How Solar Panel Energy Works 2024?

Solar energy is the main source of renewable energy on the planet and numerous ways to benefit from it have been studied. Given its enormous importance, the question arises spontaneously: what are the characteristics of solar energy? It is inexhaustible, it is available to everyone, and above all, it is 100% clean. it does not involve emissions of CO2 or fine dust.

Having underlined the particularities and importance of the source, it is possible at this point to explain how solar energy is used and in what context; this energy source is used for the production of electrical energy (via photovoltaic panels) and thermal energy (with solar panels) through solar radiation.

In recent years, the technological development of solar thermal and photovoltaic systems has reached important levels; together with the fact that attention to the environment has become increasingly important, we can see in cities and general in inhabited centers more and more roofs featuring photovoltaic or solar thermal panels.

How Solar Energy Works

To better understand the potential of this green energy resource, it is useful to know how solar energy is exploited, what potential it has, and what its advantages and disadvantages are.

First of all, it is interesting to know that the sun is an inexhaustible source of energy, the amount of radiant energy that reaches the Earth from the Sun per unit of time and surface area is equal to 1.4 kW/m². 

As mentioned above, it is possible to obtain electricity and heat from solar energy; What are the main methods for performing these functions?

Solar Photovoltaic: 

The main component of the photovoltaic system is the photovoltaic panels, composed of a series of photovoltaic cells, capable of transforming solar radiation into electrical energy thanks to the presence of a semiconductor material, namely silicon. Semiconductor materials, once hit by sunlight, can generate a flow of electric current thanks to the movement of electrons.

Solar Thermal: 

Solar radiation can also be used to heat domestic water or environments, both in residential homes and in companies. The main device of the solar thermal system is the thermal collector: its purpose is to heat a liquid, called heat transfer fluid, which then moves inside the system bringing heat to the desired areas. 

Thermodynamic Solar: 

The thermodynamic solar system is a technology that integrates a heat pump into the solar thermal system. What distinguishes it from other systems that exploit renewable energy is the fact that this system works all year round and throughout the day thanks to the presence of the heat pump which intervenes when solar energy is not available: the innovative technology it uses allows the system to function unconditionally, without being affected by any limitations when the climate is not the best.

Read more: Photovoltaic Storage Batteries

Advantages and Disadvantages of Solar Energy

Solar energy, as already reiterated, has numerous advantages, both in terms of environmental protection and from an economic point of view.

The Sun is a green energy source, as it does not require any gas combustion or CO2 emissions. Furthermore, it does not present geolocalisation problems: the whole Earth is irradiated by the Sun, even if some areas are more exposed.

On The Economic Front, The Advantages are Notable: 

although, for example, the installation of a photovoltaic system is a fairly significant expense, the investment is still amortized within a few years: to give a concrete example, the complete installation of a 3kW system requires a cost of around 6,000 euros, which can be recovered in an average period of 8 years, thanks to the savings on the bill and the tax deductions that encourage the use of these energy supply methods. In addition to this, if you choose the option of a photovoltaic system with storage, it is possible to achieve energy savings of up to 90% on your bill.

Solar Energy Also has Disadvantages:

One of these is that, since solar radiation is not continuous due to the alternation of day and night and climatic events, continuity of production is often not guaranteed. To overcome this problem it is possible to opt for a photovoltaic system with storage, to be able to have electricity available even when the system does not produce it. The solar thermal system, on the other hand, already includes the installation of a storage tank.

Solar Energy in Italy

In Italy, as throughout Europe, in recent years there has been a substantial increase in the use of renewable energy, which has meant that the use of coal, which is very harmful to the environment, has been able to decreased. As regards Italy country, renewable energies covered 36.4% of electricity demand during the last year, while solar energy in Italy in 2021 satisfied 8% of national electricity needs, with production reaching a historical maximum and an increase of 2.1% compared to 2020. Solar photovoltaic therefore represents a share of 21.7% of electricity production from green sources, second only to hydroelectric energy.

Solar Sources Constantly Growing in Italy

The production of energy from solar sources in Italy is constantly growing: Italy is also one of the European states with the greatest exposure to solar rays and therefore investing in photovoltaics is certainly a very efficient solution. If Italy managed to ensure that the percentage of solar energy no longer represents only ⅓ of total energy, it could position itself as a European leader in this sector.

