Guide to Photovoltaic Panels – GreenStyle

There is more and more talk about the installation of photovoltaic panels for the production of electricity. Not only on a large scale, with large plants capable of covering hectares of land of solar panelsbut also for domestic use. In fact, more and more families are installing this solution on the roof of their house to save on the electrical component and become almost autonomous in energy production.

But what are photovoltaic panels and, above all, how do they work? Although they have become widespread only in recent years, the technology of producing energy using the sun has existed for several decades.

It is also useful to remember that solar is a renewable source, therefore perfectly compatible with the objectives to reduce CO2 emissions and other pollutants due to the production of energy with other systems. Below, some useful advice.

Photovoltaic panels: what are they?

The term photovoltaic panel, or more simply solar panel, identifies a complex device capable of transform the light of the sun in electric energy. It is therefore an optoelectronic solution, capable of generating energy by exploiting solar radiation.

Photovoltaic panels are made up of different elements, all of which are necessary to ensure their functioning. In simple terms, a classic panel contains:

• Photovoltaic cells: they are the basic element of each panel, which stores dozens of them, and they are the actual element capable of transforming sunlight into energy;
• Moduli: individual photovoltaic cells produce low levels of energy and so, to provide for typical human needs, they are joined together in modules. The cells are placed side by side and joined on the surface by a grid wiring, then protected by an upper level of tempered glass or Tedlar.

As already mentioned, this structure is an example, to identify the main components of each single photovoltaic panel. In reality, for the production of cells and modules, a much more complex structure is created, made of different laminations of different materials. In any case, the component most present inside the photovoltaic panels is the silicon.

A Brief History of Photovoltaics

As already mentioned, although the diffusion has become more widespread in recent times, that of photovoltaics is not a recent story at all. The intuition came at the beginning of 1800, when Alexandre Edmond Becquerel he noticed a slight electrical flow generated by some metals exposed to the sun. Thus the “photovoltaic effect” was discovered.

A few years later, in 1883, Charles Fritz he created the first photovoltaic panel, combining a layer of selenium with a film of gold. The efficiency was very low, less than 2%, but it was confirmation of the possibility of producing energy by capturing sunlight.

However, it was in the 1950s and 1960s that research made giant strides, also thanks to the discoveries of a few decades earlier by Albert Einstein, on the photoelectric effect. The first commercial photovoltaic modules arrived on the market in 1963, thanks to theJapanese company Sharp.

How energy is produced from the sun

Many will wonder how it is possible that a fixed device, without any moving components as in the case of turbines and rotors, can produce energy. The credit goes to atomic composition of some materials, although the process is really difficult to understand.

To put it simply, it can be said that some minerals – such as silicon – are sensitive tosolar radiation. Hit by sunlight, their atoms see a movement of the electrons which, precisely because they are stimulated, produce a flow of direct current.

It will not have escaped many people’s attention that, for human activities, more and more alternating electric current instead of continuous. It is for this very reason that the solar panel must be connected to a invertera device capable of converting direct current into alternating current.

Types of photovoltaic panels

However, not all photovoltaic panels are the same, also because the technology evolves rapidly, also modifying the efficiency of the various current and future solutions on the market. But what are the main technologies available today?

Monocrystalline

They are the most performing panels available on the market, as they are able to reach an efficiency close to 20%. In other words, these modules are able to convert 20% of the light received into electrical energy.

However, this is about the more expensive solution on the market because, to obtain this high performance, a very laborious process is used which involves obtaining each individual cell from a single silicon crystal.

Polycrystalline

Polycrystalline photovoltaic panels are the most widespread on the market, since they maintain a good efficiency – around 16% – at a lower price.

The difference compared to monocrystalline ones is not only in terms of electricity production, but also in production. Instead of a pure silicon crystal, they are made with a molten silicon casting. This significantly reduces production times and, consequently, costs.

Other technologies

There are other types of photovoltaic panels, less widespread, but increasingly interesting today both for the progress in efficiency and for the variety of sizes. Among the most interesting, we can mention:

• Thin film modules: they are made by depositing a thin layer of semiconductor materials on a glass plate, for rigid panels, or on a plastic plate for flexible ones. This guarantees great versatility, both in production and in applications: curved panels can be used, for example;
• Flexible modules: thanks to proprietary technologies such as heterojunction or the use of microspherical silicon, it is possible to obtain completely flexible panels. This solution is increasingly of interest for integrating photovoltaic systems into everyday devices, such as smartphones of the future.

Accumulation, costs and performance

When talking about photovoltaic panels, especially at a domestic level, the discussion cannot ignore some factors. storage systemto conserve the energy generated, as well as the costs and the performance.

The importance of storage systems

When thinking about photovoltaics to independently produce energy and power your home, one fact often escapes most people: the sun is not present 24 hours out of 24. If the solar panels are not hit by the sun’s rays, such as at night, the energy production will be zero. And during bad weather days, such as in the case of a particularly cloudy sky, the energy that can be obtained is very small.

This is why every photovoltaic system must be combined with a storage system. These are, in essence, batteries that allow you to accumulate the energy produced and use it at your discretion, even at night or on days of bad weather. The storage system is an important investment when you think about photovoltaics.

The latest technologies focus on lithium batteriesbecause they are very efficient at storing and providing energy, which are usually installed in a safe area of ​​the home – such as a covered basement or a dedicated garage. This is because lithium batteries are very delicate, must not be exposed to external agents and, although in very rare cases, could represent a fire risk.

Costs and performance

Ma how much does it cost install a system home photovoltaic? The rates vary from operator to operator and, above all, from the possible availability of state bonuses. Generally speaking, market prices speak of 2500-3000 euro per kW installed, excluding any benefits. Consequently, for a common need of 3 kW, it settles on 9,000 euros. The price includes the photovoltaic panels, the installation on the roof, the adaptation of the electrical system and, in most cases, the installation of storage systems.

And as for the performanceor the actual capacity to produce energy? Much depends on where you are, on the average number of sunny days in your place of residence, on the presence of dust or pollution that could dirty the panels on the roof making them less efficient. To simplify, an approximate calculation can be obtained by dividing the surface area and power by a thousand, then multiplying the result by 100 to obtain the percentage yield.