Sometimes it is sun, sometimes it is rain, and sometimes it is clouds. And then night comes anyway. And how to use the sun in such changing conditions? It is very possible that concentrated solar energy is a solution.

Concentrated Solar Energy, What Is It?

This question is valid at the beginning. In our previous post on solar energy, you could find out how huge amounts of energy our star produces and explore the issues related to the operation of photovoltaics and solar collectors. We also mentioned that you can harness solar energy with focusing mirrors. 

How it’s working?

At the outset, we must disappoint you – you will not put up such an installation on the roof or in the garden. In fact, concentrated solar energy is only used in a few countries. Why? Because it takes a lot of sun to generate heat or electricity. Where is the most of it?

Generally, the greatest amount of direct sunlight is around the tropics of Cancer and Capricorn ( here’s a good map ). The leader in terms of the installed capacity of the CSP (short for Concentrated Solar Power) installation is Spain, which has 2.3 GW at its disposal. The United States is in second place, with installations with a total capacity of 1.8 GW. And globally, at the end of 2016, all installations of this type had a total capacity of 4.87 GW. While this is only a fraction of the total global green energy capacity (here are the  latest RES statistics ), this technology has potential. First, let’s check …

How Does Concentrated Solar Energy Work?

You must have played with a magnifying glass once as children, right? But we are not talking about enlarging the letters, but focusing the sun’s rays on various objects (preferably flammable). Even with your own skin, you could see that the temperature at the point of concentration was high enough to burn yourself. In fact, in this video you can see what this temperature can do with various items.

The technology of focusing the sun’s rays was known already in antiquity. Apparently, Archimedes himself constructed a “death ray” from mirrors aimed at enemy ships. Though the MythBusters proved that this would not be a practical weapon, in theory it should still work. Theory is theory, but concentrated solar energy is currently being used to produce clean energy. How?

Mirror, after all, what is the best reflection of the Sun in the world?

The most widespread CSP technology in the world are parabolic mirrors, focusing a beam of sunlight on a special tube. Such tubes (there are usually a staggering number of them) are placed at an appropriate distance from the mirror (at the focal point) so that the working medium contained in them (e.g. thermal oil, molten salts) can absorb as much solar energy as possible. So, in other words, heat up to close to 400 ° C.

Then this hot liquid, giving off heat in the exchanger, heats the water enough to turn into steam, which in turn sets the turbine in motion, which generates electricity. Almost the same as in a traditional coal-fired power plant, except we have no greenhouse gas emissions or air pollutants .

Solar towers like from sci-fi movies

The second most used CSP technology is solar towers . It sounds a bit like a concept from futuristic movies, and it looks a bit like that. And it works by placing mirrors, called heliostats, over a large area. The sun’s rays are reflected from such mirrors (they are movable and align themselves with the sun) and are directed directly at the tall tower. For what?

At the top of the tower there is a tank with molten salts (60% sodium nitrate, 40% potassium nitrate), which, thanks to a focused beam of sunlight, heat up to over 560 ° C (and sometimes up to 1000 ° C). This hot mixture is then used to produce steam and electricity, just like an installation with parabolic mirrors.

Fresnel solar plates and mirrors

There are still two less widespread technologies available. The first is a system of plates focusing solar energy on a receiver mounted on an extension arm that acts as a motor. Inside there are thin tubes filled with hydrogen or helium and cylinders. The concentrated solar energy heats up the entire system enough to expand the hot gases. These in turn set the pistons in motion, and then, through the shaft, the generator produces electricity. Hmm, it’s a bit complicated isn’t it?

The last, but slightly simpler option of using the sun’s rays are the so-called Fresnel mirrors . It is a system similar to parabolic mirrors, with the difference that the sun’s rays reflected from the mirrors heat the working medium (in this case it is usually water) in one larger and longitudinal receiver. Further, the principle of operation is similar. Pictures say more than a thousand words, so take a look.

Great, but what if we have such wonderful solar technologies, if they don’t work when the sun disappears below the horizon, which is when we would most need energy? It turns out, however, that the first two technologies can work around the clock. How it’s possible?

