set of organic matter which can provide energy by combustion, direct or after transformation (such as biofuels or gasification).We designate here by organic matter all the living species present in a given natural environment.The biomass most used by humans is obviously ... firewood!However, with the evolution of science and technology, natural wood is no longer the only popular material ... Pellets or wood pellets, using wood cutting waste has been widely used for many years.Thus, today we have a plurality of materials that can change the field of biomass energy.

The advantages of biomass energy

Although it issues greenhouse gases during its combustion, biomass fully compensates for its discharges during the growth of the plant which absorbs CO2 of air.And as the roots are not generally burning the balance sheet is even negative.The discharges are those which are indirect: production, harvest, transport, transformation ...

It is a local resource that strongly participates in the sustainable development of a country.It is obtained so quickly, because the fuels are quickly found and are above all cheaper.

The drawbacks of biomass energy

The management of the resource for its good real renewability is the main drawback of biomass.A poorly managed forest is not renewable.

The combustion of biomass can also pose pollution problems (soaked and particles for example)

Finally, the storage and transport of biomass are often more complicated than liquid fuels.Here is a complete file on firewood

Geothermal energy

Finally, energy derived from geothermal energy is the last renewable energy that we will evoke quickly here.It is the capture of the heat produced by the ground.This heat can be of solar origin (ground inertia) or due to volcanic activity close to the surface.We therefore distinguish surface geothermal energy and deep geothermal

Surface geothermal energy draws the calories from the ground inertia on the surface, this is the principle of heat pumps with a sensor in the floor of your garden for example.This capture can also be done on surface tablecloths when there is a water table.

The deep geothermal is looking for calories much more deeply (several hundred m) and is only accessible in certain area of the planet, such as certain places in Alsace.Sometimes hot water goes up, like Enisland but these cases are very rare on earth.Deep geothermal energy therefore requires heavy investments and technology is that of oil drilling.Deep geothermal energy therefore remains confidential, especially since it can cause earthquake problems as we have just seen near Strasbourg, Alsace in Alsace.

This energy therefore remains anecdotal and heat pumps, however very fashionable, are only an improvement in electric heating.

According to ESI Business School, renewable energies are of great importance.This is why she works for sustainable development training in her programs.