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The Solar Energy Portal

Solar Energy

Solar energy is the largest and cleanest source of  renewable energy  that we have at our fingertips to take advantage of it for the benefit of human beings.

Solar energy  reaches our planet every day. Without it, life on Earth would not be possible. It is a strong radiation that results from the vibrations of electromagnetic and magnetic fields. Renewable energy sources can replace crude oil, natural gas, coal, and uranium.

There are many technical solutions that allow you to obtain solar energy. Active systems include solar collectors and photovoltaic cells, which convert the sun’s energy into heat and electricity, respectively. Examples of passive systems are commonly known greenhouses: large glass surfaces or concrete ceilings that allow heating a specific space.

Humanity has high hopes for this type of energy. Scientists believe that the Sun will last about 4.5 billion years, much longer than our species lives on Earth.

Solar energy definition: What is solar energy?

Next we are going to define what is solar energy. The  energy of the sun  is the electromagnetic radiation of the Sun. It is the result of the vibrations of the magnetic and electromagnetic field. Solar energy obtained from the Sun is very energetic and is available all over the Earth. It can successfully replace conventional energy sources such as natural gas, oil, uranium, and coal. This is very important in terms of environmental protection and clean energy generation.

Solar Energy

How does solar energy work

Solar energy is a renewable resource that can be used to generate electricity or heat. Solar panels, also called photovoltaic cells, convert sunlight into electricity. Solar thermal collectors and solar hot water panels absorb sunlight to generate heat.

What are the advantages and disadvantages of using solar energy?

Like any new branch of science and technology, it raises a bit of controversy among people who have never had contact with it. Experts argue, however, that the use of alternative energy sources is a necessity in light of the constant increase in demand for electricity and the constant use of resources from non-renewable energy sources.

The advantages of solar energy

One of the biggest advantages of solar power plants is that they use a completely free renewable energy source, which is solar radiation, to generate electricity, which is produced in practically all environmental conditions, even when it rains or is cloudy in the Darling.

Advantage number 2 is that this technology is universal, because correctly selected modules can be installed almost anywhere: on the roofs of single-family houses, industrial plants, or on separate components. Properly installed solar batteries are largely fault-free and maintenance-free as they have no replaceable mechanical parts.

The cost of obtaining electricity with solar panels is also much lower than in a traditional and conventional power plant. Obtaining energy does not contribute to the emission of harmful substances into the atmosphere, which allows us to really protect the environment in which we live, and this in turn translates into the quality of our daily operation.

Disadvantages of solar energy

Skeptics see the initial investment cost as the main disadvantage of this solution: the purchase and installation of solar batteries is a significant expense. The second disadvantage, which is mentioned often, is the dependence on changing solar conditions. In view of the changing weather conditions, it is necessary to use the net metering system or indulgences specially designed for this purpose, so that it is possible to properly balance the use of accumulated energy.

Due to the relatively low energy flux density, PV requires large areas to be used to generate more power, which can sometimes be impossible due to local terrain conditions.

The topic of solar energy is definitely worth delving into, because it is certainly a great step towards a better future and a more effective use of natural resources. Focusing on  renewable energy sources has  positive consequences on many levels: economic, ecological and social.

What examples can we give of uses and applications of solar energy?


By solar energy we understand the energy, thermal or electrical, that is produced by directly exploiting the energy radiated by the Sun towards the Earth. Every instant, the Sun transmits 1,367 watts / m2 to Earth. Since this energy is free, clean, abundant and continuously available, various technologies have been developed for its exploitation.


The main existing technologies for the generation of energy from the sun: the solar panel (or thermal collector) that uses the sun’s rays to heat a liquid with special characteristics (water and antifreeze / anti-boil), contained in its interior that releases heat , through a heat exchanger, to the water contained in a storage tank, and the photovoltaic panel that takes advantage of the properties of particular elements to produce electricity when it is stimulated by light.

Thermal solar collectors

The thermal collectors can be of natural or forced circulation; the former use the convective movement of the liquid contained in the panels to allow its circulation within the panel-heat exchanger system. In this case, the storage tank containing the heat exchanger must be higher than the panel.
Forced circulation systems, on the other hand, use a pump that circulates the fluid inside the exchanger and panel when the temperature of the fluid inside the panel is higher than that inside the storage tank, which, in this case, is lower than the panels.

Systems of this type are more complex from the point of view of controls and equipment used (pumps, temperature sensors, three-way valves, control units), but they allow you to place the storage tank, even large, practically where you want , for example on the floor and not on the ceiling where Weight problems would make placement difficult.