Concentrated solar energy around the clock

The key to solving this puzzle is storing energy in a hot salt mixture. And not for half an hour, but even for several hours. This means that energy from a CSP power plant can be produced around the clock. Fantastic!

Bathed in sunlight, Dubai likes to use solar energy. They already have quite a few solar panels installed there, but a project to build a CSP power plant using two 200 MW solar towers has just started. One of the requirements is to be able to store and generate energy for 15 hours after sunset. The power plant is to be put into operation in 2021, and the electricity it produces is expected to cost around PLN 3.6 ($ 0.95) per kilowatt hour.

Surprisingly, it can be even cheaper. Three CSP power plants built in Chile (to be launched in a few years) will sell electricity for PLN 2.4 per kWh ($ 0.63) without any subsidies. They too will use solar tower technology (two or three) with a 14-hour energy storage time. Their maximum thermal power is over 1 gigawatt, thanks to which they will be able to provide Chileans 7,100 GWh of clean energy straight from the Sun every year. This is enough to power a total of over 2 million homes around the clock! The best part is …

More and more CSP power plants are built

Israel is building one too. And that’s right with the record-breaking 240-meter-high solar tower . Around it, there will be 50,000 mirrors covering over 3 km2 of surface. In 2018, it is to start producing electricity, which will provide 1% of the entire country’s demand.

Apparently not much, but it is always 1% of pure energy more. And this is what the world needs to replace fossil fuels and reduce the emissions of greenhouse gases that heat our planet. And there will be more clean energy, because more installations of this type are already under construction or will be built in Morocco, South Africa, China and Australia. Whatever it is, it is happening and more and more countries are energetically enlightened.

The International Energy Agency (IEA) has estimated that by 2050 more than 11% of electricity will be produced thanks to installations using solar concentrators, which could reduce CO2 emissions worldwide by up to 8%. In turn, the IRENA agency reports that in Europe alone in 2030 more than 4% of power can be provided by CSP power plants even when the sun is not shining. Great, but …

Why write about it, if it will not work in Poland?

Ok, you can think like that, because we are not a solar power (annual radiation in Poland is only 1000 kWh / m2 – in Chile it is over 3 times more), so theoretically, such technologies will not work for us. How about the fact that in the nearby town of Brønderslev, exposed to the sun’s rays, a solar power plant has been operating since last year, using parabolic mirror technology? Can you? You can!

Its thermal power is 16.6 MW, and the mirrors are arranged in 40 rows, 125 meters each. The working medium is a special oil that heats up to 330 ° C. It is successfully enough to produce electricity. But this installation can also be used to generate heat for heating houses. And this option is used by the Danes, which would also be useful here to replace at least a little coal burnt in combined heat and power plants. 

Additionally, the entire installation will be supplemented with a biomass power plant to generate even more electricity from renewable energy. If our government wanted to, it could carry out such projects also in Poland. Because it is green energy that we will have to rely more and more and no “clean coal” technologies will help here. And the more and cheaper renewable sources you choose, the better. How not, how yes!

Solar energy – is electromagnetic radiation of the sun . It is the result of the vibrations of the magnetic and electromagnetic fields. Solar energy obtained from the Sun is highly energetic and available all over the Earth. It can successfully replace conventional energy sources such as natural gas , crude oil , uranium or coal . It is very important from the point of view of environmental protection and obtaining clean energy.

• Why solar energy?
• The use of solar energy
• Photovoltaics
• Solar panels

Why solar energy?

Nowadays, energy demand is mainly met from fossil fuels such as coal, oil and natural gas. However, these are non-renewable resources and one day their resources will be exhausted. In order to be prepared for this moment, we are already looking for alternative energy sources that will cover the demand for it in the future. The ideal solution seems to be energy coming from the sun. The use of this energy does not produce negative effects on the environment , as burning coal or biomass . According to estimates, the sun will continue to shine 4.5 billion years, which is much longer than human life span .

The sun generates energy through the fusion processes of the conversion of hydrogenin helium. These processes take place at a very high temperature , which is produced by the solar core. Energy in the form of solar radiation reaches the Earth, where:

20% is reflected

40% dispersed in the atmosphere – due to gases and dust suspended in the atmosphere,

40% of it finds its way to the earth’s surface and is used to produce electricity and heat .

