How do solar power plants work on photovoltaic panels?

Solar power station (SPS) – is an engineering construction that converts solar radiation into electrical energy. Depending on the type of construction, the methods for converting the energy of solar radiation differ.

In this section, we will consider SPS using photovoltaic modules (solar cells).

Components of industrial SPP and their functions:

• supporting structures (trusses) – is the basis for fixing panels (solar cells);
• photovoltaic modules – convert the Sun radiation into the direct current;
• grid tie inverters convert direct current from modules to alternating current, with industrial frequency;
• management and monitoring system controls the SPS operation and parameters;
• metering system keeps track of the amount of electricity supplied to the external grid.

1. Supporting structures (trusses) – is the basis for fixing photovoltaic panels (solar cells).

A set of metal mountings (rackings) for a ground-based solar power station is designed to create a support system for cells. The set is designed depending on the geodesy of the site, earth orientation as relating to the cardinal directions. On the finished truss, PV modules are placed vertically at a definite angle to maximize sunlight exposure. 

Mountings for solar panels can be made from:

• Galvanized steel – is a budget choice, zinc coating allows steel to be more moisture-resistant.
• Stainless steel – is more expensive than galvanized steel, chromium in the alloy makes such structures stronger and durable.
• Anodized aluminum – the racking has a light weight, high strength. Moisture and UV resistant.

2. Photovoltaic modules – convert Solar radiation into direct current

A photovoltaic module (solar cell) – is a renewable source of electrical energy that converts light energy of the sun into electricity using the photovoltaic effect. They are independent of fuel, do not emit harmful substances, do not pollute the environment and do not produce any noise during operation. They are the most environmentally friendly sources of electrical energy.

There are no moving elements in photovoltaic panels, making them stable, reliable and have a long service life.

Photovoltaic modules (solar cells) are divided into several types depending on the manufacturing method:

• Monocrystalline solar modules – monocrystalline silicon elements. They have the best performance indicators (their service life is more than 30 years). The efficiency factor of a photovoltaic panel based on monocrystalline silicon is 14-17%.
• Polycrystalline solar modules – polycrystalline silicon elements. Service life is more than 25 years. The efficiency factor of a solar cell on this basis is 10-12%. It is the most common type of modules for solar cells.
• Amorphous silicon solar modules – elements do not have a structured position of atoms, therefore, amorphous silicon has poorer semiconducting properties. The efficiency factor = 8%. On the plus side – such panels require less silicon in production and are applied to any surface (glass, metal or other material).

3. Grid-tie inverters convert direct current from modules into alternating current with industrial frequency

A grid-tie inverter is a device that converts direct (DC) voltage from renewable energy sources (PV modules) into alternating (AC) voltage, and transfers it directly to the grid. The inverter synchronizes the output voltage with the external grid voltage.

Thus, the grid-tie inverter converts the DC from the solar cells with the necessary frequency values and phase for interfacing with the fixed network. As a rule, the conversion is carried out using PWM – pulse width modulation.

The inverters are equipped with a built-in tracking system of a solar cells maximum capacity point. This allows to get maximum energy with any external weather changes, and generation to the grid is carried out even in overcast weather.

Grid-tie solar inverters of industrial purpose are used to transfer energy from renewable energy sources to a 3-phase grid. The power of such inverters reaches several hundred kW. Such inverters (conversion stations) are built on a modular approach.

4. The control and monitoring system controls the SPS operation and parameters

SPS operation monitoring - is a process that allows to monitor station operation in real time. The parameters that must be checked, — power, voltage, current, frequency, switches and equipment status. Loads forecasting for several days in advance is also included in the monitoring functions.

5. The metering system keeps track of the electrical energy amount entering the external grid. 

Automatic system for commercial accounting of power consumption - is a technological solution that provides: remote data collection from smart metering devices, transfer of the received information to the operator's personal account, processing of the transferred data with subsequent uploading to information systems – 1C or others.

This is a set of organizational and technical tools that allow to measure the amount of consumed and supplied electrical energy in mutual settlements between the producer and the buyer. It includes the collection, storage, processing and transmission of data received from individual and collective metering devices.

How useful are solar power stations?

How useful is solar energy: from all energy sources it is the most environmentally friendly and 100% inexhaustible. The benefits of solar power stations: a positive impact on the environment, accessibility and inexhaustibility of the source.

Humanity needs energy and actively makes use of non-renewable sources – oil, coal, gas and peat. In a natural way, i.e. very slowly, their reserves continue to form in the bowels of the Earth. This speed does not correspond to the speed of their use and, of course, the extraction of mineral resources worsens the ecological situation.