Photovoltaic solar panels

Solar modules convert sunlight directly into electricity. These panels take advantage of the photoelectric effect and have a conversion efficiency of up to 32.5% in laboratory models. Having no moving parts or other, these panels require very little maintenance. Basically, they need to be cleaned periodically. The estimated useful life of photovoltaic panels is about 30 years. The main failures of these systems are the cost of the panels and the energy storage.

High-efficiency photovoltaic solar panels have a very high cost and are currently used only in particular situations. Photovoltaic panels with an affordable cost (for large plants) have an efficiency between 14 and 16%. The second problem with this type of plant is that energy is produced instantaneously and cannot be easily stored.

Thanks to legislation that provides financial incentives to install a photovoltaic system and the possibility of selling excess energy produced to the transmission grid operator, Germany ranks first in Europe for electrical energy produced by solar energy: such however , the quantity satisfies only 1% of the German national demand and is completely insufficient to support the increasing trend in energy demand.

Similar initiatives, commonly known as the Energy Account or Feed-in Rate, have been undertaken by several European countries, the last being Italy in chronological order, through Interministerial Decree 07/28/2005 published in the Official Gazette no. 181
of 05/08/2005, often called the Scajola Decree, following the minister in charge of the Ministry of Productive Activities at the time of its issuance.


Solar panels are currently used to provide hot water and heating to homes and small complexes. Attempts were made to build solar power plants that, using turbines, would convert stored heat
into electricity, but these experiments have essentially failed due to the low performance of these plants compared to high management costs and the discontinuity of power supply.

Solar modules are used specifically to power devices far from electrical networks (space probes, telephone repeaters in high mountains, etc.) or with such low energy requirements that a connection to the electrical network would be uneconomical (luminous road signs, parking meters, etc. .). Obviously, these devices must be equipped with accumulators capable of absorbing the electrical current produced in excess during the day to power the equipment at night and during cloudy periods.

Photovoltaic modules are also heated by infrared (invisible) radiation from the sun’s rays, and therefore are delivered even in cloudy and rainy weather. However, the amount of energy supplied is variable and difficult to predict and it is not capable of guaranteeing continuity in the current supply, unless it is a production with a large safety margin above the annual peak of demand. Therefore, solar and wind energy are currently auxiliary systems that are activated when the demand load exceeds the average levels (in the daily and summer peaks for the air conditioning systems).

kwh. In practice, the citizen pays the difference between what he consumes and what he delivers to the electricity company. If the balance is positive, it is credited. Similar legislation has also recently been obtained in Italy: in fact, on September 19, 2005 the so-called “energy account”, DL 387/2003 (which transposes the European directive 2001/77 / CE) came into force. Solar energy supplies only 1% of the energy produced in Germany (equivalent to 2-3% in Italy); and, therefore, it is not a primary source of energy policy. Wind is the least expensive energy (per kWh), but it probably cannot create similar levels of employment.

What are the types of solar energy used to generate electricity and heat?

The  solar energy  can be used to generate heat and produce hot water or electricity, in the first case to speak of  PV systems  while the second is  solar thermal  .

The  types of solar energy  or  technologies  that allow to take advantage of the energy coming from the solar rays are: the  thermal solar panel  , the  solar panel  , the  concentrating solar panel  .

Solar thermal

The  thermal solar panel  is the technology that uses the sun’s rays to heat the domestic water that it contains in a special storage tank.

Used in commercial and domestic contexts, this system works through a  solar collector  , with which a  special  heat transfer fluid is heated   inside the pipes, characterized by insulating material that prevents overheating of its components.

The  thermal solar collectors  can be differentiated into two types:  natural circulation and forced  .

In the first case, the storage tanks that contain the heat exchanger are located on the heat panels through which the liquid circulates, while in the second case a pump is used to circulate the fluid in the exchanger and in the panel. , while the Tank is located lower than the panels.

The use of  solar thermal energy to produce  essential energy to heat and cool the devices allows a clear reduction in the use of air conditioning and space heating systems, reducing dependence on fossil fuels for the benefit of the environment.

Solar photovoltaic

The  photovoltaic panel  takes advantage of solar radiation to produce electricity through some semiconductor elements stimulated by light.

More specifically, these are  photovoltaic cells made of silicon  that allow you to convert sunlight into electricity.

This happens through electrons, which, when light hits semiconductor materials, are channeled and thus produce electrical current.

Although this type of  solar energy system  does not work continuously but only in the hours when sunlight can be used, it is capable of meeting the needs of mountain tanks and isolated areas thanks to its high production.