Photovoltaic Systems were Installed in Italy

During 2020, approximately 750 MW of photovoltaic systems were installed in Italy, largely adhering to the promotional mechanism called Exchange on Site managed by the GSE (approximately 57%) and to tax incentives. at the end of the year, the total installed power amounted to 21,650 MW, an increase compared to 2019 of +3.8%. The production recorded in the year amounted to 24,942 GWh, an increase compared to 2019 (+5.3%) mainly due to better radiation conditions.

Solar Energy in Europe

According to official Eurostat data, in 2020 the energy produced in Europe from green sources covered 37% of the electricity needs of EU countries, with solar and wind energy which for the first time in 2021 exceeded the production of electricity from gas. Overall, the European green electric energy mix grew by 3% in 2020 compared to the previous year, with solar PV reaching a 14% share of all electricity produced from renewable sources.

Among the most advanced countries in the energy transition are Austria and Sweden, where clean energy covers over three-quarters of electricity energy needs, while this share reaches around 50% in Denmark, Latvia, Portugal, and Croatia. The last places are Malta, Hungary, and Cyprus, where renewable energies cover just 10% of electricity demand.

How to Exploit Solar Energy

The best option for exploiting solar energy is a photovoltaic system, a system capable of transforming solar radiation into electricity. This process can be used both in the home through residential photovoltaics, and in the industrial and corporate sectors but also for large-scale electricity production.

To store the electricity produced during the day and in summer to distribute it better during other periods, it is possible to install a storage tank of adequate size. Green electricity can also be used to power heating systems such as radiant panel heating, or the heat pump for sustainable cooling and heating of buildings.

Another way to exploit solar energy is a solar thermal system, a system equipped with special solar panels capable of using solar energy directly for heating and the production of domestic hot water. Solar thermal energy is also a completely ecological solution with zero emissions, furthermore, solar thermal energy is also compatible with large systems, suitable for the energy needs of industries, accommodation facilities, hospitals, and condominiums.

The Unit of Measurement of Solar Energy

The design and installation of systems that use solar sources, such as photovoltaic and solar thermal, require adequate knowledge of the energy that can be obtained from the Sun. Considering ideal conditions, for a flat solar panel, i.e. arranged perpendicular to the sun’s rays and without interference from the Earth’s atmosphere, the radiant power per square meter on Earth is 1,366.9 W/m². This means that each square meter of solar module is supplied with 1,366.9 solar watts.

Radiant power is also referred to as irradiance, a unit of measurement that varies depending on the distance of the Earth from the Sun, the Earth’s atmosphere, weather conditions, and the different positions of the Sun during the day. These factors make the ground irradiance different in each area, in fact, according to European Nuclear Energy Agency in Italy the solar irradiance can range from 160 W/m² in the Po Valley up to 200 W/m² in Sicily.

Naturally, there are special instruments for measuring solar radiation, such as the pyranometer and the pyroheliometer. The thermal power generated by solar radiation is measured in Watts or Joules. The electricity produced by a photovoltaic system is measured in kWh, or kilowatts per hour, to know the amount of electricity generated every 60 minutes.

How Solar Energy is Obtained

Energy from the Sun is obtained through photovoltaic or solar thermal panels, through which it is possible to transform solar radiation into electrical energy or thermal energy. In photovoltaic systems, the silicon cells are reached by solar radiation, with a transfer of energy from the photons of light to the electrons present in the conductive material of the photovoltaic panels.

This process generates a direct electric current, which is converted by the photovoltaic inverter into alternating current so that it can be used for self-consumption or transfer to the electricity grid. In photovoltaic systems with storage, the unconsumed electrical energy is stored in specific batteries, in this way it can also be used at a later time, optimizing the efficiency of the system and increasing the self-consumption rate.

A solar thermal system uses solar rays to convert solar energy into thermal energy, through special solar collectors with which the heat convector fluid is heated and the water is heated through the transfer of heat. 

In this way, it is possible to have domestic hot water available without producing CO2 emissions or to heat a property ecologically and sustainably, thanks to the enormous potential of solar energy.