The term solar energy refers to the use of the energy that comes from the Sun. It is a type of renewable energy.

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The energy contained in the Sun is so abundant that it is considered inexhaustible.


The Sun takes 5 billion years emitting solar radiation and it is estimated that it has not yet reached 50% of its existence.

Solar energy, in addition to being inexhaustible, is abundant: the amount of energy that the Sun pours daily on Earth is ten thousand times greater than that consumed per day in the entire planet.

The received radiation is distributed in a more or less uniform way over the entire surface of the Earth, which makes it harder to use it.SOLAR ENERGYSolar energy, besides being a source of renewable energy, is a clean energy and is an alternative to other types of non-renewable energy such as fossil energy or nuclear energy.

What is solar energy ?

Definition of solar energy

Solar energy is the energy contained in the solar radiation that is transformed by the corresponding devices, in the form of  thermal  energy or electrical energy, for later consumption wherever it is needed.

The element responsible for capturing solar radiation and transforming it into useful energy is the solar panel. Solar panels can be of different types depending on the mechanism chosen for the use of solar energy:

  • Using solar thermal collectors (solar thermal energy)
  • Through  photovoltaic modules  (photovoltaic solar energy)
  • Without any external element (passive solar energy)

Solar energy: what is it and how does it work?

There are two main ways to use solar energy, one as  a heat source  for solar thermal systems, the other as a  source of electricity  for photovoltaic solar systems.


We will focus on this last application. In principle, the way in which sunlight is captured to convert it into electricity is done through  solar or photovoltaic panels.

These solar modules are formed by groups of cells or photovoltaic solar cells that are responsible for transforming the light energy (photons) into electrical energy (electrons).


These cells connect to each other  as a series circuit in order to increase the output voltage of the electricity, that is, whether it will be 12 volts or 24.

At the same time, several parallel circuit networks are connected to increase the electrical production capacity that the panel can provide.

As the electrical current type provided by solar panels is direct current, many times an inverter and / or power converter is used to  transform the direct current into alternating current , which is what we usually use in our homes, jobs and businesses.

Solar energy: Solar cells


When we talk about new discoveries or advances in science we generally refer to the discovery or development of  new and better materials  to make a solar cell .


How does a solar cell work?

A solar cell basically works in the following way:  photons,  which come from solar radiation, impact on the surface of the cell and there they are absorbed by semiconductor materials, such as silicon.
The photons  hit  the electrons freeing them from the atoms  they belonged to. Thus the electrons begin to circulate through the material, and thus produce electricity.


This basic operation is repeated whatever the material used in the solar cell , as  long as of course it has  conductive properties and absorbs light.

The solar cells that make up the solar panels currently available on the market are made of  silicon, a very abundant semiconductor material on the planet , but also difficult to extract and synthesize, resulting in the resulting solar panels being expensive, heavy and difficult to install.

For this reason, scientists from all over the world are continually working on the search for new materials that result in cheaper, more efficient, lighter, thinner solar panels capable of having a greater number of applications, such as being able to pack in a spray.



So we can see that we work in the manufacture of solar cells with materials such as copper, indium, gallium and selenium and even germanium.

The latter gives the best results in efficiency but are very expensive to manufacture, with which  its use is restricted to entities such as NASA .

Also  called double or triple junction cells , which use several aggregate elements, thin layer, using technology sensitized by dye or Graetzel solar cell, hybrid materials, and nanotechnology.

Solar energy advantages and disadvantages

What are the advantages of solar energy?

Solar energy presents a series of very obvious advantages compared to other types of energy, such as that which comes from fossil fuels.

  • Solar energy is a  renewable energy  that takes advantage of the energy provided by the sun. The sun is an inexhaustible source of energy, therefore its energy production is cyclical and never ends.



  • Solar energy is also a  clean energy . In fact, it is considered one of the cleanest energies. To produce solar energy, it is not necessary to spend natural resources or to carry out any chemical or combustion process.
  • It does not emit practically any polluting gases into the atmosphere, it does not contribute to climate change or the greenhouse effect and does not have the problem of the storage of polluting waste. In addition, it does not produce noise pollution, does not cause bad odors or smoke, etc.
  • Solar panels require a large outlay, but have a very long life and hardly require maintenance costs. A solar panel has a  lifespan of around 30-35 years .
  • There are  different types of solar panels  that can be installed with different objectives and at different scales.

