Renewable energy is the energy obtained from virtually inexhaustible natural sources, either due to the immense amount of energy they contain, or because they are capable of being regenerated by natural means to moderate the mining extraction of fluids, gases and fossils.[1].
Renewable energies include wind energy, geothermal energy, hydroelectric energy, tidal energy, solar energy, wave energy, biomass "Biomass (energy)") and biofuels. Renewable energy plays a fundamental role in the transition to a sustainable energy system and is essential to mitigate climate change.
From 2011 to 2021, renewable energies increased their share of the global electricity supply from 20% to 28%, while the use of energy from fossil fuels decreased from 68% to 62%, and nuclear energy from 12% to 10%. Hydropower use decreased from 16% to 15%, while solar and wind energy increased from 2% to 10%. Biomass and geothermal energy grew from 2% to 3%.[2][2] In 2022, renewables accounted for 30% of global electricity generation, up from 21% in 1985.[3].
In many countries around the world, renewable energy contributes more than 20% of their total energy supply. Some countries generate more than half of their electricity from renewable energy.[4] A few countries generate all of their electricity from renewable energy.[5] National renewable energy markets are expected to continue growing strongly in the 2020s and beyond.[6].
The deployment of renewable energy is hampered by massive subsidies for fossil fuels.[7] In 2022, the International Energy Agency (IEA) called on all countries to reduce their political, regulatory, permitting and financing obstacles to developing renewable energy.[8] This would increase the chances of the world reaching carbon neutrality by 2050.[8] According to the IEA, to achieve net zero emissions in By 2050, 90% of global electricity generation will need to be produced from renewable sources.[9].
The question of whether nuclear energy is renewable or not remains controversial, but on several occasions, it is said that it is not. There are also debates around geopolitics, the extraction of metals and minerals needed for solar panels and batteries, possible installations in protected areas and the need to recycle solar panels. Although most renewable energy sources are sustainable, some are not. For example, some sources of biomass are unsustainable at the current rate of exploitation.[10].
Renewable energy
Distributed energy strategies
Introduction
Renewable energy is the energy obtained from virtually inexhaustible natural sources, either due to the immense amount of energy they contain, or because they are capable of being regenerated by natural means to moderate the mining extraction of fluids, gases and fossils.[1].
Renewable energies include wind energy, geothermal energy, hydroelectric energy, tidal energy, solar energy, wave energy, biomass "Biomass (energy)") and biofuels. Renewable energy plays a fundamental role in the transition to a sustainable energy system and is essential to mitigate climate change.
From 2011 to 2021, renewable energies increased their share of the global electricity supply from 20% to 28%, while the use of energy from fossil fuels decreased from 68% to 62%, and nuclear energy from 12% to 10%. Hydropower use decreased from 16% to 15%, while solar and wind energy increased from 2% to 10%. Biomass and geothermal energy grew from 2% to 3%.[2][2] In 2022, renewables accounted for 30% of global electricity generation, up from 21% in 1985.[3].
In many countries around the world, renewable energy contributes more than 20% of their total energy supply. Some countries generate more than half of their electricity from renewable energy.[4] A few countries generate all of their electricity from renewable energy.[5] National renewable energy markets are expected to continue growing strongly in the 2020s and beyond.[6].
The deployment of renewable energy is hampered by massive subsidies for fossil fuels.[7] In 2022, the International Energy Agency (IEA) called on all countries to reduce their political, regulatory, permitting and financing obstacles to developing renewable energy.[8] This would increase the chances of the world reaching carbon neutrality by 2050.[8] According to the IEA, to achieve net zero emissions in By 2050, 90% of global electricity generation will need to be produced from renewable sources.[9].
The question of whether nuclear energy is renewable or not remains controversial, but on several occasions, it is said that it is not. There are also debates around geopolitics, the extraction of metals and minerals needed for solar panels and batteries, possible installations in protected areas and the need to recycle solar panels. Although most renewable energy sources are sustainable, some are not. For example, some sources of biomass are unsustainable at the current rate of exploitation.[10].
The energy is obtained through wind turbines that take advantage of the kinetic energy of the wind, transforming it into electrical energy. This resource can be classified as perpetual, and the amount potentially obtainable in a specific geographical area depends on the wind regime and the orography of the place.
A similar, but not identical, concept is that of renewable energies: an alternative energy, or more precisely an alternative energy source is one that can replace conventional energies or energy sources,[11] either because of its lower polluting effect, or fundamentally because of its possibility of renewal.
Energy consumption is one of the great meters of the progress and well-being of a society. However, economic growth and the development of societies are usually accompanied by an increase in energy demand and if energy infrastructure does not grow at the same time as demand, a crisis may occur. Crisis? The current energy situation must be considered as a crisis. Definitely, we cannot continue with this development model that does not fulfill its main role, which is not business profit, but ensuring that inhabitants have access to energy resources to guarantee good living conditions, and obviously, take care of the environment.[9] The concept of energy crisis appears when the energy sources that society supplies are depleted or become drastically more expensive. An economic model like the current one, whose operation depends on continuous growth, also requires an equally growing demand for energy. Since fossil and nuclear energy sources are finite, it is inevitable that at a certain moment the demand cannot be supplied and the entire system collapses, unless other new methods to obtain energy are discovered and developed: these would be alternative energies.
Despite the numerous benefits of renewable energies such as the reduction of greenhouse gas emissions, the increase in consumption of these energies also presents some disadvantages, and also challenges, for example in the case of solar and wind energy they depend on the meteorological and environmental situation that occurs in the places where they are used, therefore their production is not constant, in addition they can also have negative impacts, for example wind energy that can affect wildlife, mainly birds that sometimes collide with the turbines, it can also cause noise pollution. and also visual in nearby areas. The main disadvantage of wind energy is that there is an inability to control the wind, as it is a less predictable energy it cannot be used as the only source of electricity generation. To save the moments when there is not enough wind available for the production of wind energy, a backup of conventional energies and the rest of renewable energies is required[12].
On the other hand, the use of current non-renewable energy sources such as oil, natural gas or coal brings with it problems such as progressive pollution, or the increase in greenhouse gas emissions, as a consequence of obtaining energy from their combustion.
The alternative/conventional energy discussion is not a mere classification of energy sources, but represents a change that will necessarily have to occur during this century.
The concept of "alternative energy" was born around the 1970s, when the possibility that the traditionally used energies, energies of fossil origin, would be exhausted in a more or less short period of time began to be taken into account (an idea especially widespread after the publication, in 1972, of the report to the Club of Rome, The limits of growth) and it was necessary to find more lasting alternatives. Currently, it can no longer be said that they are an alternative possibility: they are a reality and the use of these energies, almost chimerical at the time, extends throughout the world and is part of the normal means of energy generation.
Alternative energy is a synonym for clean energy, green energy or renewable energy. Alternatives are considered all those that come from natural resources and inexhaustible sources, all those that, when produced, do not pollute.[13].
Renewable energy, especially solar and wind, has become cost competitive compared to fossil fuels. According to IRENA (2020), 'the continued reduction in renewable energy costs is transforming energy markets and represents a significant opportunity to reduce global carbon emissions while increasing energy access' (p. 12). This suggests that investment in renewable energy is not only economical, but also key to addressing climate change[14].
Even so, it is important to note that alternative energies, even though they are renewable, are limited and, like any other natural resource, have a maximum exploitation potential, which does not mean that they can be exhausted. Therefore, even if a transition to these new energies can be made smoothly and gradually, they will not allow us to continue with the current economic model based on perpetual growth. This is why the concept of sustainable development has emerged. This model is based on the following premises:
• - The use of renewable energy sources, since the currently exploited fossil sources will end up being exhausted, according to current forecasts, during this century AD. c.
• - The use of clean sources, abandoning conventional combustion processes.
• - The extensive exploitation of energy sources, proposing as an alternative the promotion of self-consumption, which avoids, as far as possible, the construction of large infrastructures for the generation and distribution of electrical energy.
• - The decrease in energy demand, by improving the performance of electrical devices (appliances, lamps, etc.).
• - Reduce or eliminate unnecessary energy consumption. It is not just about consuming more efficiently, but about consuming less, that is, developing an awareness and a culture of energy saving and condemnation of waste.
Classification
Renewable energy sources can be divided into two categories: non-polluting or clean and polluting. Among the first:
• - The arrival of masses of fresh water to masses of salt water: blue energy.
• - Wind: wind energy.
• - The heat of the Earth: geothermal energy.
• - Rivers and freshwater streams: hydraulic or hydroelectric energy.
• - The seas and oceans: tidal energy.
• - The sun: solar energy.
• - Waves: wave energy.
Pollutants are obtained from organic matter or biomass "Biomass (energy)"), and can be used directly as fuel (wood or other solid plant matter), either converted into bioethanol "Ethanol (fuel)") or biogas through organic fermentation processes or into biodiesel, through transesterification reactions and urban waste.
Energy from polluting renewable sources has the same problem as energy produced by fossil fuels: during combustion they emit carbon dioxide, a greenhouse gas, and are often even more polluting, since combustion is not as clean, emitting soot and other solid particles. They fall within renewable energies because as long as the vegetables that produce them can be grown, they will not be exhausted. They are also considered cleaner than their fossil equivalents, because theoretically the carbon dioxide emitted in combustion has been previously absorbed when transformed into organic matter through photosynthesis. In reality, the amount previously absorbed is not equivalent to that emitted in combustion, because in the sowing, harvesting, treatment and transformation processes, energy is also consumed, with its corresponding emissions.
