Solar energy: an inexhaustible source of energy
Solar energy is a technology for generating electrical energy or thermal energy by converting solar energy. The generation of electricity by converting solar energy is also known as solar power or photovoltaics.
The sun is an inexhaustible source of energy. Solar panels can be placed on the ground as well as on the roofs of buildings. Unlike some other methods of energy production photovoltaic systems do not produce any noise pollution. In addition, compared to other methods of energy production, the systems require relatively little care and maintenance. It is enough to wipe snow or dust from the solar modules from time to time. If the modules are mounted at an angle dust is even removed by the rain on its own.
Solar energy can be used anywhere in the world and in all system sizes: It starts with an outdoor backpack for charging a smartphone and ends with solar fields several hectares in size that can supply entire industrial areas or cities with solar power. Solar generation is accessible to everyone – to citizens for powering their own homes, to farmers for powering their fields, or to businesses and public institutions.
Unlike traditional energy sources, such as coal or gas, solar is available everywhere. Continuous sunny weather with direct sunlight is not essential to generate energy – even cloudy skies generate electricity, although not as effectively. A common misconception is that ambient temperature must be high for solar power generation to be practical. This is not the case at all – solar power generation is used just as successfully in hot countries under the scorching sun as in cold regions of Central Asia. By the way, thanks to the smooth surface of the protective glass on the panes, a small amount of snow usually slides off the modules by itself.
The term “photovoltaics” comes from the Greek photos – light – and volt – a unit of electrical power named after Alessandro Volta. This term is very common in international communication, as well as the short form – PV. It is a method of generating electrical energy in which photovoltaic cells convert the energy of the sun into electricity.
The solar power plant is a single object to produce electrical energy using the sun. In this case, the installed capacity of the solar power plant can range from a few watts (in a pocket calculator or other low-power electronic device) to large solar farms of between 500 megawatts and one gigawatt, which is the size of nuclear power plants. As a rule, each solar power plant has the same composition of equipment, only the characteristics of the equipment differ depending on the power required by the consumer and the type of voltage. Objects to produce solar power with lower power are located on the roofs of educational institutions in our project.
Components of solar power plants are as follows:
Solar modules – a group of semiconductor devices (photocells) that convert solar energy into direct electrical current. A module consists of many solar cells. Modules are manufactured with different parameters and properties depending on the number of solar cells, their size and the technology used. Solar modules usually have a weight between 13 and 25 kg and reach an average size of 1 x 1.5 x 0.3 meters. They last for about 25 years.
The main material used in the production of solar cells for solar modules to date is silicon. There are different types of solar cells in the solar modules – monocrystalline, polycrystalline and heterostructured.
The installed capacity of a solar power plant describes the value of active electrical power that a solar power plant can generate at a given time. The installed capacity depends on the number of solar modules used in the power plant and the capacity of each solar module. For example, a single solar module can have 100 W as well as 350 W of installed capacity, even if both modules are the same size. The capacity or power of the module depends on the solar cells used, its production technology and several other factors.
The solar inverter is a semiconductor device that converts the direct current generated by the solar module into alternating current. In this case, voltage converters can be installed as part of the inverter to obtain the voltage level required by the consumer.
Controller – a microprocessor-based device, a kind of “brain” of the solar system, which controls and monitors the operating modes of the solar power plant and switches the power supply of the consumer between the solar power plant / battery (if any) / central power supply (if any), performs battery charge control and inhibits the overload of the consumer power system. In the industrial solar power plant, instead of the controller, a higher-level control structure is used to monitor the solar power plant.
Compared to the controller, the monitoring system of a solar power plant is a structure for managing a large (industrial) network or a local solar power plant, therefore a higher level. The system has both hardware solutions – relay protection and automation, telemechanics, electricity meter system, sun tracking system and dispatcher system of the solar power plant (controlled by the dispatcher).
Battery – electrochemical device that allows electrical energy to accumulate for a long period of time, in order to release it to the consumer during the required periods. The most commonly used technologies in solar installations are lead-acid and lithium-ion batteries. These batteries are then often referred to as solar storage.
Watt (international designation: W) – a unit of measurement for power, including active power and full power of alternating current. The unit is named after James Watt, the Scottish-Irish inventor and engineer.
1 watt of installed power of a solar power plant is the value of the peak active electrical power that a solar power plant can produce at a given time. 1000 watts is one kilowatt, 1000 kilowatts are 1 megawatt, and 1000 megawatts equal 1 gigawatt.