For example, photovoltaic solar energy is used to create electricity, solar thermal energy produces heat, while thermoelectric generates heat and electricity on a larger scale.

There is also no doubt that solar energy is a step forward for  self-sufficiency , something that all human beings should aspire to.

For example, the use of solar panels could be very useful in remote and disadvantaged places where the usual electrical installation does not reach.

What are the disadvantages of solar energy?

While it is true that, as we have seen, solar energy has many advantages, it also has some less positive aspects or that still need to be polished.


On the one hand, solar energy requires a high  initial investment . Although they have come down in price, the solar panels and facilities to take advantage of the sun’s energy are quite expensive, although the manufacturers claim that they are amortized in 10 years.

In addition, in many places the rates for self-supply with solar energy are also very high, so obtaining profitability seems complicated.

On the other hand, it is a type of energy that depends on the  weather  or the time of year in which we find ourselves, that is, it does not produce the same amount of energy regularly, although it can be stored for use in times of greater scarcity. Sun rays.

On the other hand, there is also the  landscape impact  caused by solar panels, especially large-scale installations.



It should be mentioned, finally, that many suitable places for the installation of solar energy are arid and desert places  , generally very far from civilization or places of energy consumption, which is why large infrastructures are needed to transport said energy. Energy.

In any case, the disadvantages presented are correctable and are much less important than all its advantages. A pity that, at the moment, not even a small part of what this energy can contribute is used.

How is solar energy produced?

Solar energy is generated when sunlight hits the solar panels, which then convert solar energy into electricity suitable for our homes.

Common ways to generate solar energy

This photovoltaic transformation is the way in which solar energy is produced. In this post, we will analyze in depth how a domestic solar system takes advantage of the sun’s energy.

Solar panels convert sunlight into energy

The process of creating energy from sunlight begins with the most important part of a solar installation: solar panels. A typical solar panel is made of monocrystalline or polycrystalline silicon housed in a metal frame with a glass housing.

When sunlight strikes the thin layer of silicon at the top of a panel, it releases electrons from the silicon atoms.

What is the photovoltaic effect?

The electrons have a negative charge, which means that they are attracted to one side of the silicon cell. This creates an electrical current that is captured by the wiring of the solar panel.

Known as the “photovoltaic effect”, electrons that flow and have been released by sunlight are the basis of electricity generated from solar panels.

The more sunbeams fall on the solar panels, the more electrons will be free, so it is important to take into account factors such as shade and local cloud cover when designing a solar energy system.

The different solar panels produce electricity at different speeds depending on their efficiency and quality. High quality solar panels will often cost a bit more, but in the long term they will save you money because they produce electricity more efficiently.

Investors convert the energy of solar panels into usable electricity

Once the loose electrons have been collected in individual panels, the resulting current is known as direct current.

The electricity we use to power devices, charge electric vehicles and turn on our lights is alternating current. The electricity generated by loose silicon electrons is DC electricity and must be converted to AC power before we can use it.

This conversion is done through devices called inverters. The inverters can be configured as chain inverters, microinverters or power optimizers, but each configuration performs the same general function of converting DC electricity into AC electricity.

Once the DC electricity passes through the inverters and it turns into AC electricity. In this way, solar energy can be used at home or in the general electrical network.

Other solar panel technologies

Most of the available solar panels are made of crystalline silicon, but there are some other types of solar panels that produce electricity from the sun.

Cadmium telluride solar panels (CdTe)


CdTe panels use a material other than silicon to produce electricity. While they do not have very high efficiency ratings (yet), CdTe panels can capture solar energy at shorter wavelengths than silicon panels. In addition, manufacturing costs are low.

Solar panels of copper and Indian diselenide (CIGS)


With higher efficiencies than CdTe panels, CIGS panels are a promising panel option. Unfortunately, high production costs have prevented CIGS panels from reaching the general public. CIGS panels use a different material based on copper to generate electricity.

Organic photovoltaic cells (OPV)

Instead of using an inorganic material such as silicon or copper, OPV cells use thin layers of organic vapor to generate an electric current from sunlight.