Furthermore, much of the CO emissions can be trapped to feed microalgae cultures/certain bacteria and yeasts (potential source of fertilizers and feed), salt (in the case of brackish or salt water microalgae) and biodiesel/ethanol respectively, and medium for the removal of hydrocarbons and dioxins in the case of bacteria and yeasts (petroleum proteins) and the particulate problem is solved with gasification and complete combustion (combustion at very high temperatures, in a very O-rich atmosphere) in combination with emission decontaminating means such as particle filters and precipitators (such as the Cottrel precipitator), or activated carbon surfaces.
Energy can also be obtained from urban solid waste and sludge from water purification and purification plants. Energy that is also polluting, but would also be polluting to a large extent if it were not used, since the rotting processes of organic matter are carried out with the emission of natural gas and carbon dioxide.
Historical evolution
Renewable energies have constituted an important part of the energy used by humans since ancient times, especially solar, wind and hydraulic energy. Sailing, wind or water mills and the construction arrangements of buildings to take advantage of sunlight are good examples of this.
Without a doubt, the discovery of fire was an event that marked a crucial point in the history of humanity, representing one of the most significant advances for our ancestors. This discovery not only facilitated survival but also helped civilization. Later came other advances such as agricultural and livestock activity, but it was not until the end of the century that the first experiments were carried out to use steam as a source of energy, but almost a hundred years had to pass until James Watt built the first steam engine.[15]
With the invention of the steam engine by James Watt, these forms of use were abandoned, as they were considered unstable over time and capricious, and thermal and electric motors were increasingly used, at a time when the still relatively low consumption did not predict a depletion of sources, nor other environmental problems that later arose.
In the 1970s, renewable energies were considered an alternative to traditional energies, both for their guaranteed present and future availability (unlike fossil fuels that require thousands of years to form) and for their lower environmental impact in the case of clean energies, and for this reason they were called alternative energies. Currently, many of these energies are a reality, not an alternative, so the name alternatives should no longer be used.
The energy sources
Contenido
Las fuentes de energía se pueden dividir en dos grandes subgrupos: permanentes (renovables) y temporales (no renovables).
Non-renewable
Non-renewable energy sources are those that are found in nature in limited quantities. They do not regenerate or do so extremely slowly.[16].
Fossil fuels are non-renewable resources, whose reserves are limited and are depleted with use. At some point they will run out, and it will take millions of years to have them again. The main ones are fossil fuels (oil, natural gas and coal) and, to a certain extent, nuclear energy.
Fossil fuels can be used in solid (coal), liquid (petroleum) or gaseous (natural gas) form. They are accumulations of living beings that lived millions of years ago and that have fossilized, forming coal or hydrocarbons. In the case of coal, these are forests in swampy areas, and in the case of oil and natural gas, they are large masses of marine plankton accumulated on the seabed. In both cases the organic matter was partially decomposed due to lack of oxygen and the action of temperature, pressure and certain bacteria so that molecules with high-energy bonds were stored.
The most used energy in the world is fossil energy. Considering all that is at stake, it is of utmost importance to accurately measure the planet's fossil fuel reserves. A distinction is made between “identified reserves”, even if they are not exploited, and “probable reserves”, which could be discovered with future technologies. According to calculations, the planet can provide energy for 40 more years (if only oil is used) and more than 200 (if coal is continued). There are alternatives currently being studied: nuclear fusion energy – non-renewable, but with immense fuel reserves –, renewable energy or hydrogen cells.
The atomic nucleus of heavy elements such as uranium can be disintegrated (nuclear fission) and release radiant and kinetic energy. Thermonuclear power plants take advantage of this energy to produce electricity through steam turbines.
It is obtained by "breaking" (fissioning) atoms of radioactive minerals in chain reactions that occur inside a nuclear reactor.
A consequence of the production activity of this type of energy is nuclear waste, which can take thousands of years to disappear, because it takes that long to lose radioactivity. Currently, many countries are experimenting with models of "IV generation" fast neutron reactors and Russia has an important model which is the BN-800 in operation with fuel recycled from other reactors (MOX). This allows giving more lives to the fuel used through an industrial process. Another capacity of these reactors is the reduction of waste, given that they have the capacity to transmute transuranic, elements produced with the fission or breakage of the Uranium core and which are highly radioactive or have long half-lives, the Transuranic transmutation converts them into other less radioactive chemical elements or with a short half-life of minutes, days or weeks and then in many cases end up being stable elements or having much lower levels of radioactivity.
There is another possibility of nuclear energy that, so far, is only in the research phase: fusion nuclear energy, which consists of joining (melting) two hydrogen atoms to obtain a helium atom, with abundant energy production. Most experts rule out that this energy source will be available to overcome global warming or for the energy transition. The fuel in this case is hydrogen, abundant on Earth, and the residue is helium, which is neither radioactive nor polluting. If a process is achieved to obtain this energy, it would also be a non-polluting energy.
Currently, some countries prioritize the use of nuclear energy for large production of electrical energy, such as France. Humanity faces major dilemmas regarding the generation, distribution and use of rational energy. In this sense, the socio-controversial problem regarding the use of nuclear energy in the face of the energy crisis in industrialized societies remains open.[17].
Renewable or green
Green energy is a term that describes energy generated from environmentally friendly primary energy sources. Green energies are renewable energies that do not pollute, that is, the method of obtaining or using them does not emit by-products that may have a negative impact on the environment.
Currently, they are gaining greater importance due to the worsening of the greenhouse effect and the consequent global warming, accompanied by greater international awareness regarding this problem. Likewise, national economies that do not have or have exhausted their traditional energy sources (such as oil or gas) and need to acquire these resources from other economies, seek to avoid said energy dependence, as well as the negative impact on their trade balance that this acquisition represents.
The potential energy accumulated in waterfalls can be transformed into electrical energy. Hydroelectric plants take advantage of the energy of rivers to operate turbines that drive electrical generators. In Spain this energy is used to produce around 15% of the total electricity.
One of the most important resources quantitatively in the structure of renewable energies is that from hydroelectric facilities; a clean and indigenous energy source but for which it is necessary to build the necessary infrastructures that allow taking advantage of the available potential with zero fuel costs. The problem with this type of energy is that it depends on weather conditions.
It involves collecting energy from the sun through solar panels and converting it into heat which can be used to satisfy numerous needs. For example, hot water can be obtained for domestic or industrial consumption, or to heat homes, hotels, schools or factories. Also, cooling can be achieved during hot seasons. In agriculture, other types of applications can be achieved, such as solar greenhouses that favor improvements in harvests in quality and quantity, agricultural dryers that consume much less energy if combined with a solar system, and water purification or desalination plants without consuming any type of fuel.
With this type of energy, more than 25% of conventional energy consumption could be reduced in newly built homes, with the consequent reduction in the burning of fossil fuels and environmental deterioration. Obtaining hot water accounts for around 28% of energy consumption in homes and these, in turn, demand just over 12% of the energy in Spain.
Life from solar energy is carried out by the process called plant photosynthesis, which in turn triggers the biological chain. Through photosynthesis, plants that contain chlorophyll transform carbon dioxide and water from mineral products with no energy value into organic materials with high energy content and in turn serve as food for other living beings. Biomass through these processes stores solar energy in the short term in the form of carbon. The energy stored in the photosynthetic process can later be transformed into thermal, electrical energy or fuels of plant origin, releasing the stored carbon dioxide again.
Controversies
There is some controversy about the inclusion of incineration (within biomass energy) and hydraulic energy (on a large scale) as green energies, due to the negative environmental impacts they produce, even though they are renewable energies.
The status of nuclear energy as "clean energy" is the subject of debate. Indeed, although it has one of the lowest rates of greenhouse gas emissions, it generates nuclear waste whose elimination has not yet been resolved. According to the current definition of "waste" it is not clean energy.
Although the advantages of renewable energies are well-known, they have also caused controversy in public opinion. On the one hand, environmental groups such as Greenpeace have raised their voices about the environmental impact that biomass "Biomass (energy)") can cause[28] in the environment and also about the business that many have seen in this new sector. This group along with other environmental associations[29] have rejected the impact that energies such as wind power cause on the environment, although it is less than non-renewable sources. To this end, they have proposed that the generators be installed in the sea, thus obtaining a greater amount of energy and avoiding landscape pollution. Now, these alternatives have been rejected by other sectors, mainly the business sector, due to their high economic cost and also, according to environmentalists, due to the energy companies' desire for a monopoly. Some businessmen, on the other hand, defend the need for such an impact, since in this way the costs are lower and, therefore, the price to be paid by users is lower.
Environmental impact
All energy sources produce some degree of environmental impact. Geothermal energy can be very harmful if heavy metals and greenhouse gases are carried to the surface; Wind power produces a visual impact on the landscape, low-frequency noise, and can be a trap for birds. The least aggressive hydraulic is mini-hydraulics, since large dams cause loss of biodiversity, generate methane from unremoved plant matter, cause pandemics such as yellow fever, dengue, schistosomiasis particularly in temperate climates and hot climates, flood areas with cultural or landscape heritage, generate the movement of entire populations, among others Aswan, Itaipú, Yacyretá and increase the salinity of river beds. Solar energy is among the least aggressive due to the possibility of distributed generation, except for photovoltaic and thermoelectric electricity produced in large grid-connected plants, which generally use a large area of land. Tidal power has been discontinued due to the very high initial costs and the environmental impact it entails. Wave energy together with the energy of ocean currents usually have low environmental impact, since they are usually located on rugged coasts. Biomass energy produces pollution during combustion due to the emission of CO, but it is reabsorbed by the growth of cultivated plants and requires arable land for its development, reducing the amount of arable land available for human consumption and for livestock farming, with the danger of increasing the cost of food and favoring monocultures.