Concentrated solar energy

The  concentrating solar system  uses some  parabolic mirrors  to produce electricity from the sun’s rays and provide heat at high temperatures.

Through the  concentration of solar panels  , these plants concentrate all the energy in a receiving tube that contains the heat transfer fluid that transfers it  to steam turbines to  convert it into electrical energy.

In addition to the parabolic mirror system, called  point concentration  , which is the most widely used,  concentrating solar energy  can be used as  flat mirrors placed on the ground  through which the sun’s rays are directed towards the top of a tower (  central tower system  ).

The  concentrating solar system  can also have  linear parabolas,  that is  ,  formed by  parabolic tubes  , therefore without cover, whose function is again to heat the fluid contained in the pipes.

In all its applications,  solar energy  offers innumerable  economic benefits  , in addition to guaranteeing respect for the environment.

Here are the  main advantages and disadvantages  to consider before installing a  system that uses solar energy  .

Self-consumption and solar energy

Self-consumption? This means that it uses the energy that your solar panels produce when they are produced, without injecting it into the grid through the meter. Increasing this self-consumption is easier than you think.

What is self-consumption?


Solar panels mainly produce energy during the day, between 11 am and 3 pm with a peak around 1 pm When most of us are not at home … It also happens, for example, in summer, that they produce more energy than the one we need. Consequence? We never use 100% of the energy produced for our  own consumption  .

And that is exactly what self-consumption means: use the electricity that is produced on your roof yourself. Our self-consumption is usually estimated at 30%. The electricity that is produced in excess is dumped into the grid

However, it is possible to increase your self-consumption. And that’s very interesting for more than one reason …

The benefits of self-consumption

Optimizing  your own consumption offers many advantages:

> It consumes less energy from the grid.

> Save on your energy bill thanks to  the ‘partial compensation’ pricing method  . This means that you pay network rates that are based on your actual consumption from the electrical network rather than a fixed prosumer rate. The more you use it, the less you buy from the grid and therefore the lower your energy bill.

Increasing your self-consumption is essential to optimize your investment.

How to increase your self-consumption?

There are several options, which can be combined with each other, to coordinate the production and consumption of electricity.

1. Run your appliances between 12 noon and 3 in the afternoon

Do you usually turn on the washing machine, dryer and dishwasher in the afternoon or at night? If you have solar panels, you better do it during the day as much as possible. That way, you can increase your self-consumption by about 10%.

Almost all household appliances today have a  scheduling function  and can therefore be turned on during your absence.


2. Heat your water during the day

This also applies to your  electric boiler. It usually appears at night. However, you can reprogram it to do so during the day so that you can make the most of the energy your solar panels produce.

3. Install a household battery


A household battery is one of the most efficient ways   to increase your self-consumption.

With a household battery you can store energy and use the energy that was produced during the day at night. Result: it consumes between 50 and a maximum of 80% of its own electricity production instead of 30%.

It is true that investing in a home battery has advantages and disadvantages (the profitability is not perfect yet due to the still high price), but that could be completely different in the near future. By the way:

4. Connect your solar panels to a heat pump

A heat pump gets about 2/3 of the heat it supplies from its surroundings (ground, air) and 1/3 of the electricity it uses.

Electricity that you can produce yourself with your solar panels! It is a matter of increasing your self-consumption a little. Of course, your solar panels will produce more energy in the summer when you need less heat… So it’s not a silver bullet.

However, the fact is that solar electricity is cheaper and guarantees profitable heat production in winter. Because in fact, solar panels also produce energy in winter!

5. Charging your electric car

The installation of a  charging station  as a complement to your installation of solar panels can be interesting to increase your self-consumption if you have an electric car or are thinking of acquiring it.

Over time, electric cars will also be  able to support or even replace  a  battery  . Especially if your car is parked at home during the day (  work from home  , freelance, fixed hours, weekends, …). The battery can be charged during the day and at night, when the electricity consumption in your home increases, your car battery can return electricity. We call this ”  bidirectional charging  “.

With a domestic battery you can increase your self-consumption from 30 to 50 and even 80%!

Meanwhile, you can use the energy that your solar panels produce during the day to charge your car at the same time, whether you work from home, for example, have sliding hours or use your car mainly at night and take a mode of different transportation during the day. .

When do I best use the energy from my solar panels?

You’ve probably figured it out by now: to increase your self-consumption, you need to use as much electricity as possible during the day, when your PV modules produce the most energy. Ideally, do it  between 11 a.m. M. Y 3 p  . M.