OPV cells have not yet been widely used due to low efficiency and short life compared to other panel technologies.

All these solar technologies fall under the umbrella of thin film panels, and are a very small part of the solar energy market   in general. This is mainly because they are not profitable at present.

In the future, these options may be the technologies that dominate solar energy, but for now silicon solar panels dominate the industry.

Where does solar energy come from?


Solar energy comes from the Sun and is converted into useful energy by the uses that the human being gives them.

In it, the hydrogen atoms fuse continuously, transforming into helium. In this process, a portion of the Sun becomes solar energy. Only a part of it reaches the Earth in the form of caloric, luminous and radiant energy.

Plants, using solar energy, combine inorganic substances with carbon dioxide and form an inorganic compound (glucose) that serves as food for herbivorous animals and plants.

In this way, solar energy is converted into chemical energy through the process of photosynthesis. This starts the cycle again.

 Solar energy to be used?

Solar energy has many applications, both in the natural world interacting with all living beings, as in human economy.

The sun gives us all living beings light, energy and heat , but humans get more out of our way of life. With this energy we get electricity, heat, transportation and much more.

Next, we describe the  most important uses of solar energy .

What is the use of solar energy for people?

Apart from the basics that it provides to all living beings,  solar energy serves us for the following in our  current economy and world:


Solar energy is converted into electricity thanks to photovoltaic panels. The foltovoltaic panels are composed of cells or photovoltaic cells.

These cells are built with semiconductor materials, that is, materials capable of behaving as conductors of electricity or as insulators.

The most commonly used semiconductors are silicon and gallium arsenide and are combined with other elements such as phosphorus or boron to generate a difference of negative and positive charges and thus create electricity.

Electricity is defined as the movement of electrons from the negative pole to the positive pole. When the photons of the solar rays excite the electrons, they begin to move towards the positive charges and it is at that moment when the electric current is produced

Hot and cold

Solar energy is also used to produce the heat that we need in our homes, for example for heating or for  heating food .

For this, thermal solar panels are used. They consist of parabolic mirrors that concentrate the solar rays and direct them towards a specific point, usually a tank with water.

The water heats up and flows to our homes where it can be used in the shower, for cooking and even in heating

This technology can also be used to generate cold air like the one that comes out of the air conditioners, this ecological alternative is known as “solar cold”.

The same process is followed as before only adding a heat absorber, lithium bromide, which allows the air to become cold.


Thanks to solar energy we can achieve more sustainable and ecological means of transport.

Although electric vehicles already exist, one could go a step further if that electricity they consume comes from clean and renewable energies. Installing solar photovoltaic panels would achieve the electric power necessary for cars, trams and even airplanes could move.

Artificial watering

The technology of solar energy is also used for irrigation systems in gardens, farms and crops. There are solar water pumps that allow the extraction and transport of water masses thanks to the electricity produced by the photovoltaic solar panels connected to them.

In addition, some of these pumps contain batteries that accumulate the energy to continue working when there is no available solar light.


Solar energy applications

When we say that the application of solar energy is imminent we are not lying, currently there are many solar systems that are deployed on the planet, of course, most of them are concentrated in regions that are exposed to longer hours of sunlight.

With few elements we can make a solar cooker or a flashlight of the same characteristics, everything is a matter of information and knowledge; but if we must be more explicit, we have to point out that  the most important application of solar energy is that which is related to electricity .

If we collect the solar radiation properly we can obtain electricity and thus illuminate our home as to give operation to different appliances; the electricity obtained can be used directly or stored in accumulators and then used at night or on days that lack the presence of the Sun.

This application of solar energy can be carried out thanks to the existence of the well-known solar panels, these are outlined today as the definitive solution to the problem of rural electrification.

They have mobile parts, do not pollute or produce noise, are unalterable over the years, do not consume any fuel and do not need maintenance tasks; the most technological are able to capture solar radiation on cloudy days, but these are already much more expensive than conventional panels.

Solar energy images

Solar energy summary

Solar energy is the energy obtained directly from the sun. The solar radiation incident on the earth can be used for its capacity to heat or directly through the use of radiation.