Advantages and disadvantages of renewable energy
ecological energies
Renewable energy sources are different from fossil fuels or nuclear power plants due to their diversity and abundance. It is considered that the Sun will supply these energy sources (solar radiation, wind, rain, etc.) for the next four billion years. The first advantage of a certain number of renewable energy sources is that they do not produce greenhouse gases or other emissions, unlike what happens with fuels, whether fossil or renewable. Some renewable sources do not emit additional carbon dioxide, except those necessary for their construction and operation, and do not present any additional risks, such as nuclear risk. Furthermore, many of these infrastructures are carried out through public-private collaborations, allowing the interests of multiple social actors to be aligned.[30].
However, some renewable energy systems generate particular ecological problems. Thus, the first wind turbines were dangerous for birds, since their blades rotated very quickly, while hydroelectric plants can create obstacles to the emigration of certain fish, a serious problem in many rivers around the world (in those in the northwest of North America that flow into the Pacific Ocean, the salmon population was drastically reduced).
diffuse nature
An inherent problem with renewable energies is their diffuse nature, with the exception of geothermal energy, which, however, is only accessible where the Earth's crust is thin, such as hot springs and geysers.
Since certain renewable energy sources provide energy of relatively low intensity, distributed over large areas, new types of "plants" are necessary to convert them into usable sources. For 1,000 kWh of electricity, annual per capita consumption in Western countries, the owner of a home located in a cloudy area of Europe must install eight square meters of photovoltaic panels (assuming an average energy efficiency of 12.5%).
However, with four square meters of solar thermal collector, a home can obtain a large part of the energy necessary for domestic hot water although, due to the use of simultaneity, apartment buildings can achieve the same performance with a smaller collector surface and, more importantly, with much less investment per home.
Irregularity
The supply of electrical energy requires producing as much electricity as the grid demands. But wind energy and photovoltaics are irregular: they depend on whether the wind blows or the sun shines, and that moment may not coincide with the demand of the grid. They therefore need means of energy storage, such as reversible hydroelectric plants, batteries or fuel cells.[31] Thus, energy storage costs must be taken into account when designing an autonomous renewable energy system independent of the general electrical grid.
On the other hand, although it is true that wind and photovoltaic energy are irregular, this irregularity is highly predictable (with more than 95% reliability).[32] This allows us to know in advance at what times of the next day there may not be enough sun or wind to meet the electrical demand, and to have other supply sources prepared for that moment, such as combined cycle natural gas plants.
Polluting renewable sources
As far as biomass is concerned, it is true that it actively stores the carbon from carbon dioxide, forming its mass with it and grows while releasing oxygen again, when burned it combines carbon with oxygen again, forming carbon dioxide again. Theoretically, the closed cycle would yield zero carbon dioxide emissions, as the emissions resulting from combustion would remain fixed in the new biomass. In practice, polluting energy is used in planting, harvesting and processing, so the balance is negative.
On the other hand, biomass is also not really inexhaustible, even if it is renewable. Its use can only be done in limited cases. There are doubts about the capacity of agriculture to provide the necessary amounts of plant mass if this source becomes popular, which is being demonstrated by the increase in cereal prices due to its use for the production of biofuels. On the other hand, all biofuels produce a greater amount of carbon dioxide per unit of energy produced than their fossil counterparts.
Geothermal energy is not only very geographically restricted but some of its sources are considered polluting. This is because the extraction of high-temperature underground water generates unwanted and toxic salts and minerals being dragged to the surface. The main geothermal plant is located in Tuscany, near the city of Pisa and is called Larderello Geothermal Power Plant") [1] Archived August 21, 2008 at the Wayback Machine. View of kilometers of pipes one meter in diameter that go to the thermal power plant show the landscape impact it generates.
In Argentina, the main power plant was built in the town of Copahue "Copahue (locality)") [3] and electricity generation is currently out of operation. The spring is used for district heating, street and sidewalk heating, and thermal baths.
Geographic diversity
The geographical diversity of resources is also significant. Some countries and regions have significantly better resources than others, particularly in the renewable energy sector. Some countries have significant resources close to major housing centers where electricity demand is significant. The use of such resources on a large scale requires, however, considerable investments in transformation and distribution networks, as well as in production itself.
Administration of electrical networks
If the production of electrical energy from renewable sources became widespread, the distribution and transformation systems would no longer be the large distributors of electrical energy, but they would function to locally balance the electricity needs of small communities. Those who have surplus energy "Energy (technology)") would sell to the deficit sectors, that is, the exploitation of the network should go from a "passive management" where some generators are connected and the system is driven to obtain the "downstream" electricity towards the consumer, to an "active" management, where some generators are distributed in the network, having to constantly monitor the inputs and outputs to guarantee the local balance of the system. That would require major changes in the way networks are managed.
However, small-scale use of renewable energy, which can often be produced "on site", reduces the need for electricity distribution systems. Current systems, rarely economically profitable, revealed that an average home with a solar system with energy storage, and panels of sufficient size, only has to resort to outside sources of electricity for a few hours per week. Therefore, advocates of renewable energy think that electricity distribution systems should be less important and easier to control.
Integration into the landscape
Some critics of renewable energy point to the visual impact of wind generators and large-scale solar installations in rural settings. Alternatives have been proposed to integrate these technologies into the urban and peri-urban landscape, such as the use of solar panels in noise barriers on highways, their installation on building roofs or the incorporation of photovoltaic cells in windows and glass surfaces.[33].
Renewable energy sources today
They represent 18,054%[34] of global electricity consumption, with 90% of hydraulic origin. The rest is very marginal: biomass 5.5%, geothermal 1.5%, wind 0.5% and solar 0.5%.[35].
Around 80% of energy needs in Western industrial societies are centered around industry, heating, air conditioning of buildings and transport (cars, trains, airplanes). However, most large-scale applications of renewable energy focus on electricity production.[36].
In Spain, renewables were responsible for 19.8% of electricity production. In 2007, electricity generation with renewable energy exceeded that of nuclear origin.[37].
In 2011, for the first time, renewable energy production in the United States surpassed nuclear generation, reaching 11.73% of the country's total energy. Of the set of renewable sources, 48% corresponded to biofuels, 35% to hydroelectric plants and the remaining 16% to wind, geothermal and solar energy.[38].
Energy production and self-consumption
Greenpeace presented a report[39] in which it maintains that the use of renewable energy to produce 100% of the energy is technically viable and economically acceptable, which is why, according to the environmental organization, the only thing missing for dirty energy to be put aside in Spain is political will. To achieve this, two parallel developments are necessary: renewable energies and energy efficiency (elimination of superfluous consumption).[40].
On the other hand, 64% of the managers of the main utilities consider that on the horizon of 2018 there will be clean, affordable and renewable technologies of local generation, which will force large corporations in the sector to change their mentality.[41].
The production of green energy is increasing not only due to the development of technology, mainly in the field of solar, but also due to clear political commitments, being also one of the sectors that contributes the most to national economic stability.[42] Thus, the Ministry of Industry, Tourism and Commerce of Spain foresees that green energy will reach 83,330 MW, compared to the current 32,512 MW, and can cover 41% of the electricity demand in 2030.[43][44] To reach this quota, it is planned to previously reach 12% of electricity demand supplied by renewable energies in 2010 and 20% in 2020.[45].
The self-consumption of renewable electricity is contemplated in Royal Decree 1699/2011, of November 18, which regulates the connection to the grid of small power electrical energy production facilities.[46].
By countries
• - Renewable energies in Latin America.
• - Renewable energies in the European Union:
Renewable energies in Germany
Renewable energies in Spain
Renewable energies in Argentina")[47].
Higher education in renewable energy
Engineering
Renewable Energy Engineering at the National Autonomous University of Mexico in Mexico.
Renewable Energy Engineering at the Autonomous University of Baja California in Mexico.
Engineering in Renewable Energy Sources Archived September 16, 2019 at the Wayback Machine. at the Autonomous University of Baja California Sur in Mexico.
Renewable Energy Engineering at Université de Perpignan Via Domitia in France.
Engineering in Sustainable Innovation and Energy at the University of Monterrey in Mexico.
Postgraduate
CEENER at the Autonomous University of Baja California.
Engineering Institute "Mexicali Engineering Institute (UABC)") at the Autonomous University of Baja California.
PROMES in Perpignan, France.
Institutions that promote Renewable Energies
• - IRENA.
• - ISES - International Solar Energy Association.
Continental and national
• - LAWEA") - Latin American Wind Energy Association
ASADES - Argentine Association of Renewable Energy and Environment.
• - EUREC Agency"),[48] European association that connects leading research centers and university departments active in the field of renewable energy technology.
IDAE, Institute for Energy Diversification and Saving, Spain.
• - Annex:List of countries by the production of electricity from renewable sources.
• - Fuel crisis.
• - Eco-efficiency.
• - Alternative energy.
• - Energy of the future.
• - Production of electricity from sunlight.
• - Scout Moor wind farm.