Solar radiation does not reach every part of the earth with the same intensity and intensity, and this is due to, among other things, the elliptical shape of the planet, which makes the surface illumination uneven. Lighting also changes depending on latitude, season and day. Some of the rays fall directly to the ground, and some are reflected from various obstacles.

Solar panels. Fernando Tomás from Zaragoza, Spain [ CC BY 2.0 ], via Wikimedia Commons

The use of solar energy

Many technical solutions allow you to obtain solar energy. Systems that enable this can be divided into passive (passive) and active (active).

Passive systems use the phenomena of radiation , conduction and convection to convert solar radiation into heat . They are very simple and do not require a lot of money. An example of a simple passive system is a conservatory, where the sun simply heats the glass room. Currently, passive buildings are built that are shaped in such a way that they are able to use the energy from the sun to heat the building as much as possible. The elements that receive energy from the sun can be large windows facing the right side of the world, large glass surfaces, such as glass or concrete ceilings or brick walls .

Active systems convert solar energy into usable energy with the help of specially prepared devices. They are collectors solar and cells photovoltaic. Photothermal conversion takes place in solar collectors, i.e. the conversion of solar radiation into thermal energy. Photovoltaic cells, on the other hand, work on a different principle and the solar radiation is converted into electricity. This process is called photoelectric conversion.

Solar street lighting Jacek Halicki [ CC BY-SA 4.0 ], via Wikimedia Commons

Photovoltaics

Photons are quanta of radiation that are the energy of solar radiation. The frequency of the radiation determines the energy carried by the photon. The conversion of solar radiation into electricity in photovoltaic cells does not require the use of additional mechanical devices, as there is no indirect energy conversion, as is the case in collectors, where heat is converted into mechanical work to result in electricity.

Photovoltaic power plants use devices to control cells and voltage-current converters necessary to transmit the generated energy to the power grid. Photovoltaic cells produce low voltage direct current . The voltage is also largely dependent on the amount of radiation reaching the cell. The generated current is sent to the power grid after passing through inverters which convert direct current into alternating current .

The cells are made of silicon wafers. Siliconis a material that is widely used in electronics and is common on earth. It creates monocrystalline, polycrystalline and amorphous structures. Cells made of monocrystalline silicon are better than cells made of polycrystalline silicon, but the production price tends in favor of polycrystalline silicon, which is much cheaper.

In order to make the production of cells less expensive and to save valuable material, thin-film technology is used. It consists in placing a thin layer of a semiconductoron a base of other materials that are much cheaper. The advantage of this technology is that the cell can be given any shape that will allow the cells to be integrated into the facade of the building or create a cell on a base of flexible materials. Thin-film technology also made it possible to create multi-junction cells. Such a cell is composed of several layers of materials, each of which has different properties for absorbing the spectrum of solar radiation. Since each layer of such a cell is able to absorb a different wavelength , in the end the whole cell works better than one made of one type of material.

Photovoltaic systems, compared to other renewable energy sources, such as wind farms, do not produce the annoyingnoise . Erecting photovoltaic systems does not require transforming the natural environment and changing the land use, because no harmful substances are produced during the production of thermal energy. So there is no environmental pollution or production of greenhouse gases .

Solar power plant, photo pixabay.com

Solar panels

Solar collectors are used to obtain heat from solar energy. They work on a slightly different principle than photovoltaic cells. An important element of the collectors is the absorber , which absorbs solar energy and transfers it in the form of heat to the mechanical element. Solar collectors are divided into different mechanical elements, that is:

liquid collectors,

air collectors.

Liquid collectors are then classified into the following types:

• flat collectors,
• vacuum collectors,
• storage collectors,
• flexible collectors.

The most commonly used for heating water are flat collectors, which consist of a system of flow channels, a heat carrier, which in this case is a liquid , a solar radiation absorber, an outer casing and a thermal insulation layer. The task of thermal insulation is to separate the lower surface of the collector from the housing. From the top, the collector is covered with a transparent glass that allows it to collect sunlight.

Air collectors are divided into the following types:

• with a flat absorber,
• with an absorber with a developed surface,
• with a porous absorber.

