The influence of painting elements on the efficiency of a solar battery. Balance the efficiency of solar panels. Service life and payback of solar panels

Alternative energy is developing to its maximum in Europe, showing its promise with results. New types of solar panels are appearing, and their efficiency is increasing.

If you want to ensure the operation of an industrial building or residential premises using solar energy, you must first understand the differences between the equipment, because for different climatic zones they are used different types solar panels.

The vast majority of solar panels are physical sense photoelectric converters. The electrical generating effect occurs in the place semiconductor p-n transition.

It is silicon wafers that form the basis of the cost of solar panels, but when using them as a round-the-clock source of electricity, you will have to additionally buy expensive batteries

The panel consists of two silicon wafers with different properties. Under the influence of light, one of them develops a lack of electrons, and the other - an excess of them. Each plate has copper conductor strips that are connected to voltage converters. An industrial solar panel consists of multiple laminated photovoltaic cells bonded together and mounted on a flexible or rigid substrate.

The efficiency of the equipment depends largely on the purity of the silicon and the orientation of its crystals. It is these parameters that engineers have been trying to improve over the past decades. The main problem with this is the high cost of the processes that underlie the purification of silicon and the arrangement of crystals in one direction throughout the panel.

Each year, the maximum efficiency of various solar panels varies by big side, because billions of dollars are being invested in research into new photovoltaic materials

Semiconductors for photovoltaic converters can be made not only from silicon, but also from other materials. The principle of their operation does not change.

Types of Photoelectric Converters

Industrial solar panels are classified according to their design features and the type of working photovoltaic layer. There are these types of batteries based on the type of device:

flexible;
hard.

Flexible thin-film solar panels are gradually occupying an increasingly large niche in the market due to their mounting versatility, because they can be installed on most surfaces with a variety of architectural forms.

The actual characteristics of solar panels are usually lower than those indicated in the instructions. Therefore, before installing them at home, it is advisable to see a similar completed project yourself.

Based on the type of working photovoltaic layer, solar batteries are divided into the following types:

Silicon:
- monocrystalline;
- polycrystalline;
- amorphous.
Tellurium-cadmium.
Based on indium-copper-gallium selenide.
Polymer.
Organic.
Based on gallium arsenide.
Combined and multi-layered.

Not all types of solar panels are of interest to the general consumer, but only the first two crystalline subtypes. Although some other types of panels have high efficiency, they are not widely used due to their high cost.

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Silicon photovoltaic cells are quite sensitive to heat. The base temperature for measuring power generation is 25 °C. When it increases by one degree, the efficiency of the panels decreases by 0.45-0.5%.

Characteristics of silicon-based panels

Silicon for solar cells is made from quartz powder - ground quartz crystals. The richest deposits of raw materials are in Western Siberia and the Middle Urals, so the prospects for this area of solar energy are almost limitless. Even now, crystalline and amorphous silicon panels already occupy more than 80% of the market. Therefore, it is worth considering them in more detail.

Monocrystalline silicon panels

Modern monocrystalline silicon wafers (mono-Si) have a uniform dark blue color over the entire surface. The purest silicon is used for their production. Monocrystalline solar cells have the highest price among all silicon wafers, but also provide the best efficiency.

Large monocrystalline solar panels with rotating mechanisms fit perfectly into desert landscapes. There are conditions for maximum productivity

The high cost of production is due to the difficulty of orienting all silicon crystals in the same direction. Due to these physical properties of the working layer, maximum efficiency is ensured only with a perpendicular incidence sun rays onto the surface of the plate.

Monocrystalline batteries require additional equipment that automatically rotates them during the day so that the plane of the panels is as perpendicular to the sun's rays as possible.

Layers of silicon with single-sided crystals are cut from a cylindrical block of metal, so the finished photovoltaic blocks look like a square rounded at the corners.

The advantages of monocrystalline silicon batteries include:

High efficiency with a value of 17-25%.
Smaller equipment area per unit of power compared to polycrystalline silicon panels.
Sufficient efficiency of electricity generation is ensured for up to 25 years.

There are only two disadvantages to such batteries:

High cost and long payback.
Sensitivity to pollution. Dust scatters light, so the efficiency of solar panels covered with it sharply decreases.

Due to the need for direct sunlight, monocrystalline solar panels are installed mainly in open areas or at heights. The closer the area is to the equator and the more sunny days it has, the more preferable it is to install this particular type of photovoltaic elements.

Polycrystalline solar cells

Polycrystalline silicon panels (multi-Si) have a blue color that is uneven in intensity due to the diversified orientation of the crystals. The purity of silicon used in their production is slightly lower than that of monocrystalline analogues.