• - Wikimedia Commons hosts a multimedia category on Renewable Energy.
[2] ↑ a b Secretariat, REN21 (14 de junio de 2019). «REN21 Renewables Global Status Report». REN21 (en inglés estadounidense). Consultado el 13 de junio de 2024.: https://www.ren21.net/reports/global-status-report/
[4] ↑ Ritchie, Hannah; Roser, Max; Rosado, Pablo (11 de marzo de 2024). «Renewable Energy». Our World in Data. Consultado el 13 de junio de 2024.: https://ourworldindata.org/renewable-energy
[7] ↑ Timperley, Jocelyn (20 de octubre de 2021). «Why fossil fuel subsidies are so hard to kill». Nature (en inglés) 598 (7881): 403-405. ISSN 0028-0836. doi:10.1038/d41586-021-02847-2. Consultado el 13 de junio de 2024.: https://www.nature.com/articles/d41586-021-02847-2
[12] ↑ Moreno Diaz, Angelo Hector. Estudio de prefactibilidad para la instalación de una planta de energía eólica en Paracas. Universidad de Lima. Consultado el 12 de octubre de 2024.: https://dx.doi.org/10.26439/ulima.tesis/4270
[13] ↑ https://www.factorenergia.com/wp-content/uploads/2016/06/emiliresp.jpg, Emili Rousaud Socio fundador de Factorenergia. «Energías alternativas: Qué son y qué tipos existen». factorenergia. Consultado el 10 de septiembre de 2020.: https://www.factorenergia.com/wp-content/uploads/2016/06/emiliresp.jpg
[22] ↑ Era muy importante con los primeros generadores, cuyas palas giraban con velocidades mucho mayores, parecida a las hélices de los aviones, por lo que no permitían que las aves las vieran.
[30] ↑ Fleta- Asín, J; Muñoz, F. (17 de enero de 2021). «Renewable energy public–private partnerships in developing countries: Determinants of private investment». Sustainable Development. doi:10.1002/sd.2165. Consultado el 02/02/2024.: https://onlinelibrary.wiley.com/doi/abs/10.1002/sd.2165
[36] ↑ «“APLICACIÓN DE LA ENERGÍA RENOVABLE: PANELES SOLARES.”». MONOGRAFIA PARA OPTAR AL TÍTULO DE MASTER EN DIDACTICA DE LA FÍSICA. Consultado el 10 de septiembre de 2020.: http://riul.unanleon.edu.ni:8080/jspui/retrieve/738
[39] ↑ García Ortega, Jose Luis et al. (2006) Renovables 100 %. Un sistema eléctrico renovable para la España peninsular viabilidad económica Archivado el 3 de enero de 2008 en Wayback Machine. Greenpeace.: http://www.greenpeace.org/espana/reports/informes-renovables-100.
The energy is obtained through wind turbines that take advantage of the kinetic energy of the wind, transforming it into electrical energy. This resource can be classified as perpetual, and the amount potentially obtainable in a specific geographical area depends on the wind regime and the orography of the place.
A similar, but not identical, concept is that of renewable energies: an alternative energy, or more precisely an alternative energy source is one that can replace conventional energies or energy sources,[11] either because of its lower polluting effect, or fundamentally because of its possibility of renewal.
Energy consumption is one of the great meters of the progress and well-being of a society. However, economic growth and the development of societies are usually accompanied by an increase in energy demand and if energy infrastructure does not grow at the same time as demand, a crisis may occur. Crisis? The current energy situation must be considered as a crisis. Definitely, we cannot continue with this development model that does not fulfill its main role, which is not business profit, but ensuring that inhabitants have access to energy resources to guarantee good living conditions, and obviously, take care of the environment.[9] The concept of energy crisis appears when the energy sources that society supplies are depleted or become drastically more expensive. An economic model like the current one, whose operation depends on continuous growth, also requires an equally growing demand for energy. Since fossil and nuclear energy sources are finite, it is inevitable that at a certain moment the demand cannot be supplied and the entire system collapses, unless other new methods to obtain energy are discovered and developed: these would be alternative energies.
Despite the numerous benefits of renewable energies such as the reduction of greenhouse gas emissions, the increase in consumption of these energies also presents some disadvantages, and also challenges, for example in the case of solar and wind energy they depend on the meteorological and environmental situation that occurs in the places where they are used, therefore their production is not constant, in addition they can also have negative impacts, for example wind energy that can affect wildlife, mainly birds that sometimes collide with the turbines, it can also cause noise pollution. and also visual in nearby areas. The main disadvantage of wind energy is that there is an inability to control the wind, as it is a less predictable energy it cannot be used as the only source of electricity generation. To save the moments when there is not enough wind available for the production of wind energy, a backup of conventional energies and the rest of renewable energies is required[12].
On the other hand, the use of current non-renewable energy sources such as oil, natural gas or coal brings with it problems such as progressive pollution, or the increase in greenhouse gas emissions, as a consequence of obtaining energy from their combustion.
The alternative/conventional energy discussion is not a mere classification of energy sources, but represents a change that will necessarily have to occur during this century.
The concept of "alternative energy" was born around the 1970s, when the possibility that the traditionally used energies, energies of fossil origin, would be exhausted in a more or less short period of time began to be taken into account (an idea especially widespread after the publication, in 1972, of the report to the Club of Rome, The limits of growth) and it was necessary to find more lasting alternatives. Currently, it can no longer be said that they are an alternative possibility: they are a reality and the use of these energies, almost chimerical at the time, extends throughout the world and is part of the normal means of energy generation.
Alternative energy is a synonym for clean energy, green energy or renewable energy. Alternatives are considered all those that come from natural resources and inexhaustible sources, all those that, when produced, do not pollute.[13].
Renewable energy, especially solar and wind, has become cost competitive compared to fossil fuels. According to IRENA (2020), 'the continued reduction in renewable energy costs is transforming energy markets and represents a significant opportunity to reduce global carbon emissions while increasing energy access' (p. 12). This suggests that investment in renewable energy is not only economical, but also key to addressing climate change[14].
Even so, it is important to note that alternative energies, even though they are renewable, are limited and, like any other natural resource, have a maximum exploitation potential, which does not mean that they can be exhausted. Therefore, even if a transition to these new energies can be made smoothly and gradually, they will not allow us to continue with the current economic model based on perpetual growth. This is why the concept of sustainable development has emerged. This model is based on the following premises:
• - The use of renewable energy sources, since the currently exploited fossil sources will end up being exhausted, according to current forecasts, during this century AD. c.
• - The use of clean sources, abandoning conventional combustion processes.
• - The extensive exploitation of energy sources, proposing as an alternative the promotion of self-consumption, which avoids, as far as possible, the construction of large infrastructures for the generation and distribution of electrical energy.
• - The decrease in energy demand, by improving the performance of electrical devices (appliances, lamps, etc.).
• - Reduce or eliminate unnecessary energy consumption. It is not just about consuming more efficiently, but about consuming less, that is, developing an awareness and a culture of energy saving and condemnation of waste.
Classification
Renewable energy sources can be divided into two categories: non-polluting or clean and polluting. Among the first:
• - The arrival of masses of fresh water to masses of salt water: blue energy.
• - Wind: wind energy.
• - The heat of the Earth: geothermal energy.
• - Rivers and freshwater streams: hydraulic or hydroelectric energy.
• - The seas and oceans: tidal energy.
• - The sun: solar energy.
• - Waves: wave energy.
Pollutants are obtained from organic matter or biomass "Biomass (energy)"), and can be used directly as fuel (wood or other solid plant matter), either converted into bioethanol "Ethanol (fuel)") or biogas through organic fermentation processes or into biodiesel, through transesterification reactions and urban waste.
Energy from polluting renewable sources has the same problem as energy produced by fossil fuels: during combustion they emit carbon dioxide, a greenhouse gas, and are often even more polluting, since combustion is not as clean, emitting soot and other solid particles. They fall within renewable energies because as long as the vegetables that produce them can be grown, they will not be exhausted. They are also considered cleaner than their fossil equivalents, because theoretically the carbon dioxide emitted in combustion has been previously absorbed when transformed into organic matter through photosynthesis. In reality, the amount previously absorbed is not equivalent to that emitted in combustion, because in the sowing, harvesting, treatment and transformation processes, energy is also consumed, with its corresponding emissions.
Furthermore, much of the CO emissions can be trapped to feed microalgae cultures/certain bacteria and yeasts (potential source of fertilizers and feed), salt (in the case of brackish or salt water microalgae) and biodiesel/ethanol respectively, and medium for the removal of hydrocarbons and dioxins in the case of bacteria and yeasts (petroleum proteins) and the particulate problem is solved with gasification and complete combustion (combustion at very high temperatures, in a very O-rich atmosphere) in combination with emission decontaminating means such as particle filters and precipitators (such as the Cottrel precipitator), or activated carbon surfaces.
Energy can also be obtained from urban solid waste and sludge from water purification and purification plants. Energy that is also polluting, but would also be polluting to a large extent if it were not used, since the rotting processes of organic matter are carried out with the emission of natural gas and carbon dioxide.
Historical evolution
Renewable energies have constituted an important part of the energy used by humans since ancient times, especially solar, wind and hydraulic energy. Sailing, wind or water mills and the construction arrangements of buildings to take advantage of sunlight are good examples of this.