The heat is taken in by the air that flows over or under the absorber. In order to increase the amount of heat that can be absorbed, the absorber surface is corrugated. Air collectors have some advantages over liquid collectors, namely the heat carrier does not change its state of aggregation (does not boil or freeze) and has a simple channel structure. The disadvantage is that, compared to liquid collectors, there are resistance to energy transfer from the absorber to the air , which ultimately increases the absorber temperature and leads to heat losses to the environment.

The sun provides enormous resources to generate clean and sustainable electricity without toxic pollutants or emissions leading to global warming.

Solar energy – the power of the sun – is an enormous, inexhaustible and clean natural resource.

Solar energy production is a clean alternative to electricity from fossil fuels.

• no air and water pollution,
• no overall global pollution,
• no risk of jumps in electricity prices,
• no risks to public health.

Solar resource

Only 18 sunny days on Earth contain the same amount of energy as is stored in the reserves of coal, oil and natural gas all over the planet.

Outside the atmosphere, solar energy contains about 1,300 watts per square meter. When it enters the atmosphere, about a third of this light is reflected back into space, while the rest goes towards the Earth’s surface.

A square meter averaged over the entire surface of the planet collects 4.2 kilowatt-hours of energy every day, or the approximate energy equivalent of almost a barrel of oil per year.

Deserts, with very dry air and little cloudiness, receive the most sunshine – an average of more than 6 kilowatt hours per day per square meter during the year.

Converting solar energy into electricity

Photovoltaic (PV) panels and solar power concentrating (CSP) devices capture sunlight and convert it into usable electricity. Roof solar panels make solar energy profitable in virtually every part of our country.

Like roof panels, large-scale photovoltaic projects use photovoltaic panels to convert sunlight into electricity. These projects often have a capacity of hundreds of megawatts, which could include millions of solar panels installed over a large area of ​​the earth. In addition to the scale, the outputs can be increased thanks to special tracking mechanisms that allow the panels to follow the sun and collect light at the optimal angle, which greatly increases the efficiency of the system.

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Solar energy – useful information

Solar energy is the basic source of renewable energy, i.e. one that we do not have to worry about exhausting. As solar energy is one of the most common, cleanest and natural energy sources, it is considered a very promising source. Also because of the economic benefits that are possible from obtaining solar energy.

In recent years, there has been a progressive trend in the use of solar energy by various institutions and households in Poland. We do not have to look far for examples of using solar energy – just pay attention to the roofs of houses in the immediate vicinity. Certainly we will find at least one collector catching solar energy. Increasingly, we also see photovoltaics that power road signs, notice boards and parking meters with solar energy. In Poland, individual use of solar energy is the most popular. Currently, there is one solar farm in the country and it is a photovoltaic farm in Wierzchosławice near Tarnów.

What is solar energy, solar collector or photovoltaics? What are the possibilities of using solar energy in Poland? For what purpose can we obtain solar energy and through what systems? You will find answers to these and many other questions in the article below.

Solar energy in Poland

The amount of solar energy that reaches the Earth in the form of solar radiation is measured by determining the intensity of solar radiation. In Poland, this value fluctuates between about 900 and 1200 kWh / m2. Such values ​​of solar energy are also similar in countries such as Germany or northern France, but greater than in the Scandinavian countries, where solar energy is already obtained on a large scale.

Solar energy allows you to save up to 70% of the costs of heating hot water throughout the year, and in winter, with central heating, up to 60% of the costs of traditional energy. In addition, by using solar energy, we become independent from external suppliers and protect ourselves against fluctuations and increases in the prices of other energy carriers. It is also possible to save on electricity bills by using solar energy to generate electricity.

What about solar energy when it’s cloudy?

As the name suggests, obtaining solar energy is possible only thanks to solar radiation. However, attention should be paid to the fact that solar radiation reaches the earth not only when there is a cloudless sky. Solar energy can be converted continuously throughout the year, and the main difference between a sunny day and a cloudy day is the amount of energy obtained. When the sun is hiding behind the clouds, the efficiency of solar-generating installations decreases, but the collector still produces less heat and electricity.

