Photovoltaics, which has become increasingly popular in recent years, is a branch of science dealing with the conversion of solar energy into electricity. This transformation takes place thanks to the photovoltaic phenomenon, also known as the photovoltaic effect. It was first noted and described in 1839 by Alexandre Edmond Becquerel, a French physicist and physical chemist. In photovoltaic systems, this effect is used to convert light into electricity, which is needed to power multiple appliances in homes, businesses, and farms.
To be able to answer the question of how a photovoltaic installation works, you first need to know what the phenomenon occurring in a single photovoltaic cell is all about. The so-called photoelectric phenomenon consists of a change in the electrical properties of a cell made up of semiconductors under the influence of solar radiation.
Each silicon wafer consists of two layers, separated by a so-called potential barrier. The upper layer, directed towards the sun, or more precisely, towards the stream of photons which are the smallest unit of light, is negatively doped. This means that there are excessive electrons in it. The bottom layer is positively doped, which means that it is electron deficient.
As a result, an electric field emerges in the barrier area as the energy of a photon incident on the photovoltaic cell causes the release and movement of the additional electrons in the upper layer. This creates a potential difference, i.e. electrical voltage. Once the circuit with an electrical consumer is closed, current flows between the plates.
The efficient operation of a photovoltaic system depends on exposure to sunlight. Therefore, PV panels are mounted on roofs, and in certain cases on the ground, facing south and titled to 30-40 degrees. On flat roofs, PV systems are installed using special support systems that ensure the optimum tilt angle of the PV modules, which translates into improved power generation capacity. Please note that the PV system must not be shaded. This aspect is particularly important in autumn and winter when the sun travels relatively low on the horizon so that any tall trees or neighbouring buildings can cast a shadow on the PV modules and interfere with their operation.
Photovoltaic modules generate direct current (DC). To be able to use this electricity in your home, it needs to be converted into alternating current (AC). This is done by the inverter, which, next to the PV panels, is the most important component of any photovoltaic system.
PV panels generate direct voltage using solar rays. In our sockets, however, there is AC voltage with parameters that correspond to the low-voltage network (230/400 V 50 Hz). To use the electricity produced by the system, the two voltages must be mutually adjusted, and this task is implemented by an inverter.
This device automatically converts the DC voltage to the appropriate AC voltage. The resulting alternating current can be used to power household devices and the surplus can be sent to the power grid and collected in periods of increased demand, which usually occurs in winter when the days get shorter and it gets dark quickly.
However, do not forget that prosumers can collect the surplus electricity stored with the power company at a loss, which is currently 20% or 30%, depending on the capacity of their photovoltaic system. According to the Renewable Energy Sources Act, owners of PV systems whose capacity does not exceed 10 kWp can collect from the grid 80% of the generated energy. Investors, in their turn, whose photovoltaic installations have a capacity between 10kWp and 50 kWp settle a 1:0.7 ratio with the power company, which means that during the balance period they can collect 70% of the stored electricity. However, with a bi-directional meter, it is possible to track the current flow and continuously monitor the amount of electricity produced by your system and collected from the grid. In addition, the inverter is also responsible for monitoring the condition of the system and checking its operation. Inverters also allow for verifying the amount of energy produced by the photovoltaic system, as well as readings on the DC and AC sides.
Due to the growing ecological awareness of our society, photovoltaics are often discussed in the context of choosing forms of heating for modern homes, especially heat pumps. Where does this trend come from? The reason is simple: the two systems complement each other. A heat pump extracts energy from the natural environment; air, ground, or water; but it also needs electricity to work. If this is obtained using a photovoltaic system, the cost of operating the heat pump, and thus heating the house, is significantly reduced. The combination of these two systems thus brings tangible benefits to prosumers, regardless of the season. The surplus electricity stored in the period of greater insolation can be successfully used by the heat pump in winter when electricity production is lower due to less insolation.
When getting to know the principles of operation of photovoltaic systems, also note the possibility of combining the benefits of their use with a solar system. Although the terms photovoltaic panels and solar panels are often used interchangeably, they are completely different types of systems and are intended to be used differently as well. A photovoltaic system, as we already know, is used to convert energy obtained from the sun into electricity. Solar panels, on the other hand, convert solar energy into heat and are capable of heating a water tank to 70º C in just a few hours. If you choose to invest in both systems, you can use the electricity produced by photovoltaics to power electrical water heating devices. The hot water costs will then be significantly reduced.
Systematic increases in electricity prices make investments in photovoltaic systems attractive for a growing number of individuals, farmers and entrepreneurs. According to information made available by the Polish Photovoltaic Industry Association, the Polish market of photovoltaic micro-systems is worth nearly PLN 6 billion. At the same time, there appears to be no change in this trend. Therefore, it is worth getting to know the principles of operation of a photovoltaic system to adjust its power to current needs and take advantage of the numerous photovoltaic subsidies available. This would help to significantly reduce the monthly bills from the energy company and benefit the environment.
The third edition of the My Current 3.0 programme, launched on 1 July 2021, allows for obtaining up to PLN 3,000 for the installation of a photovoltaic system with a capacity of 2 to 10 kWp, which has been commissioned after 31 January 2020. Applications for subsidies of photovoltaic systems should be submitted electronically, through the Generator of Subsidy Applications or GWD for short. The previous two editions of the programme enjoyed great interest from beneficiaries and the pool of funds was quickly exhausted. Therefore, if you wish to benefit from RES in the upcoming years, apply for a subsidy as soon as possible.
Farmers, in turn, may benefit from the Agroenergia programme, with two forms of support. The first one is a non-refundable grant of up to PLN 25,000. The second one is a loan granted on preferential conditions. According to the programme's assumptions, farmers may obtain up to 100% of financing for a photovoltaic system and repay the incurred obligation within the period of up to 15 years.
Entrepreneurs, in turn, may use the Energy Plus Programme as one of the forms of support for investments in RES. Similar to farmers, they can count on co-financing in the form of a loan or a grant. Loan granted to finance a photovoltaic system may not exceed 85% of the total eligible costs, while a grant may cover up to half of the costs. Leasing of photovoltaic installations or loans offered by reputable banks on favourable terms also enjoy a lot of interest from entrepreneurs.
An analysis of market trends to date indicates that the popularity of photovoltaics will remain high in the coming years. This is not only due to consumer behaviour but also to legal circumstances and requirements set by the European Union. In the face of rising electricity costs and falling prices of individual components of photovoltaic systems, investors are attracted by the benefits of renewable energy sources.
For individual investors, the benefits mostly translate into finances. Available subsidies or the possibility to take advantage of thermal modernization allowances provide some opportunities for real savings. On the other hand, entrepreneurs investing in RES, apart from the economic aspect, also work on improving their reputation. For many companies, especially in production, taking care of the environment is an important element of their development path. In this context, photovoltaics are, and will remain, an important development factor, determining market opportunities and increasing the competitive advantage of enterprises.
Anyone who wishes to learn how a photovoltaic system works is invited to take part in periodic webinars and training organised by CORAB and run by experts in the field of RES. Additionally, make the best you can of our knowledge base on our website. We will advise you and share our experience to make your photovoltaic system work efficiently and bring measurable benefits in the form of free electrical power. We know all too well that the profitability of your investment depends on making good choices, based on reliable information. With the experience of CORAB experts, you can be sure that the photovoltaic system installed in your house, farm or company will work trouble-free without any downtime.