Without a doubt, the discovery of fire was an event that marked a crucial point in the history of humanity, representing one of the most significant advances for our ancestors. This discovery not only facilitated survival but also helped civilization. Later came other advances such as agricultural and livestock activity, but it was not until the end of the century that the first experiments were carried out to use steam as a source of energy, but almost a hundred years had to pass until James Watt built the first steam engine.[15]
With the invention of the steam engine by James Watt, these forms of use were abandoned, as they were considered unstable over time and capricious, and thermal and electric motors were increasingly used, at a time when the still relatively low consumption did not predict a depletion of sources, nor other environmental problems that later arose.
In the 1970s, renewable energies were considered an alternative to traditional energies, both for their guaranteed present and future availability (unlike fossil fuels that require thousands of years to form) and for their lower environmental impact in the case of clean energies, and for this reason they were called alternative energies. Currently, many of these energies are a reality, not an alternative, so the name alternatives should no longer be used.
The energy sources
Contenido
Las fuentes de energía se pueden dividir en dos grandes subgrupos: permanentes (renovables) y temporales (no renovables).
Non-renewable
Non-renewable energy sources are those that are found in nature in limited quantities. They do not regenerate or do so extremely slowly.[16].
Fossil fuels are non-renewable resources, whose reserves are limited and are depleted with use. At some point they will run out, and it will take millions of years to have them again. The main ones are fossil fuels (oil, natural gas and coal) and, to a certain extent, nuclear energy.
Fossil fuels can be used in solid (coal), liquid (petroleum) or gaseous (natural gas) form. They are accumulations of living beings that lived millions of years ago and that have fossilized, forming coal or hydrocarbons. In the case of coal, these are forests in swampy areas, and in the case of oil and natural gas, they are large masses of marine plankton accumulated on the seabed. In both cases the organic matter was partially decomposed due to lack of oxygen and the action of temperature, pressure and certain bacteria so that molecules with high-energy bonds were stored.
The most used energy in the world is fossil energy. Considering all that is at stake, it is of utmost importance to accurately measure the planet's fossil fuel reserves. A distinction is made between “identified reserves”, even if they are not exploited, and “probable reserves”, which could be discovered with future technologies. According to calculations, the planet can provide energy for 40 more years (if only oil is used) and more than 200 (if coal is continued). There are alternatives currently being studied: nuclear fusion energy – non-renewable, but with immense fuel reserves –, renewable energy or hydrogen cells.
The atomic nucleus of heavy elements such as uranium can be disintegrated (nuclear fission) and release radiant and kinetic energy. Thermonuclear power plants take advantage of this energy to produce electricity through steam turbines.
It is obtained by "breaking" (fissioning) atoms of radioactive minerals in chain reactions that occur inside a nuclear reactor.
A consequence of the production activity of this type of energy is nuclear waste, which can take thousands of years to disappear, because it takes that long to lose radioactivity. Currently, many countries are experimenting with models of "IV generation" fast neutron reactors and Russia has an important model which is the BN-800 in operation with fuel recycled from other reactors (MOX). This allows giving more lives to the fuel used through an industrial process. Another capacity of these reactors is the reduction of waste, given that they have the capacity to transmute transuranic, elements produced with the fission or breakage of the Uranium core and which are highly radioactive or have long half-lives, the Transuranic transmutation converts them into other less radioactive chemical elements or with a short half-life of minutes, days or weeks and then in many cases end up being stable elements or having much lower levels of radioactivity.
There is another possibility of nuclear energy that, so far, is only in the research phase: fusion nuclear energy, which consists of joining (melting) two hydrogen atoms to obtain a helium atom, with abundant energy production. Most experts rule out that this energy source will be available to overcome global warming or for the energy transition. The fuel in this case is hydrogen, abundant on Earth, and the residue is helium, which is neither radioactive nor polluting. If a process is achieved to obtain this energy, it would also be a non-polluting energy.
Currently, some countries prioritize the use of nuclear energy for large production of electrical energy, such as France. Humanity faces major dilemmas regarding the generation, distribution and use of rational energy. In this sense, the socio-controversial problem regarding the use of nuclear energy in the face of the energy crisis in industrialized societies remains open.[17].
Renewable or green
Green energy is a term that describes energy generated from environmentally friendly primary energy sources. Green energies are renewable energies that do not pollute, that is, the method of obtaining or using them does not emit by-products that may have a negative impact on the environment.
Currently, they are gaining greater importance due to the worsening of the greenhouse effect and the consequent global warming, accompanied by greater international awareness regarding this problem. Likewise, national economies that do not have or have exhausted their traditional energy sources (such as oil or gas) and need to acquire these resources from other economies, seek to avoid said energy dependence, as well as the negative impact on their trade balance that this acquisition represents.
The potential energy accumulated in waterfalls can be transformed into electrical energy. Hydroelectric plants take advantage of the energy of rivers to operate turbines that drive electrical generators. In Spain this energy is used to produce around 15% of the total electricity.
One of the most important resources quantitatively in the structure of renewable energies is that from hydroelectric facilities; a clean and indigenous energy source but for which it is necessary to build the necessary infrastructures that allow taking advantage of the available potential with zero fuel costs. The problem with this type of energy is that it depends on weather conditions.
It involves collecting energy from the sun through solar panels and converting it into heat which can be used to satisfy numerous needs. For example, hot water can be obtained for domestic or industrial consumption, or to heat homes, hotels, schools or factories. Also, cooling can be achieved during hot seasons. In agriculture, other types of applications can be achieved, such as solar greenhouses that favor improvements in harvests in quality and quantity, agricultural dryers that consume much less energy if combined with a solar system, and water purification or desalination plants without consuming any type of fuel.
With this type of energy, more than 25% of conventional energy consumption could be reduced in newly built homes, with the consequent reduction in the burning of fossil fuels and environmental deterioration. Obtaining hot water accounts for around 28% of energy consumption in homes and these, in turn, demand just over 12% of the energy in Spain.
Life from solar energy is carried out by the process called plant photosynthesis, which in turn triggers the biological chain. Through photosynthesis, plants that contain chlorophyll transform carbon dioxide and water from mineral products with no energy value into organic materials with high energy content and in turn serve as food for other living beings. Biomass through these processes stores solar energy in the short term in the form of carbon. The energy stored in the photosynthetic process can later be transformed into thermal, electrical energy or fuels of plant origin, releasing the stored carbon dioxide again.
Controversies
There is some controversy about the inclusion of incineration (within biomass energy) and hydraulic energy (on a large scale) as green energies, due to the negative environmental impacts they produce, even though they are renewable energies.
The status of nuclear energy as "clean energy" is the subject of debate. Indeed, although it has one of the lowest rates of greenhouse gas emissions, it generates nuclear waste whose elimination has not yet been resolved. According to the current definition of "waste" it is not clean energy.
Although the advantages of renewable energies are well-known, they have also caused controversy in public opinion. On the one hand, environmental groups such as Greenpeace have raised their voices about the environmental impact that biomass "Biomass (energy)") can cause[28] in the environment and also about the business that many have seen in this new sector. This group along with other environmental associations[29] have rejected the impact that energies such as wind power cause on the environment, although it is less than non-renewable sources. To this end, they have proposed that the generators be installed in the sea, thus obtaining a greater amount of energy and avoiding landscape pollution. Now, these alternatives have been rejected by other sectors, mainly the business sector, due to their high economic cost and also, according to environmentalists, due to the energy companies' desire for a monopoly. Some businessmen, on the other hand, defend the need for such an impact, since in this way the costs are lower and, therefore, the price to be paid by users is lower.
Environmental impact
All energy sources produce some degree of environmental impact. Geothermal energy can be very harmful if heavy metals and greenhouse gases are carried to the surface; Wind power produces a visual impact on the landscape, low-frequency noise, and can be a trap for birds. The least aggressive hydraulic is mini-hydraulics, since large dams cause loss of biodiversity, generate methane from unremoved plant matter, cause pandemics such as yellow fever, dengue, schistosomiasis particularly in temperate climates and hot climates, flood areas with cultural or landscape heritage, generate the movement of entire populations, among others Aswan, Itaipú, Yacyretá and increase the salinity of river beds. Solar energy is among the least aggressive due to the possibility of distributed generation, except for photovoltaic and thermoelectric electricity produced in large grid-connected plants, which generally use a large area of land. Tidal power has been discontinued due to the very high initial costs and the environmental impact it entails. Wave energy together with the energy of ocean currents usually have low environmental impact, since they are usually located on rugged coasts. Biomass energy produces pollution during combustion due to the emission of CO, but it is reabsorbed by the growth of cultivated plants and requires arable land for its development, reducing the amount of arable land available for human consumption and for livestock farming, with the danger of increasing the cost of food and favoring monocultures.
Advantages and disadvantages of renewable energy
ecological energies
Renewable energy sources are different from fossil fuels or nuclear power plants due to their diversity and abundance. It is considered that the Sun will supply these energy sources (solar radiation, wind, rain, etc.) for the next four billion years. The first advantage of a certain number of renewable energy sources is that they do not produce greenhouse gases or other emissions, unlike what happens with fuels, whether fossil or renewable. Some renewable sources do not emit additional carbon dioxide, except those necessary for their construction and operation, and do not present any additional risks, such as nuclear risk. Furthermore, many of these infrastructures are carried out through public-private collaborations, allowing the interests of multiple social actors to be aligned.[30].