How can we use solar energy

Solar energy can be used to obtain both heat energy and electricity. However, it should be remembered that if we want to convert solar energy into heat, we need a different installation than in the case of converting solar energy into electricity. Many people interested in solar energy are familiar with terms such as solar collectors, solar panels or photovoltaics. But are we aware of the difference between these terms?

Solar panels

If we are interested in converting solar energy into thermal energy, we must use solar collectors , also known as solar panels. The panels capture solar energy and convert it directly into heat. Depending on numerous conditions, the efficiency of solar energy conversion can reach up to 90%. Solar collectors can be used to convert solar energy into:

• heating water in residential buildings;
• water heating in swimming pools;
• water heating in industrial buildings;
• heating water in enterprises – hotels, restaurants, hospitals, schools;

Support in heating buildings and other rooms (wall and floor heating).

The most common solar panels on the market are flat and tubular collectors. Converting solar energy through flat panels is an easier and cheaper solution. Tubular collectors are a newer generation of panels, which makes it more expensive, but also more effective. A properly performed installation of solar energy panels can cover up to 75% of the annual heat energy demand. In addition, an important aspect is environmental friendliness – solar collectors do not emit dangerous gases or pollutants, they are quiet and safe for the environment.

Photovoltaics

If we are interested in converting solar energy into electricity, we must install photovoltaic (PV) panels, or photovoltaics . Photovoltaics capture solar energy and convert it into electricity in a cell based on silicon. Photovoltaics are connected in parallel or in series to obtain higher voltage. We can use photovoltaics to convert solar energy into:

• road signaling;
• emergency power systems;
• traffic lights;
• small trade machines;
• providing electricity in households;
• and other.

This solar energy installation is connected to the local power grid. The energy produced by photovoltaics is therefore sent through the grid and collected by the apartment building for free when it is needed. The more electricity from photovoltaic electricity is used for self-consumption, the more profitable it is for the owner to use solar energy. Obtaining electricity by converting solar energy is environmentally friendly – photovoltaics do not emit carbon dioxide, noise or other pollutants.

What is the price of obtaining solar energy

Solar power installations are still relatively expensive, even though the prices of solar power systems have fallen by as much as 99% compared to 1976. Installation prices vary depending on the needs, the solar energy system used, the size of a residential building or apartment. Smaller buildings and rooms need less solar energy, fewer panels and therefore cheaper systems. The installation price ranges from approximately PLN 15,000 to PLN 30,000. The operating costs are low and the investment is intended to pay off as soon as possible. However, please note that each individual case is different, so prices are always approximate.

Subsidies and subsidies for solar energy

Since the use of solar energy is environmentally friendly, the European Union aims to promote this type of energy generation. Therefore, there are many possibilities to subsidize the purchase of solar panels. Co-financing for solar energy amounts to 45% gross of a bank loan, but cannot exceed PLN 2,500 per 1 m2 of the total collector area. An important condition for receiving such funding for solar energy is the purchase of collectors with a documented certificate. Such co-financing may be granted to individuals and housing communities. However, it should be remembered that there are many options for co-financing the acquisition of solar energy and it is worth considering each individual case separately.

Green energy

Ecology is an important aspect of renewable energy sources. Solar energy is a clean alternative to sources such as oil, natural gas or coal, and solar power plants are an alternative to nuclear power plants. The conversion of solar energy is safe for both the environment and its users. Solar collectors do not emit any sounds during operation and do not emit dangerous gases into the atmosphere and do not pollute the environment.

For a few weeks now, the day has been getting longer and spring begins today. This means that there will be more and more sun. Therefore, we asked ourselves the question – how to use solar energy?

The movement of celestial bodies, the position of the Earth in relation to the Sun, words unbelievably pleasing to the ear, such as perihelion and aphelion or all these spring-summer-autumn-winter solstices – we will not deal with all of these. For the purposes of this text, we simply assume that the Sun is shining, and because of the cosmic forces and principles in the cosmos, the Sun is sometimes closer to the Earth and sometimes further. And one day its rays fall more vertically on the surface of the Earth, and another day less vertically. First, let’s check …

How much energy does the sun give us?