Multidirectional crystals provide high efficiency in diffuse light - 12-18%. It is lower than in unidirectional crystals, but in cloudy weather conditions such panels are more effective.

The heterogeneity of the material also leads to a reduction in the cost of silicon production. The purified metal for polycrystalline solar panels is poured into molds without any special tricks. In production, special techniques are used to form crystals, but their directionality is not controlled. After cooling, the silicon is cut into layers and processed according to a special algorithm.

Polycrystalline panels do not require constant orientation towards the sun, so the roofs of houses and industrial buildings are actively used for their placement.

During the day, with light clouds, the advantages of solar panels made of amorphous silicon will not be noticeable; their advantages are revealed only under dense clouds or in the shade

The advantages of solar cells with multidirectional crystals include:

High efficiency in diffuse light conditions.
Possibility of permanent fastening on the roofs of buildings.
Lower cost compared to monocrystalline panels.
The drop in efficiency after 20 years of operation is only 15-20%.

Polycrystalline panels also have disadvantages:

Reduced efficiency with a value of 12-18%.
Requires more installation space per unit of power compared to monocrystalline counterparts.

Polycrystalline solar panels are gaining an increasing market share among other silicon batteries. This is ensured by wide potential opportunities for reducing the cost of their production. The efficiency of such panels also increases every year, rapidly approaching 20% for mass-produced products.

Amorphous silicon solar panels

The mechanism for producing solar panels from amorphous silicon is fundamentally different from the production of crystalline photovoltaic cells. Here it is not a pure non-metal that is used, but its hydride, the hot vapors of which are deposited on the substrate. As a result of this technology, classical crystals are not formed, and production costs are sharply reduced.

Deposited amorphous silicon solar cells can be mounted on either a flexible polymer substrate or a rigid glass sheet

On this moment There have already been three generations of amorphous silicon panels, each of which has noticeably increased efficiency. If the first photovoltaic modules had an efficiency of 4-5%, now second-generation models with an efficiency of 8-9% are widely sold on the market. The latest amorphous panels have an efficiency of up to 12% and are already starting to appear on sale, but they are still quite expensive.

Due to the features of this production technology, it is possible to create a layer of silicon on both a rigid and flexible substrate. Because of this, amorphous silicon modules are actively used in flexible thin-film solar modules. But options with an elastic backing are much more expensive.

The physicochemical structure of amorphous silicon allows maximum absorption of photons of weak scattered light to generate electricity. Therefore, such panels are convenient for use in northern regions with large free areas. The efficiency of batteries based on amorphous silicon does not decrease even at high temperatures, although they are inferior in this parameter to gallium arsenide panels.

At the same equipment cost, silicon hydride solar panels show greater performance than their mono- and polycrystalline counterparts

To summarize, we can point out the following advantages of amorphous solar panels:

Possibility of producing flexible and thin panels.
High efficiency in diffused light.
Installation of batteries on any architectural forms.
Stable operation at high temperatures.
Simplicity and reliability of design. Such panels practically do not break.
Less drop in performance when the surface is dusty than with crystalline analogues

The service life of such photovoltaic cells, starting from the second generation, is 20-25 years with a power drop of 15-20%. The only disadvantages of amorphous silicon panels include the need for larger areas to accommodate equipment of the required power.

Overview of silicon-free devices

Some solar panels, made using rare and expensive metals, have an efficiency of more than 30%. They are several times more expensive than their silicon counterparts, but still occupy a high-tech trading niche due to their special characteristics.

Rare metal solar panels

There are several types of rare metal solar panels, and not all of them are more efficient than monocrystalline silicon modules. However, the ability to operate in extreme conditions allows manufacturers of such solar panels to produce competitive products and conduct further research.

Cadmium telluride panels are actively used for cladding buildings in equatorial and Arabian countries, where their surface heats up to 70-80 degrees during the day

The main alloys used to make photovoltaic cells are cadmium telluride (CdTe), indium copper gallium selenide (CIGS) and copper indium selenide (CIS). Cadmium is a toxic metal, and indium, gallium and tellurium are quite rare and expensive, so mass production of solar panels based on them is even theoretically impossible.

The efficiency of such panels is at the level of 25-35%, although in exceptional cases it can reach up to 40%. Previously, they were used mainly in the space industry, but now a new promising direction has emerged.

Due to the stable operation of photocells made of rare metals at temperatures of 130-150°C, they are used in solar thermal power plants. In this case, the sun's rays from tens or hundreds of mirrors are concentrated on a small panel, which simultaneously generates electricity and ensures the transfer of thermal energy to a water heat exchanger.