However, some renewable energy systems generate particular ecological problems. Thus, the first wind turbines were dangerous for birds, since their blades rotated very quickly, while hydroelectric plants can create obstacles to the emigration of certain fish, a serious problem in many rivers around the world (in those in the northwest of North America that flow into the Pacific Ocean, the salmon population was drastically reduced).
diffuse nature
An inherent problem with renewable energies is their diffuse nature, with the exception of geothermal energy, which, however, is only accessible where the Earth's crust is thin, such as hot springs and geysers.
Since certain renewable energy sources provide energy of relatively low intensity, distributed over large areas, new types of "plants" are necessary to convert them into usable sources. For 1,000 kWh of electricity, annual per capita consumption in Western countries, the owner of a home located in a cloudy area of Europe must install eight square meters of photovoltaic panels (assuming an average energy efficiency of 12.5%).
However, with four square meters of solar thermal collector, a home can obtain a large part of the energy necessary for domestic hot water although, due to the use of simultaneity, apartment buildings can achieve the same performance with a smaller collector surface and, more importantly, with much less investment per home.
Irregularity
The supply of electrical energy requires producing as much electricity as the grid demands. But wind energy and photovoltaics are irregular: they depend on whether the wind blows or the sun shines, and that moment may not coincide with the demand of the grid. They therefore need means of energy storage, such as reversible hydroelectric plants, batteries or fuel cells.[31] Thus, energy storage costs must be taken into account when designing an autonomous renewable energy system independent of the general electrical grid.
On the other hand, although it is true that wind and photovoltaic energy are irregular, this irregularity is highly predictable (with more than 95% reliability).[32] This allows us to know in advance at what times of the next day there may not be enough sun or wind to meet the electrical demand, and to have other supply sources prepared for that moment, such as combined cycle natural gas plants.
Polluting renewable sources
As far as biomass is concerned, it is true that it actively stores the carbon from carbon dioxide, forming its mass with it and grows while releasing oxygen again, when burned it combines carbon with oxygen again, forming carbon dioxide again. Theoretically, the closed cycle would yield zero carbon dioxide emissions, as the emissions resulting from combustion would remain fixed in the new biomass. In practice, polluting energy is used in planting, harvesting and processing, so the balance is negative.
On the other hand, biomass is also not really inexhaustible, even if it is renewable. Its use can only be done in limited cases. There are doubts about the capacity of agriculture to provide the necessary amounts of plant mass if this source becomes popular, which is being demonstrated by the increase in cereal prices due to its use for the production of biofuels. On the other hand, all biofuels produce a greater amount of carbon dioxide per unit of energy produced than their fossil counterparts.
Geothermal energy is not only very geographically restricted but some of its sources are considered polluting. This is because the extraction of high-temperature underground water generates unwanted and toxic salts and minerals being dragged to the surface. The main geothermal plant is located in Tuscany, near the city of Pisa and is called Larderello Geothermal Power Plant") [1] Archived August 21, 2008 at the Wayback Machine. View of kilometers of pipes one meter in diameter that go to the thermal power plant show the landscape impact it generates.
In Argentina, the main power plant was built in the town of Copahue "Copahue (locality)") [3] and electricity generation is currently out of operation. The spring is used for district heating, street and sidewalk heating, and thermal baths.
Geographic diversity
The geographical diversity of resources is also significant. Some countries and regions have significantly better resources than others, particularly in the renewable energy sector. Some countries have significant resources close to major housing centers where electricity demand is significant. The use of such resources on a large scale requires, however, considerable investments in transformation and distribution networks, as well as in production itself.
Administration of electrical networks
If the production of electrical energy from renewable sources became widespread, the distribution and transformation systems would no longer be the large distributors of electrical energy, but they would function to locally balance the electricity needs of small communities. Those who have surplus energy "Energy (technology)") would sell to the deficit sectors, that is, the exploitation of the network should go from a "passive management" where some generators are connected and the system is driven to obtain the "downstream" electricity towards the consumer, to an "active" management, where some generators are distributed in the network, having to constantly monitor the inputs and outputs to guarantee the local balance of the system. That would require major changes in the way networks are managed.
However, small-scale use of renewable energy, which can often be produced "on site", reduces the need for electricity distribution systems. Current systems, rarely economically profitable, revealed that an average home with a solar system with energy storage, and panels of sufficient size, only has to resort to outside sources of electricity for a few hours per week. Therefore, advocates of renewable energy think that electricity distribution systems should be less important and easier to control.
Integration into the landscape
Some critics of renewable energy point to the visual impact of wind generators and large-scale solar installations in rural settings. Alternatives have been proposed to integrate these technologies into the urban and peri-urban landscape, such as the use of solar panels in noise barriers on highways, their installation on building roofs or the incorporation of photovoltaic cells in windows and glass surfaces.[33].
Renewable energy sources today
They represent 18,054%[34] of global electricity consumption, with 90% of hydraulic origin. The rest is very marginal: biomass 5.5%, geothermal 1.5%, wind 0.5% and solar 0.5%.[35].
Around 80% of energy needs in Western industrial societies are centered around industry, heating, air conditioning of buildings and transport (cars, trains, airplanes). However, most large-scale applications of renewable energy focus on electricity production.[36].
In Spain, renewables were responsible for 19.8% of electricity production. In 2007, electricity generation with renewable energy exceeded that of nuclear origin.[37].
In 2011, for the first time, renewable energy production in the United States surpassed nuclear generation, reaching 11.73% of the country's total energy. Of the set of renewable sources, 48% corresponded to biofuels, 35% to hydroelectric plants and the remaining 16% to wind, geothermal and solar energy.[38].
Energy production and self-consumption
Greenpeace presented a report[39] in which it maintains that the use of renewable energy to produce 100% of the energy is technically viable and economically acceptable, which is why, according to the environmental organization, the only thing missing for dirty energy to be put aside in Spain is political will. To achieve this, two parallel developments are necessary: renewable energies and energy efficiency (elimination of superfluous consumption).[40].
On the other hand, 64% of the managers of the main utilities consider that on the horizon of 2018 there will be clean, affordable and renewable technologies of local generation, which will force large corporations in the sector to change their mentality.[41].
The production of green energy is increasing not only due to the development of technology, mainly in the field of solar, but also due to clear political commitments, being also one of the sectors that contributes the most to national economic stability.[42] Thus, the Ministry of Industry, Tourism and Commerce of Spain foresees that green energy will reach 83,330 MW, compared to the current 32,512 MW, and can cover 41% of the electricity demand in 2030.[43][44] To reach this quota, it is planned to previously reach 12% of electricity demand supplied by renewable energies in 2010 and 20% in 2020.[45].
The self-consumption of renewable electricity is contemplated in Royal Decree 1699/2011, of November 18, which regulates the connection to the grid of small power electrical energy production facilities.[46].
By countries
• - Renewable energies in Latin America.
• - Renewable energies in the European Union:
Renewable energies in Germany
Renewable energies in Spain
Renewable energies in Argentina")[47].
Higher education in renewable energy
Engineering
Renewable Energy Engineering at the National Autonomous University of Mexico in Mexico.
Renewable Energy Engineering at the Autonomous University of Baja California in Mexico.
Engineering in Renewable Energy Sources Archived September 16, 2019 at the Wayback Machine. at the Autonomous University of Baja California Sur in Mexico.
Renewable Energy Engineering at Université de Perpignan Via Domitia in France.
Engineering in Sustainable Innovation and Energy at the University of Monterrey in Mexico.
Postgraduate
CEENER at the Autonomous University of Baja California.
Engineering Institute "Mexicali Engineering Institute (UABC)") at the Autonomous University of Baja California.
PROMES in Perpignan, France.
Institutions that promote Renewable Energies
• - IRENA.
• - ISES - International Solar Energy Association.
Continental and national
• - LAWEA") - Latin American Wind Energy Association
ASADES - Argentine Association of Renewable Energy and Environment.
• - EUREC Agency"),[48] European association that connects leading research centers and university departments active in the field of renewable energy technology.
IDAE, Institute for Energy Diversification and Saving, Spain.
• - Annex:List of countries by the production of electricity from renewable sources.
• - Fuel crisis.
• - Eco-efficiency.
• - Alternative energy.
• - Energy of the future.
• - Production of electricity from sunlight.
• - Scout Moor wind farm.
• - Wikimedia Commons hosts a multimedia category on Renewable Energy.
[2] ↑ a b Secretariat, REN21 (14 de junio de 2019). «REN21 Renewables Global Status Report». REN21 (en inglés estadounidense). Consultado el 13 de junio de 2024.: https://www.ren21.net/reports/global-status-report/
[4] ↑ Ritchie, Hannah; Roser, Max; Rosado, Pablo (11 de marzo de 2024). «Renewable Energy». Our World in Data. Consultado el 13 de junio de 2024.: https://ourworldindata.org/renewable-energy
[7] ↑ Timperley, Jocelyn (20 de octubre de 2021). «Why fossil fuel subsidies are so hard to kill». Nature (en inglés) 598 (7881): 403-405. ISSN 0028-0836. doi:10.1038/d41586-021-02847-2. Consultado el 13 de junio de 2024.: https://www.nature.com/articles/d41586-021-02847-2
[12] ↑ Moreno Diaz, Angelo Hector. Estudio de prefactibilidad para la instalación de una planta de energía eólica en Paracas. Universidad de Lima. Consultado el 12 de octubre de 2024.: https://dx.doi.org/10.26439/ulima.tesis/4270
[13] ↑ https://www.factorenergia.com/wp-content/uploads/2016/06/emiliresp.jpg, Emili Rousaud Socio fundador de Factorenergia. «Energías alternativas: Qué son y qué tipos existen». factorenergia. Consultado el 10 de septiembre de 2020.: https://www.factorenergia.com/wp-content/uploads/2016/06/emiliresp.jpg
[22] ↑ Era muy importante con los primeros generadores, cuyas palas giraban con velocidades mucho mayores, parecida a las hélices de los aviones, por lo que no permitían que las aves las vieran.