This type of renewable and clean energy is what is known as green energy. The power of the radiation varies according to the time of day, the atmospheric conditions that dampen it and the latitude. Both direct and diffuse radiation is usable:

    1. Direct: the one that comes directly from the solar focus without reflections or refractions.
    2. Diffuse: the one that is emitted by the daytime celestial vault, thanks to solar reflection and refraction in the atmosphere, in the clouds, and the rest of atmospheric and terrestrial elements.

Advantages and disadvantages

Advantages: much energy is saved, pollution is reduced, it is free, it is an inexhaustible and clean source of energy.

Disadvantages: you can not always count on it, as on cloudy nights and nights, so you have to go to another source of energy. These energy systems are difficult to install and expensive.

What can be obtained with solar energy?

By collecting the solar radiation properly, we can obtain heat and electricity. The  heat  is achieved through the collectors or thermal collectors, and  electricity , through the so-called photovoltaic modules.

Both processes have nothing to do with each other, neither in terms of their technology nor in terms of their application.

  • Harnessing the heat:

    • Obtaining hot water for domestic or industrial consumption
    • To give heating to our homes, hotels, schools, factories etc.
    • To heat swimming pools allowing the bath during all year.
    • The agricultural applications are very broad: With solar greenhouses can be obtained older and earlier crops
    • Purification plants, water desanilization without consuming any type of fuel.
  • Utilization of electricity:

    • It can be used directly or stored in accumulators for use at night.
    • It is also possible to inject the electricity generated in the general network, obtaining an important benefit

Common ways to generate solar energy: 5 ways to generate electricity

Electricity is a phenomenon of great interest. It is present in all aspects of our lives, from the telephones we use, the heating in our homes, and even in the functioning of our brain.

It is difficult to imagine our lives without access to electricity.

On the day we have prepared this article to briefly introduce the main ways of generating electricity at an industrial level.

Hydraulic energy

Hydraulic energy is one of the most efficient ways to generate electricity and, although it generates damage to rivers by dam constructions, it does not generate pollutants that destroy the ozone layer.


Energy is “extracted” from the potential energy stored in water at high altitudes. When falling, the potential energy can be converted into other types of energy, such as the movement of a turbine.

This movement can be used to generate electrical energy through a generator. Then, this electricity is sent to the stations where it will be transformed to be sent to different parts.


Wind power

Wind energy takes advantage of the ability of the wind to move large propellers, which will rotate with the air currents that impact it.


Using basically the same principle used of the old windmills, but with some notable improvements in the design and aerodynamics of the mime.

In addition, it has of course a generator or dynamo which produces electricity which is stored in batteries to be used in the best way.

The electricity created by wind turbines is one of the best forms of energy that exist since it is not contaminant or harmful to the environment and is renewable, so its use is increasingly common in different parts of the world.

Solar energy

Photovoltaic energy is one of the ways to generate electricity with more boom today because you can take advantage of one of the most abundant resources on the planet earth, the sun.


The electricity generated through the sun is produced by solar panels or photovoltaic cells which receive the light energy or the luminosity produced by the sun and convert that light into volts through a chemical process, to then store the energy in 12v batteries and finally convert it to usable 120v voltages.

This type of electricity is in addition to being clean and not generating damage is completely renewable.


Another way to create electric power is by burning fossil fuels derived from oil, such as gasoline and diesel, possessing the same principle as the plants or homemade electric generators.


However, this is a way to generate electricity that on a large scale generates significant damage to the environment and the ozone layer, which are irreparable and therefore other ways of generating electricity are studied.

Despite this, it is one of the most used because it is quite efficient and has a low production cost.

Nuclear energy

The electricity generated by means of nuclear energy is one of the most powerful forms of generation that exists in the world, however it is also one of the least stable, so when leaks are generated or accidents occur with it, it can be finished with major disasters such as Chernobyl in 1986 and Fukushima in 2011.


This energy is generated through the heat created by the decayed atoms of uranium, which will then boil and the steam generated and released under pressure will give movement to large turbines connected to electric generators which turn at high speed generating electricity.