The question is valid, since the Sun is a free source of energy. Well, inside our nearest star, thermonuclear fusion takes  place , which means that the nuclei of the lighter elements merge into heavier ones. Effect? In one second, the Sun produces a million times more energy than humanity uses in a year (sic!). Anyway, it’s sooooooooooooooooooooooooooooooooooooooooooooooooooooo full of energy.

Fun fact – do you know that the pull of the Sun is 28 times stronger than the pull of the Earth, so a man weighing 75 kg on Earth would weigh 2.1 tons on the Sun (you might find it useful someday in Millionaires).

All in all, solar energy is actually infinite. Yes, the sun will go out, but in a few billion years and we do not have to worry about it (although in the 2007 movie “Towards the Sun” it turned out that the sun is dying before our eyes, so a team was sent to throw a nuclear charge into it and it got them going, but it’s just science fiction and the source of some photos for this text :).

Besides, the sun rises beyond the horizon every day, no matter what. It is not tied to politics, economics, origins and anything else. The sun was, is and will be. If so, it would be good to know how to use this energy. The first way is …

Solar cells

Padają na nie promienie słoneczne, które zamieniane są w prąd. Wydaje się to bardzo proste, ale co naprawdę dzieje się w ogniwie? W ogniwie jest zazwyczaj półprzewodnikowa płytka, najczęściej krzemowa, albo taka z tellurku kadmu (CdTe) lub mieszaniny miedzi, indu, galu, selenu (CIGS).

The sun’s rays falling on the cell, i.e. in fact particles called photons (with energy greater than the width of the semiconductor gap), knock out electrons from the negative part of the plate (n – negative side). In this way, holes, i.e. places with a positive charge, are formed. Both charges are separated by a potential barrier (pn junction), so we deal here with a potential difference. This is what makes the electrons start to move in an orderly manner and voila, thanks to the so-called photovoltaic conversion, the current flows in the device.

Phew, we got through this complicated technical description. It is worth mentioning, however, that the photovoltaic effect was discovered in 1893 by Becquerel. Since then, there has been a huge development of this technology. First of all, their efficiency increases. Depending on the technology used, the efficiency of PV cells ranges from 10 to even 46% (those that can be mounted on the roof usually reach 15-20%). In addition , solar energy is the cheapest source of electricity in 60 countries . No wonder that Al Gore is an optimist for the climate , since the power of solar panels is constantly growing and prices are falling.

Other ways to use solar energy

There is also such a thing as photothermal conversion. It is the conversion of solar radiation energy into thermal energy. There is passive and active photothermal conversion. Passive is one in which the flow of the heat carrier (for example air or heated water) takes place only by convection, while active conversion uses pumps powered by additional energy sources.

The latter type of conversion is in the form of solar collectors (called solar cells). They are used to heat hot water in homes, hotels or swimming pools (sometimes they even support heating). There are flat and vacuum collectors (they differ slightly in construction and efficiency). The largest solar collector system has recently been built in the Danish town of Silkeborg. It consists of 12,436 solar panels, which make it possible to meet 1/5 of the annual heat demand of the entire town with over 40,000 inhabitants. Not bad.

There are also special, mobile focusing collectors, the so-called mirrors that reflect the sun’s rays so as to focus them in one point. For what? Well, to heat the heating medium (molten salts – sodium nitrate and potassium nitrate) in a solar tower. The largest power plant of this type is located in the Mojave Desert in California (and where else ) and has a capacity close to one block of the Bełchatów power plant (392 MW).

There is still the problem of water thermolysis. What is this devil? At high temperatures, we deal with the thermal decomposition of water vapor into oxygen and hydrogen ( hydrogen can be refueled and driven blue ). There is no problem with high temperature in this case, because many mirrors focusing the sun’s rays in one place are enough. The problem is the separation of the gases formed in this way, the more so as they burn again when the temperature is lowered (return to water). Thermolysis is expensive, wastes a lot of energy and has a low efficiency. Solar PV conversion is therefore the best solution when it comes to harnessing solar energy.