[30] ↑ Fleta- Asín, J; Muñoz, F. (17 de enero de 2021). «Renewable energy public–private partnerships in developing countries: Determinants of private investment». Sustainable Development. doi:10.1002/sd.2165. Consultado el 02/02/2024.: https://onlinelibrary.wiley.com/doi/abs/10.1002/sd.2165
[36] ↑ «“APLICACIÓN DE LA ENERGÍA RENOVABLE: PANELES SOLARES.”». MONOGRAFIA PARA OPTAR AL TÍTULO DE MASTER EN DIDACTICA DE LA FÍSICA. Consultado el 10 de septiembre de 2020.: http://riul.unanleon.edu.ni:8080/jspui/retrieve/738
[39] ↑ García Ortega, Jose Luis et al. (2006) Renovables 100 %. Un sistema eléctrico renovable para la España peninsular viabilidad económica Archivado el 3 de enero de 2008 en Wayback Machine. Greenpeace.: http://www.greenpeace.org/espana/reports/informes-renovables-100.
Solar energy is a source of life and the origin of most other forms of energy on Earth.[18] Every year solar radiation contributes energy to the Earth equivalent to several thousand times the amount of energy consumed by humanity. By properly collecting solar radiation, it can be transformed into other forms of energy such as thermal energy or electrical energy using solar panels.
Using solar collectors, solar energy can be transformed into thermal energy, and using photovoltaic panels, light energy can be transformed into electrical energy. Both processes have nothing to do with each other in terms of their technology. Likewise, in solar thermal power plants, the thermal energy from solar collectors is used to generate electricity.
There are two components in solar radiation: direct radiation and diffuse radiation. Direct radiation is that which arrives directly from the solar focus, without reflections "Reflection (physics)") or intermediate refractions. The diffuse is that emitted by the daytime sky thanks to the multiple phenomena of solar reflection and refraction in the atmosphere, in the clouds, and the rest of the atmospheric and terrestrial elements. Direct radiation can be reflected and concentrated for use, while diffuse radiation coming from all directions cannot be concentrated. However, both direct radiation and diffuse radiation are usable.
A distinction can be made between active and passive receivers in that the former use mechanisms to orient the receiving system toward the Sun—called trackers—and better capture direct radiation.
An important advantage of solar energy is that it allows the generation of energy at the same place of consumption through architectural integration in buildings. Thus, we can give rise to distributed generation systems in which transport-related losses – which currently account for approximately 40% of the total – and energy dependency are almost completely eliminated.
The different photovoltaic technologies are adapted to get the maximum possible performance from the energy we receive from the sun. In this way, for example, concentrated solar photovoltaic (CPV) systems use direct radiation with active receivers to maximize energy production and thus achieve a lower cost per kWh produced. This technology is very efficient for places with high solar radiation, but currently it cannot compete in price in locations with low solar radiation such as Central Europe, where technologies such as the thin film solar cell (also called Thin Film) are also managing to reduce the price of traditional photovoltaic technology to levels never seen before.
Wind energy is the energy obtained from the force of the wind, that is, by using the kinetic energy generated by air currents.[19] It is obtained through wind turbines that convert the kinetic energy of the wind into electrical energy by means of blades or propellers "Propeller (device)") that rotate a central shaft connected, through a series of gears (the transmission) to an electric generator.
The term aeolian comes from the Latin Aeolicus (ancient Greek Αἴολος / Aiolos), belonging to or relating to Aeolus or Aeolus, god of the winds in Greek mythology and, therefore, belonging to or relating to the wind. Wind energy has been used since ancient times to move ships driven by sails or operate mill machinery by moving their blades. It is a type of green energy.
Wind energy is related to the movement of air masses that move from areas of high atmospheric pressure to adjacent areas of low pressure, with proportional speeds (pressure gradient). So it can be said that wind energy is a non-direct form of solar energy. The different temperatures and pressures in the atmosphere, caused by the absorption of solar radiation, are what set the wind in motion.
It is a clean energy and also one of the least expensive to produce, which explains the strong enthusiasm for its applications. Of all of them, the most widespread, and the one with the greatest growth, is wind farms for electricity production.
A wind farm is the integrated installation of a set of electrically interconnected wind turbines. Wind turbines are the key elements of the installation of wind farms, which are basically an evolution of traditional windmills. As such, they are rotating machines that usually have three blades, about 20-25 meters long, attached to an axle. The capture element or rotor "Propeller (device)") that is attached to this axis, captures the energy of the wind. The movement of the blades or vanes, driven by the wind, activates an electrical generator that converts the mechanical energy of rotation into electrical energy.
These wind turbines usually measure about 40-50 meters high depending on the orography of the place, but they can be even higher. This is one of the big problems that affects populations from an aesthetic point of view.
Wind turbines can work alone or in wind farms, on land forming wind farms, on the sea coast or they can even be installed on the waters at a certain distance from the coast in what is called offshore wind farm, which is generating great conflicts on all those coasts where wind farms are intended to be built.
The great environmental benefit provided by the use of wind for the generation of electrical energy is given, first of all, by the levels of gaseous emissions avoided, compared to those produced in thermal power plants. In short, it contributes to the planet's climate stability. A significant development of electrical energy from wind sources can, therefore, be one of the most effective measures to avoid the greenhouse effect, since, globally, the electrical sector is considered responsible for 29% of the planet's CO emissions.[20].
As clean energy, it contributes to minimizing global warming. Focusing on the social and economic advantages that concern us in a much more direct way, they are greater than the benefits provided by conventional energies. The development of this type of energy can reinforce the overall competitiveness of the industry and have positive and tangible effects on regional development, economic and social cohesion and employment, although there are discussions about the importance of economic impacts in rural areas.[21].
There are those who consider that wind energy is not an alternative to current energy sources, since it does not generate energy constantly when the wind is not blowing. Intermittency is one of its main drawbacks. The detrimental impact on the quality of the landscape, the effects on birdlife and noise are usually the negative effects that are generally cited as environmental drawbacks of wind farms.
With respect to the effects on birdlife, the impact of wind turbines is not as important as it might initially seem.[22] Another of the biggest drawbacks is the screen effect that significantly limits the visibility and control possibilities that constitute the reason for their respective locations, as a consequence of the alignment of the wind turbines. Added to the visual limitations are the foreseeable electromagnetic interferences in communication systems.
Geothermal energy is that energy that can be obtained by humans by taking advantage of the heat from the Earth's interior.[23].
Part of the Earth's internal heat (5000 °C) reaches the Earth's crust. In some areas of the planet, near the surface, groundwater can reach boiling temperatures, and therefore be used to drive electric turbines or for heating.
The heat inside the Earth is due to several factors, among which the geothermal gradient and radiogenic heat stand out. Geothermal comes from the Greek geo, "Earth"; and from thermos, "heat"; literally heat of the Earth.
Marine energy or energy from the seas (also sometimes called ocean energy or ocean energy) refers to renewable energy produced by ocean waves, tides, salinity and temperature differences in the ocean. The movement of water in the world's oceans creates a vast store of kinetic energy, or energy in motion. This energy can be harnessed to generate electricity to power homes, transportation and industry. The main types are:[24].
• - Wave, wave or wave energy.
• - Tidal energy or tidal energy.
• - Current energy: consists of the use of the kinetic energy contained in marine currents. The capture process is based on kinetic energy converters similar to wind turbines, using in this case underwater installations for water currents.
• - Tidal thermal: it is based on the use of the thermal energy of the sea based on the temperature difference between the sea surface and deep waters. The use of this type of energy requires that the thermal gradient be at least 20 °C. Tidal thermal plants transform thermal energy into electrical energy using the thermodynamic cycle called the “Rankine cycle” to produce electrical energy whose hot focus is the water on the surface of the sea and the cold focus is the water in the depths.
• - Osmotic energy: it is the energy of salinity gradients.
The production of green hydrogen is an innovative technology that can help decarbonize the energy sector and is a promising alternative to fossil fuels, which can accelerate the energy transition in the fight against climate warming.[25].
Although hydrogen can be produced in many ways, the most interesting and promising technology is the production of hydrogen through the electrolysis of water. In this process, electrolysis breaks down water into hydrogen and oxygen by using electricity. If the electricity used comes from renewable energy sources such as wind energy or solar energy, then the entire energy process would be done without generating any pollution. In this case, we would be talking about “green hydrogen”, a clean energy.[26].
The largest green hydrogen plant[27] for industrial use in Europe will be located in Puertollano from 2022 and will serve to reduce natural gas consumption.
What are the advantages of using green hydrogen as part of the energy sector?.
• - Hydrogen is the most abundant chemical element in nature.
• - It is a universal, light and very reactive fuel.
• - Reduces CO₂ emissions.
• - It is produced from renewable energy sources.
• - It is characterized by a high energy density. One kilogram of hydrogen contains twice as much energy as one kilogram of natural gas or other fossil fuels.
