For years now, we have become accustomed to seeing photovoltaic panels installed on the roofs of houses, buildings, parking canopies, or even on the ground, in order to produce clean electricity from sunlight. Especially during the current energy crisis, using photovoltaic panels enables us to reduce CO2 emissions and be less dependent on fossil fuels, while cutting costs at the same time. By installing these modules, we can all become active producers of energy and lend a hand in achieving increasingly ambitious goals. But how many people really know how this technology works? How photovoltaic panels are made A photovoltaic panel consists of units called cells. These are usually made of a semiconductor material such as silicon with the addition of the atoms of other elements such as boron and phosphorus. The cells are then placed next to each other on a flat surface and connected together. This system is protected by a special glass cover, which is treated in order to provide maximum energy yield. The panels harness the sun's radiation and not the heat of the air: for this reason, there is no need for a particularly hot climate. Indeed, efficiency is at its best if the temperature of the cells remains below 25°C. Normally, a solar panel has a rather long lifespan, of about 25 to 30 years. The conversion of the sun's rays into electricity takes place inside photovoltaic cells: photons of sunlight striking silicon – to which the other elements have been added – release electrons, thus producing a direct electric current (DC). Since alternating current (AC) is used in homes, it’s necessary to install a device called an inverter, which transforms the current from direct to alternating. In search of the greatest efficiency Today’s photovoltaic panels are far lighter than the models of a decade ago, thus decreasing the weight on roofs or on the ground. Panel mass has dropped to 11 kg per square meter, and the new slimmed-down panels are also easier to transport and install. In addition to weight, the environmental impact has also been reduced: for example, the 3Sun Gigafactory, a genuine "sun factory" that was set up in Sicily in 2010, produces millions of photovoltaic panels each year and also develops techniques and technologies for reusing and recycling the materials from which they are made. Climate change also poses a threat to solar panels because it could reduce their efficiency due to overheating. For this reason, special devices have been researched and developed that distribute the accumulated heat more efficiently. This produces less overheating and therefore less energy loss. The angle and orientation of the panels are also important in maximizing efficiency. They should be adjusted so that the sun's rays are perpendicular to the modules for as long as possible throughout the day and throughout the year. Not all panels produce the same amount of energy When deciding which solar panels to install, attention should be paid to some important details. First and foremost, choosing the right location in order to capture the maximum amount of sunlight. This is easier said than done: shade from other buildings and surrounding plants can also make a difference, as they affect the efficiency of the system. As a high-tech solution, it is also possible to install devices (known as trackers) that change the orientation of the panels. This enables them to "chase the sun" at all hours of the day, in much the same way that sunflowers do. The system is more expensive, but it also generates more energy. Last but not least, there’s the question of geography. Areas that are subject to greater solar irradiance can produce more electricity while latitude can change the angle of incidence of the Sun's rays. So not all areas of the Planet can produce the same amount of energy from the Sun: even just moving 500 or 1,000 kilometers closer to the Equator can produce up to 50% more energy on average, and vice versa. But there is more to it than that: at the same time, the efficiency of a photovoltaic system is also affected by weather conditions. Fog, cloudiness and mist, for example, can reduce the amount of light reaching the panels.
