renewable energies

Renewable energies: advantages and disadvantages

Nowadays, no one is unaware of the existence of renewable energies. Indeed; they have developed significantly in recent years and offer impressive advantages, particularly economic ones since, for example, in 2021, solar electricity is now cheaper to produce than nuclear electricity! Thus, the energy say renewable are increasingly privileged and preferred anywhere in the world where possible. What are the different types green energies and what are their advantages and main disadvantages? This article tries to take a tour of the different types of renewable energy with their advantages and disadvantages.

energy solar

As its name suggests, this energy derives its power from the sun or more precisely in light or infrared radiation. It is, from afar, most important energy among all renewable energies in terms of received and available power. Indeed, our sun brings the same quantity of energy to Earth every day and it is colossal: it is estimated that it represents 50 times the energy needs of all humanity! The cloud layer, more or less important, nevertheless prevents the sun from reaching the ground and therefore that we can use this energy. 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 capacity of the Earth to receive, absorb and conserve this energy. Thus, over a year, the South of France receives more than twice as much solar energy as the North. This is because of the weather but also of the more favorable latitude in the South. Here you will find a sunshine map of France, this is called the solar irradiation map.

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

solar panels

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 because there is sun everywhere on Earth. Even of course if some regions are much sunnier than others. You can enjoy solar energy even without a panel: this is called climatic or bioclimatic architecture. So solar orientation of a house plays strongly on its solar heat gains, they are free and "infinite" solar gains ... provided that the Sun is there! This can really reduce your heating bill… but beware of summer overheating during heat waves. It will be necessary to provide blinds or "buffer" rooms so that your climatic 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 disadvantages of solar energy

The main disadvantage 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 14 p.m. (depending on the difference between real time and solar time) and becomes zero at sunset. So do not wait for photovoltaic panels to produce at night under the glow of the full moon ... the brightness is completely insufficient.

We find this irregularity with the seasons. The higher the latitude, the lower your solar power in winter in the northern hemisphere (in the southern hemisphere it is in summer). This is due to the maximum solar power in the middle of the day which gets lower and lower with latitude and with shorter days. In summer and beyond the Arctic Circle in the northern hemisphere (in the southern hemisphere it is winter), the phenomenon can nevertheless be reversed due to the Soleil de Minuit. 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 gains.

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The last limiting factor of solar energy is the weather : a solar panel will produce less in the rain as you can imagine and under a cloud cover ... even if "it is clear" ... It takes direct solar radiation for a thermal solar panel to produce energy ... a panel solar photovoltaic will produce 10 to 15% of its maximum power under a "light" cloud layer ...

energy wind turbine

Wind energy is the energy of the wind. It is more precisely the recovery of the kinetic energy of the wind. A wind turbine, also called a wind generator, will indeed convert the kinetic energy of the wind into electrical energy that can be used by us. Mainly because there are also pumping wind turbines like the ones you can see in Westerns… and windmills, which are mechanical wind turbines. Thus, the force of the wind allows it favors the setting in motion of certain machines, via blades. Wind turbines come in different sizes, ranging from a few hundred watts for individuals to several MW. There are currently giant wind turbines of several hundred meters high and exceeding 10 MW per unit! General Electric has just presented its 14 MW Haliade-X, the most powerful wind turbine in the world and the largest in the world with a nacelle height of 260 m and a maximum height of 367 m!

With its capacity of 14 MW and a capacity factor of 64%, the Haliade-X is the latest from the American manufacturer, which plans to install it in the United Kingdom and at two other offshore sites in the United States. .

In November 2020, she broke a record of 312 MWh produced in a single daywhich means a single rotation can power a UK household for two days! Or 8,3 seconds of operation for the electricity consumption of a 50 square meter house in France.

These machines, intended to be installed at sea, where the winds are the most powerful, have little to do with the first generations of offshore wind turbines in the 1990s, whose capacities did not exceed a few hundred kilowatts.

Wind energy exists in 2 main forms depending on their location:

  • The onshore wind energy which are the best known since they are easily seen ...
  • The off-shore wind energy which are not located on land, but rather on the sea ... generally a few tens of km from the coast.

coastal wind turbine

The advantages of wind power

The main advantage of wind power over solar power is that it is not subject to the day-night cycle. A wind turbine can operate 24 hours a day no problem ! The larger a wind turbine, the better for its energy production. Wind farms are growing all over the world and quite quickly. As a result, for 2017, BP declares that globally, 4,4% of electricity consumption comes from wind power.

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 related to maintenance ...

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The downside of wind power

... but a wind turbine emits CO2 and greenhouse gases during its construction and its disassembly and end of life. Indeed, the civil engineering works of a wind turbine are heavy work and a wind turbine has only one lifespan of about twenty years. The detractors of wind energy even claim that a wind turbine is never profitable on CO2… it is undoubtedly false!