• - It is transportable in different states: liquid or gaseous.
• - It is versatile and can be used in innovative ways.
However, green hydrogen also has its own disadvantages, such as:
• - Hydrogen is volatile. It is a flammable substance, making it a dangerous fuel to work with.
• - Electrolysis is an expensive process.
• - Hydrogen is a much lighter gas than gasoline, which makes its storage difficult.
Decarbonization of residential heating systems is a major challenge in countries that currently rely on natural gas. An immediate answer to the problem is to introduce green hydrogen into the process to reduce the carbon content.
Furthermore, in the automotive sector, green hydrogen offers an alternative to the fuels currently used and is proposed as a possible interesting solution for our future. Hydrogen vehicles complement electric vehicles to achieve decarbonization of transportation segments.
Solar energy is a source of life and the origin of most other forms of energy on Earth.[18] Every year solar radiation contributes energy to the Earth equivalent to several thousand times the amount of energy consumed by humanity. By properly collecting solar radiation, it can be transformed into other forms of energy such as thermal energy or electrical energy using solar panels.
Using solar collectors, solar energy can be transformed into thermal energy, and using photovoltaic panels, light energy can be transformed into electrical energy. Both processes have nothing to do with each other in terms of their technology. Likewise, in solar thermal power plants, the thermal energy from solar collectors is used to generate electricity.
There are two components in solar radiation: direct radiation and diffuse radiation. Direct radiation is that which arrives directly from the solar focus, without reflections "Reflection (physics)") or intermediate refractions. The diffuse is that emitted by the daytime sky thanks to the multiple phenomena of solar reflection and refraction in the atmosphere, in the clouds, and the rest of the atmospheric and terrestrial elements. Direct radiation can be reflected and concentrated for use, while diffuse radiation coming from all directions cannot be concentrated. However, both direct radiation and diffuse radiation are usable.
A distinction can be made between active and passive receivers in that the former use mechanisms to orient the receiving system toward the Sun—called trackers—and better capture direct radiation.
An important advantage of solar energy is that it allows the generation of energy at the same place of consumption through architectural integration in buildings. Thus, we can give rise to distributed generation systems in which transport-related losses – which currently account for approximately 40% of the total – and energy dependency are almost completely eliminated.
The different photovoltaic technologies are adapted to get the maximum possible performance from the energy we receive from the sun. In this way, for example, concentrated solar photovoltaic (CPV) systems use direct radiation with active receivers to maximize energy production and thus achieve a lower cost per kWh produced. This technology is very efficient for places with high solar radiation, but currently it cannot compete in price in locations with low solar radiation such as Central Europe, where technologies such as the thin film solar cell (also called Thin Film) are also managing to reduce the price of traditional photovoltaic technology to levels never seen before.
Wind energy is the energy obtained from the force of the wind, that is, by using the kinetic energy generated by air currents.[19] It is obtained through wind turbines that convert the kinetic energy of the wind into electrical energy by means of blades or propellers "Propeller (device)") that rotate a central shaft connected, through a series of gears (the transmission) to an electric generator.
The term aeolian comes from the Latin Aeolicus (ancient Greek Αἴολος / Aiolos), belonging to or relating to Aeolus or Aeolus, god of the winds in Greek mythology and, therefore, belonging to or relating to the wind. Wind energy has been used since ancient times to move ships driven by sails or operate mill machinery by moving their blades. It is a type of green energy.
Wind energy is related to the movement of air masses that move from areas of high atmospheric pressure to adjacent areas of low pressure, with proportional speeds (pressure gradient). So it can be said that wind energy is a non-direct form of solar energy. The different temperatures and pressures in the atmosphere, caused by the absorption of solar radiation, are what set the wind in motion.
It is a clean energy and also one of the least expensive to produce, which explains the strong enthusiasm for its applications. Of all of them, the most widespread, and the one with the greatest growth, is wind farms for electricity production.
A wind farm is the integrated installation of a set of electrically interconnected wind turbines. Wind turbines are the key elements of the installation of wind farms, which are basically an evolution of traditional windmills. As such, they are rotating machines that usually have three blades, about 20-25 meters long, attached to an axle. The capture element or rotor "Propeller (device)") that is attached to this axis, captures the energy of the wind. The movement of the blades or vanes, driven by the wind, activates an electrical generator that converts the mechanical energy of rotation into electrical energy.
These wind turbines usually measure about 40-50 meters high depending on the orography of the place, but they can be even higher. This is one of the big problems that affects populations from an aesthetic point of view.
Wind turbines can work alone or in wind farms, on land forming wind farms, on the sea coast or they can even be installed on the waters at a certain distance from the coast in what is called offshore wind farm, which is generating great conflicts on all those coasts where wind farms are intended to be built.
The great environmental benefit provided by the use of wind for the generation of electrical energy is given, first of all, by the levels of gaseous emissions avoided, compared to those produced in thermal power plants. In short, it contributes to the planet's climate stability. A significant development of electrical energy from wind sources can, therefore, be one of the most effective measures to avoid the greenhouse effect, since, globally, the electrical sector is considered responsible for 29% of the planet's CO emissions.[20].
As clean energy, it contributes to minimizing global warming. Focusing on the social and economic advantages that concern us in a much more direct way, they are greater than the benefits provided by conventional energies. The development of this type of energy can reinforce the overall competitiveness of the industry and have positive and tangible effects on regional development, economic and social cohesion and employment, although there are discussions about the importance of economic impacts in rural areas.[21].
There are those who consider that wind energy is not an alternative to current energy sources, since it does not generate energy constantly when the wind is not blowing. Intermittency is one of its main drawbacks. The detrimental impact on the quality of the landscape, the effects on birdlife and noise are usually the negative effects that are generally cited as environmental drawbacks of wind farms.
With respect to the effects on birdlife, the impact of wind turbines is not as important as it might initially seem.[22] Another of the biggest drawbacks is the screen effect that significantly limits the visibility and control possibilities that constitute the reason for their respective locations, as a consequence of the alignment of the wind turbines. Added to the visual limitations are the foreseeable electromagnetic interferences in communication systems.
Geothermal energy is that energy that can be obtained by humans by taking advantage of the heat from the Earth's interior.[23].
Part of the Earth's internal heat (5000 °C) reaches the Earth's crust. In some areas of the planet, near the surface, groundwater can reach boiling temperatures, and therefore be used to drive electric turbines or for heating.
The heat inside the Earth is due to several factors, among which the geothermal gradient and radiogenic heat stand out. Geothermal comes from the Greek geo, "Earth"; and from thermos, "heat"; literally heat of the Earth.
Marine energy or energy from the seas (also sometimes called ocean energy or ocean energy) refers to renewable energy produced by ocean waves, tides, salinity and temperature differences in the ocean. The movement of water in the world's oceans creates a vast store of kinetic energy, or energy in motion. This energy can be harnessed to generate electricity to power homes, transportation and industry. The main types are:[24].
• - Wave, wave or wave energy.
• - Tidal energy or tidal energy.
• - Current energy: consists of the use of the kinetic energy contained in marine currents. The capture process is based on kinetic energy converters similar to wind turbines, using in this case underwater installations for water currents.
• - Tidal thermal: it is based on the use of the thermal energy of the sea based on the temperature difference between the sea surface and deep waters. The use of this type of energy requires that the thermal gradient be at least 20 °C. Tidal thermal plants transform thermal energy into electrical energy using the thermodynamic cycle called the “Rankine cycle” to produce electrical energy whose hot focus is the water on the surface of the sea and the cold focus is the water in the depths.
• - Osmotic energy: it is the energy of salinity gradients.
The production of green hydrogen is an innovative technology that can help decarbonize the energy sector and is a promising alternative to fossil fuels, which can accelerate the energy transition in the fight against climate warming.[25].
Although hydrogen can be produced in many ways, the most interesting and promising technology is the production of hydrogen through the electrolysis of water. In this process, electrolysis breaks down water into hydrogen and oxygen by using electricity. If the electricity used comes from renewable energy sources such as wind energy or solar energy, then the entire energy process would be done without generating any pollution. In this case, we would be talking about “green hydrogen”, a clean energy.[26].
The largest green hydrogen plant[27] for industrial use in Europe will be located in Puertollano from 2022 and will serve to reduce natural gas consumption.
What are the advantages of using green hydrogen as part of the energy sector?.
• - Hydrogen is the most abundant chemical element in nature.
• - It is a universal, light and very reactive fuel.
• - Reduces CO₂ emissions.
• - It is produced from renewable energy sources.
• - It is characterized by a high energy density. One kilogram of hydrogen contains twice as much energy as one kilogram of natural gas or other fossil fuels.
• - It is transportable in different states: liquid or gaseous.
• - It is versatile and can be used in innovative ways.
However, green hydrogen also has its own disadvantages, such as:
• - Hydrogen is volatile. It is a flammable substance, making it a dangerous fuel to work with.
• - Electrolysis is an expensive process.
• - Hydrogen is a much lighter gas than gasoline, which makes its storage difficult.
Decarbonization of residential heating systems is a major challenge in countries that currently rely on natural gas. An immediate answer to the problem is to introduce green hydrogen into the process to reduce the carbon content.
Furthermore, in the automotive sector, green hydrogen offers an alternative to the fuels currently used and is proposed as a possible interesting solution for our future. Hydrogen vehicles complement electric vehicles to achieve decarbonization of transportation segments.