As a result of heating the water, steam is formed, which causes the turbine to rotate and generate electricity. In this way, solar energy is converted into electrical energy simultaneously in two ways with maximum efficiency.

Polymer and organic analogues

Photovoltaic modules based on organic and polymer compounds began to be developed only in the last decade, but researchers have already made significant progress. The greatest progress is demonstrated by the European company Heliatek, which has already equipped several high-rise buildings with organic solar panels. The thickness of its HeliaFilm-type roll film structure is only 1 mm.

In the production of polymer panels, substances such as carbon fullerenes, copper phthalocyanine, polyphenylene and others are used. The efficiency of such photovoltaic cells already reaches 14-15%, and the production cost is several times less than crystalline solar panels.

The issue of degradation time of the organic working layer is acute. So far, it is not possible to reliably confirm the level of its efficiency after several years of operation.

The advantages of organic solar panels are:

possibility of environmentally safe disposal;
low cost of production;
flexible design.

The disadvantages of such photocells include relatively low efficiency and lack of reliable information about the periods of stable operation of the panels. It is possible that in 5-10 years all the disadvantages of organic solar cells will disappear, and they will become serious competitors for silicon wafers.

Which solar panel to choose?

The choice of solar panels for country houses at a latitude of 45-60 ° is not difficult. There are only two options worth considering here: polycrystalline and monocrystalline silicon panels. If there is a shortage of space, it is better to give preference to more efficient models with one-sided crystal orientation; if the area is unlimited, it is recommended to purchase polycrystalline batteries.

You shouldn’t rely on the forecasts of analytical companies for the development of the solar panel market, because the best examples of them may not have been invented yet

Select a specific manufacturer, required power and optional equipment It is better with the participation of managers of companies involved in the sale and installation of such equipment. You should know that the quality and price of photovoltaic modules are largest manufacturers differ little.

It should be taken into account that when ordering a set of turnkey equipment, the cost of the solar panels themselves will be only 30-40% of total amount. The payback period for such projects is 5-10 years, and depends on the level of energy consumption and the possibility of selling excess electricity to the city grid.

Conclusions and useful video on the topic

The presented videos show the operation of various solar panels in real conditions. They will also help you understand the issues of choosing related equipment.

Rules for choosing solar panels and related equipment:

Types of solar panels:

Testing of monocrystalline and polycrystalline panels:

For the population and small industrial facilities real alternative crystalline silicon panels are not yet available. But the pace of development of new types of solar panels allows us to hope that in the coming decades, solar energy will become the main source of electricity in many country houses and dachas.

Constantly mastering new frontiers, solar energy is moving forward, raising the efficiency value to new levels. It's no secret that the performance they deliver cannot compete with established energy sources. Blame it all low performance existing panels.

Impact of various factors on performance

Increasing the efficiency is a headache for all researchers working in this direction. Today the efficiency similar devices is in the range from 15 to 25%. The percentage is very low. Solar batteries are an extremely demanding device, the stable operation of which depends on many reasons.

The main factors that can influence performance in two ways include:

Solar cell base material. The weakest in this regard are polycrystalline solar cells, which have an efficiency of up to 15%. Modules based on indium-gallium or cadmium-tellurium, having up to 20% productivity, can be considered promising.
Orientation of the solar flux receiver. Ideally, solar panels with their working surface should be facing the sun at right angles. They should remain in this position for as long as possible. To increase duration correct positioning modules in the solar field, more expensive analogues have in their arsenal a sun tracking device that rotates the batteries following the movement of the luminary.
Overheating of installations. Elevated temperatures have a negative impact on power generation, so during installation it is necessary to ensure adequate ventilation and cooling of the panels. This is achieved by installing a ventilated gap between the panel and the installation surface.
A shadow cast by any object can significantly spoil the efficiency of the entire system.

By fulfilling all the requirements and, if possible, installing the panels in the desired position, you can obtain solar panels with high efficiency. Precisely high, not maximum. The fact is that the calculated, or theoretical efficiency, is a value derived in laboratory conditions, with average parameters for the duration of daylight hours and the number of cloudy days.

In practice, of course, the percentage of beneficial effects will be lower.

When choosing solar panels for your home, it is better to focus on the lower limit of performance rather than the upper limit. Having thus chosen solar modules and all the components required for operation, you can be sure that the installed installation has sufficient power. By choosing the lower limit of performance in the calculations, you can save on the purchase of additional panels, which are purchased for reinsurance in case of a lack of power.