The best way out – is a transition to renewable energy sources – solar, wind, biogas. Solar energy is developing more actively than others; the geography of using various solar power stations types covers almost the whole world.

Each SPS slows down negative environmental processes. A 1 MW SPS reduces carbon dioxide emissions by 1.3 thousand tons per year. Excess carbon dioxide emissions – are a key driver of climate change on the planet. The more widely solar energy is used to meet humanity's energy needs – the more chances it has to save the planet from destruction.

What is solar energy?

Solar energy – is the most powerful renewable energy supplier. The sun has illuminating the planet for billions of years, and from entire spectrum of solar radiation, light and heat are the most important for all life on the planet.

Each square meter of the Earth receives an average of 342 watts of energy. This is an average value that includes day and night.

The use of solar energy

Solar energy is the most environmentally friendly. Its application does not require significant capital investments, it is actually free, generally available and inexhaustible. The disadvantage of solar power supply is the dependence of the power installations output capacity on the geographic latitude of their installation place, season, time of day, cloudiness, degree of atmospheric pollution. But where the solar energy has been successfully introduced, the sunrays heat the water, supply heat and electricity to homes and offices. The scope of application of inexpensive energy is only expanding as it develops and modern technologies make it possible to effectively use any amount of it.

There is a passive or active use of the sun energy. The passive includes: construction of facilities taking into account the climate, selection of building materials for the solar energy use for lighting, heat supply, air circulation in rooms. However, the active use involves the installation of photovoltaic solar panels, tower SPS, dish SPS and solar collectors.

Of all renewable energy sources, solar is the most widely used and reliable source. Here are some more interesting facts:

• There is also the possibility of covering temporary needs with solar energy. So, a smartphone protective case with solar elements fully meets its energy needs, there are backpacks with solar batteries, solar headphones with wireless Bluetooth communications. Such devices allow to charge many electronic devices through the USB output.

• The space industry is impossible without the use of solar radiation. Thanks to the sun, the equipment of artificial satellites, spacecraft and automatic interplanetary stations operates.

• In the future, the solar converters efficiency (or efficiency coefficient) will only increase due to the use of nanotechnology, introduction of modern developments and results of scientific research.

• In perspective, the solar energy will become the main source of earth's biosphere energy supply.

Of all available methods of receiving the alternative energy, the most common is its generation in solar power stations. The largest solar power station on Earth "Ivanpah" with an area of 13 sq. km. located in California in the Mojave Desert. This station produces 30% of all thermal energy produced in the United States.

Why solar power plants are useful for business:

• free energy source;
• only the initial cost of purchasing solar energy equipment is required to generate solar energy. Many states are promoting the use of solar energy through various government programs;
• service life of solar panels is 25 years and more;
• solar panels and cells are virtually maintenance-free;
• industrial SPPs are automated and require a minimum of maintenance staff;
• when using solar energy, the fuel resources transportation problems are eliminated, the cost of purchasing them disappears, while solar energy never runs out and is generally available;
• SPSs can be built on inefficient free areas: for example, fields with soil not suitable for agricultural needs;
• return on investment rate is higher than in the oil and gas industry.

More than 2 thousand of industrial SPP are operating in Ukraine. Their total capacity is approaching 2.4 GW. Major solar power plants are:

• "Pokrovskaya" (240 MW) in Dnipropetrovsk oblast;
• "Energo-Star" (120 MW) in Kherson oblast;
• "Voskhod Solar" (52.9 MW) in Nikolayev oblast;
• “Dunaiskaya” (43.14 MW) and “Limanskaya” (43.4 MW) in Odessa oblast.

EDS Group has built and commissioned in Ukraine the following SPP:

1. “Solar Park Shirokoye” (19.9 MW), Zaporizhia oblast.
2. “Solen Energy” (19.9 MW), Zaporizhia oblast.
3. “Belozerka” (19.5 MW), Zaporizhia oblast.
4. “Solar Park Veseloe” (16 MW), Zaporizhia oblast.
5. “Foton Energy” (15 MW), Zaporizhia oblast.
6. “Makov-1” (9 MW), Khmelnytskyi oblast.
7. “Sun Energy Mezhyrich” (7 MW), Dnipropetrovsk oblast.
8. Other power plants in different areas.