Other types of energy

In this article we have briefly summarized the most common types of energy, but these are not all. For generation at high levels there are other methods, for example:

  • Biomass Generated from organic matter.
  • Geothermal In which energy is obtained from the heat of the earth.
  • Mareomotor. In which the force of the waves of the sea is used to obtain energy.

Why is solar energy renewable?

Is the sun a renewable energy or not?

Indeed,  the sun is a renewable energy , since it can be used as much as you want to obtain energy and  it never runs out .

Naturally, when we talk about renewable energies, including solar energy, and we say that they are renewable or inexhaustible energy sources, we are saying this from a human perspective.

That is, naturally, the energy of the sun will end up exhausted when the star of our solar system drains all its hydrogen fuel, which is the original source from which its energy comes.

However, in the time scale of the human being, this energy is virtually inexhaustible then, solar energy is a reliable renewable resource , so it can be considered without a doubt as a renewable energy.

It is important to keep in mind that, in addition to being a renewable energy, solar energy is also an especially abundant energy in all parts of the planet.

Of course, in the latitudes closest to the equator, as well as the sunniest days, solar energy can be used in greater.

However, even in regions close to the polar circles, and also on cloudy days, energy can be obtained from the solar radiation reaching the surface of our planet, which makes it  one of the potentially most usable energies of those that exist.

Photovoltaic Solar Energy



what is the photovoltaic energy?

In a ‘photovoltaic’ solar cell,  light is  converted directly  into electricity  . Solar cells are thin slices or layers with special electrical properties.

The amount of energy they produce depends on the  incident light and the type of solar module  . All forms of light can be used, but direct sunlight provides the greatest amount of energy. 

The solar cells are connected to each other in  larger solar panels (photovoltaic modules)  . In it, the solar cells are protected between a glass plate on the front and a waterproof plastic film on the back.

How does solar photovoltaic energy generate?

Solar photovoltaic systems convert sunlight into electricity

When we think of this type of energy, one of the first images that comes to us is that of a solar panel. These plates are formed by modules and these, in turn, by  photovoltaic cells .

Its cells are formed by one or more sheets of semiconductor material and covered with a transparent glass that lets solar radiation pass, minimizing heat losses.

Conventional photovoltaic solar cells are made of silicon, which makes them quite efficient, with average yields of 14 to 17%, although they are also more expensive to produce because of their high dependence on the availability of silicon.

They have begun to use other cheaper materials, these cells being called “second generation”, although their yields are approximately 10 to 12%.

For the  concentration systems,  materials that form ” multi-junctions ” are used ,  greatly increasing the yield and reaching values ​​of 25 to 30%.

Research continues to reduce production costs and increase the versatility of the modules, as well as the possibility of using more abundant materials on the planet. In this way, you can choose between different types of photovoltaic cells for the specific characteristics of each installation.

The process of obtaining energy from the sun is simple

Sunlight, composed of photons, affects the photovoltaic cells of the plate, creating in this way, a field of electricity between the layers.

This is how an electrical circuit is generated. The more intense the light, the greater the flow of electricity. In addition, it is not necessary to have direct light, since on cloudy days it also works.


The  photoelectric cells transform solar energy into direct current , and this is usually transformed into alternating current to be able to use the electronic equipment that we usually have in our homes. The device that is responsible for this transformation is called the  inverter .

Thermal solr energy

What is thermal solar energy?

The also known as solar thermal energy, is the process through which energy from the Sun, which in turn becomes heat and can be used for various activities that need heat from domestic use to industrial use.

The solar thermal energy can also be exploited and transformed into mechanical energy and, from it, produce electrical energy.

The process is developed through collectors (plates) of heat waves, located in specific places in the direction of the Sun.



How does solar thermal energy work?

Surely you have wondered how solar thermal energy is obtained and although it seems somewhat complex, it is easy to understand.

The operation of this collection takes place in the solar panels, which capture the sun’s rays, absorbing all the heat.

Through the panels, a fluid is distributed, which can be water, so that the collected heat is transferred to that fluid and this increases its temperature that will be stored at the point of consumption.


Compnenetes necessary to take advantage of the thermal solar energy

To understand better, it is necessary to know each of the parts of the process:

Collectors or solar collectors : plates that capture solar energy and make water flow.