Encouraging development prospects

Today, the absolute record for efficiency in solar energy belongs to American developers and is 42.8%. This value is 2% higher than the previous record in 2010. Record number energy was achieved by improving the solar cell made of crystalline silicon. The uniqueness of such a study is the fact that all measurements were carried out exclusively under working conditions, that is, not in laboratory and greenhouse premises, but in real locations of the proposed installation.

Behind the scenes of the same technical laboratories, work continues to increase the latest record. The next goal of the developers is the efficiency limit solar modules at 50%. Every day, humanity is getting closer and closer to the moment when solar energy will completely replace the harmful and expensive energy sources currently used, and will become on a par with such giants as hydroelectric power plants.

IN Lately Solar energy is developing at such a rapid pace

Recently, solar energy has been developing at such a rapid pace that in 10 years the share solar electricity in global annual electricity generation increased from 0.02% in 2006 to almost one percent in 2016.

Dam Solar Park is the largest solar power plant in the world. Power 850 megawatts.

The main material for solar power plants is silicon, the reserves of which on Earth are practically inexhaustible. One problem is that the efficiency of silicon solar cells leaves much to be desired. The most efficient solar panels have an efficiency of no more than 23%. A average efficiency ranges from 16% to 18%. Therefore, researchers around the world involved in the field of solar photovoltaics are working to free solar photoconverters from the image of a supplier of expensive electricity.

A real struggle has unfolded to create a solar supercell. The main criteria are high efficiency and low cost. The National Renewable Energy Laboratory (NREL) in the USA even periodically issues a newsletter reflecting the interim results of this struggle. And each episode shows the winners and losers, outsiders and upstarts who accidentally got involved in this race.

Leader: solar multilayer cell

These helium converters resemble a sandwich of different materials, including perovskite, silicon and thin films. In this case, each layer absorbs light only of a certain wavelength. As a result, these multilayer helium cells, with an equal working surface area, produce significantly more energy than others.

The record-breaking efficiency of multilayer photoconverters was achieved at the end of 2014 by a joint German-French research team led by Dr. Frank Dimroth at the Fraunhofer Institute for Systems solar energy. An efficiency of 46% was achieved. This fantastic efficiency value was confirmed by an independent study at NMIJ/AIST - the largest metrology center in Japan.

Multilayer solar cell. Efficiency – 46%

These cells are made up of four layers and a lens that concentrates sunlight onto them. The disadvantages include the presence of germanium in the structure of the substrate, which slightly increases the cost of the solar module. But all the shortcomings of multilayer cells can ultimately be eliminated, and researchers are confident that in the very near future their development will leave the walls of laboratories and enter the big world.

Rookie of the Year - Perovskite

Quite unexpectedly, a newcomer intervened in the race of leaders - perovskite. Perovskite is the general name for all materials that have a certain cubic crystal structure. Although perovskites have been known for a long time, research into solar cells made from these materials only began between 2006 and 2008. Initial results were disappointing: the efficiency of perovskite photoconverters did not exceed 2%. At the same time, calculations showed that this figure could be an order of magnitude higher. Indeed, after a series of successful experiments, Korean researchers in March 2016 received a confirmed effectiveness of 22%, which in itself became a sensation.

Perovskite solar cell

The advantage of perovskite cells is that they are more convenient to work with and easier to produce than similar silicon cells. With mass production of perovskite photoconverters, the price of one watt of electricity could reach $0.10. But experts believe that as long as perovskite helium cells reach maximum efficiency and begin to be produced in industrial quantities, the cost of a “silicon” watt of electricity can be significantly reduced and reach the same level of $0.10.

Experimental: quantum dots and organic solar cells

This type of solar photoconverter is still at an early stage of development and cannot yet be considered as a serious competitor to existing helium cells. However, the developer, the University of Toronto, claims that according to theoretical calculations, the efficiency of solar cells based on nanoparticles - quantum dots - will be above 40%. The essence of the invention of Canadian scientists is that nanoparticles - quantum dots - can absorb light in different spectral ranges. By changing the size of these quantum dots, it will be possible to select the optimal operating range of the photoconverter.

Solar cell based on quantum dots

And considering that this nanolayer can be applied by spraying onto any, including transparent, substrate, promising prospects are visible in the practical application of this discovery. And although today in laboratories when working with quantum dots an efficiency indicator of only 11.5% has been achieved; no one doubts the prospects of this direction. And the work continues.

Solar Window – new solar cells with 50% efficiency

The Solar Window company from Maryland (USA) has introduced a revolutionary “solar glass” technology that radically changes traditional ideas about solar panels.