Energy from the sun – advantages

The advantages of solar energy are its immutability (the sun rises every day), universality (the earth is bathed in sunlight), unimaginable abundance (as we wrote, in one second the sun produces a million times more energy than humanity consumes in a year) and zero emissions (energy from the sun does not emit any pollutants when it is produced – the solar wind is not pollution)

Solar energy is the energy of the future

But whatever, the future of green energy is primarily solar energy that is converted into electricity. Photovoltaics has been taming the sun for over 60 years, and its power is still increasing and will continue to grow. More than 1/3 of the energy in American sockets comes from the wind  and the sun. And last year, the Chinese became its largest producer , thus becoming the most enlightened nation in the world 🙂

Other sunny news? The greatest visionary of our time – Elon Musk – offers  solar roofs , and Lodz students drive their  car to the sun . By attaching the  socket to a sun-drenched glass , energy can be generated, while the Japanese build  solar farms on the water . After all, in the skies, a solar-powered plane is already flying . In fact, an ecologically and politically inspiring woman in France even builds roads with solar panels . Little?

New technologies will allow us to forget about phone chargers in the near future, because the phones will have a screen made of a special type of cell ( Dr. Olga Malinkiewicz has already patented this technology with the use of perovskites ). There will probably also be photovoltaic paints, clothes with energy-producing elements ( will they be recycled? ). And the solar panels on the roofs of our electric cars will be quite obvious . So – the sun is sending a mass of clean, free and uninterrupted energy towards the Earth. We should therefore use it.

The elemental origin of energy is solar energy. Millions of years ago, the sun’s energy reaching the earth was trapped in coal, oil, natural gas, etc. The sun also owes energy to the wind or the waves of the sea. You can also use solar energy directly by using special systems for the generation and accumulation of solar energy.

Solar radiation is a stream of energy emitted by the Sun in all directions. The measure of the amount of solar radiation that reaches the earth from the sun is the so-called solar constant. It is the value of the solar radiation energy flux density on the surface of the stratosphere and currently amounts to 1.4 kW/m2. 

There are three components of solar radiation that reach the surface of the Earth:

• Direct is coming from the visible solar disc.
• Diffuse is formed as a result of repeated refraction of the elements 
• Reflected atmosphere resulting from the landscape and surrounding reflections.

The energy of solar radiation reaching Earth is 170,000,000 GW. There is, in fact, a relatively simple possibility of using up to 600,000 GW. It’s a lot more than enough.

The Origin And Evolution Of Sun

The Sun formed about 4.7 billion years ago as a result of the contraction of the hydrogen-containing interstellar gas cloud. This contraction, the effect of gravity, the attraction of all masses, caused the heart of the star to warm up. 

When the temperature was high enough, the fusion reactions began, turning some of the hydrogens into helium. So the sun was born. The sun sends a small amount of energy and heats the bodies that are subjected to its radiation. The main source of solar energy is an uninterrupted chain of fusion reactions that convert hydrogen into helium.    

As with its formation, it continues to endure within the sun. Models of the internal structure of stars can be predicted by the evolution of the sun. Thus, it is estimated that in 4.7 billion years, when the hydrogen reserves inside it are exhausted, the heart of the Sun will begin to collapse and its outer layers will stretch-the star will become a “red giant.” The temperature on our planet is going to rise to 20,000 sC! 

The sun will continue to collapse inward and cool down to finally become a “little dwarf”-a small, cold star of enormous mass, about the size of the Earth.

Benefits

Solar energy has several advantages:

• Universal availability; no negative consequences for the environment during operation; no aging of PV installations after 20 years of operation; virtually no reduction in power;
• Minimum operating costs; reduced dependence on energy suppliers in domestic installations.

Uses Of Solar Energy

Solar energy can be used in many ways, both for heating and for electricity generation:

• The passive photothermal conversion process. Solar energy can be used simply to heat the water that flows through a special pipe system. This way of using energy is not suitable for mass installations but is used in farms to heat buildings, supply hot water or pumps.

• The photovoltaic conversion process. Solar cell technology converts solar radiation directly into electricity. At present, photovoltaic cells are mainly made of silicon-based semiconductors. They are characterized by their long service life and reliability. 

Even cells installed 20 years ago do not usually show a significant decrease in power, producing more than 90% of the energy originally produced. Solar cells work best in high sunlight conditions, such as deserts, where land is not used anyway.