Accumulators : the need to have energy is not always timely due to the variations of time, so it is necessary to have an accumulator that stores the thermal energy.

Heat exchangers : it is essential not to mix both fluids directly (heat and water), so these devices are used for heat exchange but without mixing.

Circulation pumps : they give the fluid the energy necessary for its displacement through the circuit.

Insulation : essential to avoid heat losses to the exterior.

Expansion vessel: absorbs fluid expansions in a closed space due to temperature increases.

What are the advantages of thermal solar energy?

There are different pros that this type of energy use has, among which are monetary saving and preservation of the environment:

  • Autonomous energy from a free and inexhaustible source.
  • Reduce the emission of gases that causes global warming.
  • It reflects savings of electricity consumption by approximately 50%.
  • Additional value to the house or industry.
  • Independent of the high costs of gas and electricity.
  • Its installation cost is recoverable in the medium term.

What are the disadvantages of thermal solar energy?

The disadvantages of this system are usually related to its cost and installation, in addition to the unpredictable condition of the sun:

  • The installation of solar thermal power plants can take several months
  • For the best use, it must be installed in large areas that, for example, could be used for other uses, such as agriculture.
  • The sun is not always there and climate changes do not allow it.
  • When it is used to heat water in domestic use, the times of the year that we have more sun, is when this resource is least needed

Uses and applications of thermal solar energy

Solar energy, transformed into mechanical energy and later into electrical energy, can be used in numerous activities in the home, among them -one of the most important- the production of hot water for industrial use.

These are other important uses and applications of solar thermal energy:

  • Domestic hot water production : this can be profitable for hotel companies or clubs where it is necessary to heat water (25 / 30º) for work use.
  • Clothes laundries : some garments need to be washed with a temperature between 40 and 60 ° so it is beneficial to use solar power plants that can reach these degrees in their capacity.
  • Car washes : the same requirement exists in the tunnels of washed cars, where the optimum temperature is 60º.
  • Industrial washing : in the washing of bottles, car parts, etc., it is essential that the water be at low temperatures that can be achieved with solar thermal energy.
  • Vegetable dehydrators : fruits, vegetables, flowers or grains also require water at low temperatures. Using the power plant alone, hot air is circulated in the product for dehydration.
  • Heating systems : solar energy is also applicable to the heating of spaces that require high temperatures, such as greenhouses as well as poultry and pig breeding pens.
  • Pool heating: solar thermal energy can also be used in the distillation of the sea or pools with the use of solar distillers.

Other applications can be: cooling of buildings, desalting water, heating water for marine species (aquaculture).

Thermal solar energy characteristics

Guide to solar thermal energy.

The sun’s energy is one of the most exploited clean and renewable energies, an energy that is always available and that allows us to produce electricity, but also hot water, which allows us to achieve great energy savings. 

When the sun’s energy is used to obtain hot water, we talk about solar thermal energy, a type of system ideal for our homes that allows us to obtain water, but also heat without spending an exaggeration and provide concrete help to the environment that surrounds us. 

In fact, the carbon dioxide emissions in the air and therefore also the pollution are eliminated. 

To take advantage of the specially made Many different models of these panels are available, even if the most widespread are undoubtedly the flat glass thermal solar panels that are ideal for use in all weather conditions, both summer and winter.


Thermal solar panels are part of a  system that can be natural circulation or forced circulation. 

Solar thermal systems with natural circulation should be considered better from the point of view of energy saving, since they use only the highest luminosity of hot water for their operation without the need to use electricity to reach the pipes of the house. 

In contrast, thermal solar systems with forced circulation need a heat pump that needs electricity to operate, so they are less sustainable from the environmental point of view but they are also much more efficient. 

Obviously nothing prohibits it from integrating thermal solar panels into the gas boiler that  already exists in the house, a certainly much cheaper solution that also offers the security of having the gas available in case of emergency or need. 

Obviously, solar thermal systems have  installation  costs, costs that vary from case to case, but which are roughly around € 5,000. 

Obviously, all those who wish to install a system of this type but are not in possession of the necessary liquidity can request a special loan without forgetting that tax deductions are also provided  .

It is possible to deduct 55% of the cost of installation work, even if as of January 1, 2013, this percentage will fall to 36%.