Photovoltaics - what you need to know

Photovoltaics – what you need to know

Photovoltaics is now quite a hot commodity, both in the energy market and in the construction market. More and more people are deciding to invest in photovoltaic installations . At the same time, the more installations we have, the more questions arise. Especially because in different media, information that may be contradictory often appears. So let’s consider what is worth knowing about photovoltaics.

What is photovoltaics?

From the physical point of view, photovoltaics is such an interaction of light with matter that, under the influence of light radiation, matter begins to generate free electrons. Put simply, an electric current begins to flow in the illuminated material. People have learned to use this phenomenon to power their own power grid. We do it using primarily the most important element of a photovoltaic set , i.e. solar panels.

What are solar panels ?

The photovoltaic panel is the basic element of our photovoltaic system. One photovoltaic panel, depending on the size of such a panel, consists of several or several dozen, and on industrial installations, even several hundred individual photovoltaic cells. Photovoltaic cells are made of silicon. Silicon is a semiconductor. As previously mentioned, it can generate an electric current when exposed to light. If we connect the wires to such a panel, and connect the wires to our electrical installation, we can power the installation using light energy. This is of course quite a short description, but it explains very well how the photovoltaic set works.

Solar cells

A photovoltaic cell is made of silicon, but silicon is not the most efficient material at all. Silicon is mainly used because it is a safe material. Most semiconductors are various compounds of elements, among which we can find elements that are harmful or even dangerous to humans, such as gallium or arsenic, therefore silicon is used for mass production and mass use. However, it is wrong to think that silicon cells are only of one type. We distinguish at least two main types that differ in both the quality of workmanship and the efficiency. The two main types are monocrystalline photovoltaic cells and polycrystalline photovoltaic cells. Monocrystalline photovoltaic cells are made in such a way that, under strictly defined conditions, large individual silicon crystals are grown. It is a difficult and very complex process, which is why such cells are more expensive, although they are also much more efficient. Cells made of polycrystalline silicon, these are cells made of small crystals embedded in a conductive binder.

What should be the power of the photovoltaic installation?

The power of the photovoltaic installation should of course be matched to our needs. This is an extremely important issue, because the methods of billing for the electricity we deliver to the grid and which we get from the grid are strictly defined. In fact, when we have a shortage or excess capacity, it is unfavorable for us. Of course, it can never be perfectly calculated, but the smaller the error, the better for us.

If our photovoltaic sets show a power shortage, it will mean that we will be drawing more energy from the power grid than we will give back to it. It is worth mentioning here that for free from the power grid, we can take 80% of the power we gave to the grid. This means more or less that the installation will pay for itself much slower than if the balance were zero. On the other hand, if the energy surpluses are large, in fact the loan taken out for the installation will be greater, but we will not earn a single zloty for excess energy. The energy from the panels will be given away by us for free.

How to set up a photovoltaic installation?

Photovoltaic installations are so complicated (the same from the point of view of design, calculations and implementation) that it is definitely best to contact the appropriate photovoltaic distributor. In the past, companies basically offered only assembly and sale of panels. Currently, companies provide comprehensive services that concern not only sales and installation, but also making appropriate calculations. When we sign a contact with a photovoltaic distributor for the implementation of a photovoltaic investment, we must remember one important matter. If we already sign a contract for the implementation of the investment, we must ensure that the contract includes a reference to the guaranteed return on investment.

It happened that through design errors, photovoltaic installations could generate losses instead of generating profits.It is mainly about the situation in which we are building a photovoltaic installation with a fairly high power. These types of installations draw so-called reactive power from the network, which is payable, from a certain level of consumption. In most consumer installations, this type of situation is unlikely to occur, but with larger installations, unfortunately, appropriate expansion joints must be used. Then, in fact, we do not pay for reactive power. Unfortunately, not every company is aware of this.Unfortunately, not every company is aware of this.Unfortunately, not every company is aware of this.