Large solar power plants in Ukraine are also located in Zaporizhia, Ivano-Frankivsk, and Zakarpattia regions

Solar energy — radiation and light emitted by the Sun. They affect the climate of planet Earth and create conditions for life. What is solar power? This is one of the areas of alternative energy, based on the use of solar radiation to produce energy in some form. The volumes of use are growing: in 1985, the total capacity of the world SPP was 0.021 GW. In 2019, it exceeded 500 GW (3% of global electricity production).

Ukraine is favorably located in terms of solar radiation activity. The territory has indicators from 1400 kW per year per 1 square meter in Kherson region to 1180 KW per year per 1 square meter in Lviv and other western regions. Where are solar power plants being built in Ukraine? In all regions. The highest concentration — in Dnipropetrovsk, Odessa, Nikolayev, Kherson, Zaporizhia regions. The conditional difference in the generation volume between south SPP (in Nikolayev region) and north (in Kyiv or Chernihiv) does not exceed 10%.

Stages of the construction of industrial SPP:

1. Registration of the enterprise.
2. Feasibility study development.
3. Obtaining land titles.
4. Project development.
5. SPP construction.
6. Connection of SPP to external power grids.
7. Commissioning.

The process takes 0.5-1.5 years, depending on the conditions. How are solar power plants arranged? The main elements of industrial SPP are: photo panels (convert the energy of the sun into direct current) and grid tie inverters connected to them (convert direct current to alternating). Inverters are connected to the common grid through a transformer.

There is no concept of an “average check” for the construction of an industrial SPP. The sum of investment depends on the declared capacity, size of the land, other factors. The conditional level of total costs is $1000 per 1 kW of power. The use of equipment of Ukrainian manufacturers is an opportunity to receive additional state benefits. Where to buy solar power plants? In Ukraine, you can buy ready-made SPP of various capacities that already generate energy. You can buy (rent) a land plot and, with the help of companies providing general contracting services (turnkey construction), build a solar power plant from scratch.

Fields of application:

• thermal collectors (water heating);
• solar panels for electrical engineering, electronics;
• SPP: industrial and residential;
• electric transport.

Advantages of solar energy:

• Renewability. The activity resource of the Sun is 6.5 billion years (NASA data).
• Potential. The power of solar radiation is 120 thousand TW. This is 20 times more than the global energy demand.
• Accessibility for almost all latitudes of the planet.
• Environmental friendliness.
• High resource, low operating costs.
• Extensive application. Energy supply in regions where centralized ETL are not available.

Disadvantages of solar energy:

• High costs at the stage of development and implementation.
• Instability: loss in productivity in bad weather, in winter.
• Production of photovoltaic modules is accompanied by emissions of sulfur hexafluoride, nitrogen trifluoride.
• Average power density – 170 W/m2. It is lower than equivalent one for nuclear energy, coal, gas and oil.

Until 2020, Ukraine had one of the highest "green tariffs" in Europe. Investments in SPP paid off on average in 3.5-6 years. Under the new conditions, it is necessary to win the auction for allocation of quotas for guaranteed purchase of energy by the state. The payback period under such conditions will be longer, but the overall profitability will increase: the winners of the auctions receive a 20 year guarantee of the purchase of energy at a fixed price.

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Wind turbine (WPP) - engineering construction that converts kinetic energy of wind into mechanical energy of rotor rotation with further conversion into electrical energy. The main types of wind turbines - horizontal impeller wind turbine and vertical carousel-type wind turbines.

What is the land area required for placement of wind plant?

For a 1 MW WPP, 30-50 ares of land will be required.

Windmills require a small area, but along the wide perimeter there should be no forest plantations and other obstacles to the wind.

Solar power plant (SPP) - engineering construction that converts solar radiation into electrical energy. Depending on the type of construction, the methods for converting the energy of solar radiation differ.

What is the land area required for placement of solar plant?

For a 1 MW SPP, a minimum of 200 ares of land will be required.

They require a larger installation area than a WPP, and there should be no objects shadowing the panels along the perimeter. It is necessary to take into account the orientation of the land plot, the best arrangement of rackings with PV panels will be on the southern slope.

Hybrid WPP/SPP systems - a wind turbine equipped with solar panels with accumulators. Mutual "insurance" of alternative energy sources is provided (the wind at night and in daytime, sun in daytime, accumulator – at any time). The controller regulates the degree of charge of the accumulators and controls the processes of system interaction.

To locate the hybrid plant, depending on the capacity, an amount of land equal to the sum, respectively, of the area for the photovoltaic panels and the area for the wind turbines will be required. The requirements for the landscape are the same: do not shadow the sun and do not obstruct the wind.

Let's compare the features of the earth’s vibra under a power plant in more detail in article