A wind turbine is heavily subjected to weather and climate hazards : if a wind turbine can run very well 7 days a week for a certain period, it can also produce nothing for the next 7 days… So the preliminary study is very important.

She must resist extreme weather conditions (storm winds) and this especially in the case of offshore wind turbines. So a wind turbine can be damaged or destroyed by too strong wind from a storm even if the engineers do everything to protect it (several various safety systems, etc.). Global warming increases violent and extreme phenomena.

A wind turbine also has a significant impact on its environment : birds, noise, visual disturbance (stroboscopic effect), assembly or maintenance work… Some wind turbines are even shut down because the impact on nearby inhabitants is too great.

Hydraulic energy

L'Hydro-electric power is the oldest of the energies used by man. Unlike windmills, hydraulic mills were already used during Antiquity! Paradoxically, she has not been talked about too much in the media over the past few years .... while it is, by far, the first renewable energy in terms of energy production!

By definition, " hydraulic »Designates what moves by a liquidIncluding the water. It is therefore the energy that derives from the flowing water. It is about hydroelectric dams, but not only them. There are other kinds of energy produced by hydraulic energy which are for example: the energies of the sea like that of the tides say tidal, the energies of the sea say marines, such as turbines and those of the rivers say fluvial like river turbines.
hydraulic dam

The advantages of hydropower

The main advantage of hydropower is its energy and power potential : the 3 gorges dam in China, the most powerful, in the world has a power of 18.2 GW, which is the equivalent of around 18 nuclear reactors !! Knowing that there are about fifty nuclear reactors in France, and such a dam could supply more than 30% of French consumption, or even more in times of low consumption!

The possibility of hydraulic energy storage is very big advantage compared to wind and solar. Indeed; as said above, the intermittence of production is the main drawback of solar and wind power. The hydraulic energy can be stored quite easily, unlike the latter two, and the valves are opened “when needed”. Thus artificial or natural lakes are even used to store and buffer electrical energy. We are talking about turbine and pumping station or WWTP.

Another force hydraulic power 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 of CO2 issued by hydroelectric dams of hydraulic energy by kilowatt hour (KWh) is 25 gCO2 / kWh. This calculation is “all inclusive”, that is to say taking into account the construction, use and maintenance.

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

The disadvantages of hydropower

The main disadvantage of hydropower is its impact on its immediate human or natural environment. So to build the 3 gorges dam it was necessary to move millions of people and flood hundreds of thousands of km2!

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

They also have an impact on wildlife, especially migration of some fish species but this is more and more taken into account during the study or afterwards via passages dedicated to fish!

Dams are generally quite reliable but there have been structural failure accidents which all ended dramatically as the Malpasset dam (Frejus) or Vajont, subject of film The Madness of Men

Biomass energy

biomass is defined as the set of organic materials that can provide energy by combustion, direct or after transformation (such as biofuels or gasification). We denote here by organic matter all living species present in a natural environment given. 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 subject ... pellets or wood pellets, using wood cutting waste have been widely used for many years. Thus, today we have a plurality of subjects that can change the field of biomass energy.

The advantages of biomass energy

Although it emits greenhouse gas during combustion, biomass fully compensates for its releases during plant growth which absorbs CO2 from the air. And since we do not burn the roots, the results are generally negative. The rejections are those which are indirect: production, harvest, transport, transformation ...

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

The disadvantages of biomass energy

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

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

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

The energy of geothermal

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

La surface geothermal energy draws calories from the inertia of the soil at the surface, this is the principle of heat pumps with a sensor in the soil of your garden, for example. This collection can also be done on surface water tables when there is a water table.

La deep geothermal searches for calories much deeper (several hundred m) and is only accessible in certain areas of the planet, such as certain places in Alsace. Sometimes the hot water rises by itself, as in Iceland, but these cases are very rare on Earth. Deep geothermal energy therefore requires heavy investments and the technology is that of oil drilling. Deep geothermal energy therefore remains confidential, especially since it can pose earthquake problems as we have just seen near Strasbourg, in Alsace.

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

geothermal

 

This applies, to only to what kinds of products your potential customers buy, but also to the way these products are promoted through advertising and marketing content. ESI Business School, renewable energies are of great importance. This is why she works for training in Sustainable Development in its programs.

3 comments on “Renewable energies: advantages and disadvantages”

  1. The recycling of elements seems to me not treated, as well as rare materials.
    I talk about it because anti renewable energy often talks about it.

  2. In Auvergne, a village benefits from deep geothermal energy
    In the Cantal department, it's Chaudes-Aigues, south of Saint-Flour.
    The spring provides the city with the warmest water in Europe.

    The thermal establishment which makes the reputation of the city, and benefits from hot water at more than 80 ° at the source! But also the swimming pool
    municipal and the public washhouse, which by the way, is still in operation.

    A real gift from the Earth.

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