Previously, there were reports about transparent helium technologies, as well as that this company promises to significantly increase the efficiency of solar modules. And, as shown latest events, these were not just promises, but 50% efficiency - no longer just theoretical delights of the company's researchers. While other manufacturers are just entering the market with more modest results, Solar Window has already presented its truly revolutionary high-tech developments in the field of helium photovoltaics.

These developments pave the way for the production of transparent solar cells, which have significantly higher efficiency compared to traditional ones. But this is not the only advantage of the new solar modules from Maryland. New helium cells can be easily attached to any transparent surfaces (for example, windows), can work in the shade or when artificial lighting. Due to their low cost, investments in equipping a building with such modules can pay for themselves within a year. By comparison, the payback period for traditional solar panels ranges from five to ten years, which is a huge difference.

Solar cells from the Solar Window company

Solar Window Company has announced some details new technology obtaining solar cells with such high efficiency. Of course, the main know how was left out of the equation. All helium cells are made primarily of organic material. The layers of elements consist of transparent conductors, carbon, hydrogen, nitrogen and oxygen. According to the company, the production of these solar modules is so environmentally friendly that it has 12 times less environmental impact than the production of traditional helium modules. Over the next 28 months, the first transparent solar panels will be installed in some buildings, schools, offices and skyscrapers.

If we talk about the prospects for the development of helium photovoltaics, it is very likely that traditional silicon solar cells can become a thing of the past, giving way to highly efficient, lightweight, multifunctional elements that open up the broadest horizons for helium energy. published

What affects the efficiency and performance of solar panels?

Today there is a lot of talk around such a thing as the efficiency of solar systems. This is one of the key criteria when assessing the efficiency of solar panels. Increasing this indicator is the main task towards reducing the costs of converting solar energy and expanding the use of solar systems. The low efficiency of solar panels is their main disadvantage. Square meter modern solar cells provide the generation of 15-20 percent of the power of solar radiation falling on it. And this is under the most favorable operating conditions. As a result, the installation of many solar panels is required to provide the necessary energy supply. large area. We will try to understand in this article how effective such equipment is and what its efficiency depends on. We’ll also talk about the service life and payback of solar panels.

The functioning of solar panels is based on the properties of semiconductor elements. Sunlight falling on photovoltaic panels by photons knocks out electrons from the outer orbit of atoms. The resulting large number of electrons provides an electric current in a closed circuit. One or two panels are not enough for normal power. Therefore, several pieces are combined into solar panels. To obtain the required voltage and power, they are connected in parallel and in series. Larger number photocells provide a large area for absorbing solar energy and produce more power.

Now directly about the efficiency itself. This value is calculated by dividing the power of electricity by the power of solar energy hitting the panel. For modern solar batteries, this value lies in the range of 12-25 percent (in practice, no higher than 15%). Theoretically, it is possible to increase the efficiency to 80-85 percent. This difference exists due to the materials used to make the panels. It is based on silicon, which does not absorb ultraviolet light, but only the infrared spectrum. It turns out that the energy of ultraviolet radiation is wasted.

One of the directions for increasing efficiency is the creation of multilayer panels. Such structures consist of a set of materials arranged in layers. The selection of materials is carried out so that quanta of different energies are captured. A layer with one material absorbs one type of energy, with a second – another, and so on. As a result, it is possible to create solar cells with high efficiency. Theoretically, such multilayer panels can provide efficiency of up to 87 percent. But this is in theory, but in practice the manufacture of such modules is problematic. In addition, they turn out to be very expensive.

The efficiency of solar systems is also affected by the type of silicon used in solar cells. Depending on the production of the silicon atom, they can be divided into 3 types:

Monocrystalline;
Polycrystalline;
Amorphous silicon panels.

Photocells made of monocrystalline silicon have an efficiency of 10-15 percent. They are the most effective and have a higher cost than others. Polycrystalline silicon models have the cheapest watt of electricity. Much depends on the purity of the materials, and in some cases polycrystalline elements may be more effective than single crystals.

There are also photocells made of amorphous silicon, on the basis of which thin-film flexible panels are made. Their production is simpler and the price is lower. But the efficiency is much lower and amounts to 5-6 percent. Amorphous silicon elements lose their characteristics over time. To increase their productivity, particles of selenium, copper, gallium, and indium are added.

What determines the efficiency of solar panels?

The efficiency of solar panels is influenced by several factors:

Temperature;
Angle of incidence of sunlight;
Surface cleanliness;
Lack of shadow;
Weather.

Ideally, the angle of incidence of sunlight on the surface of the photocell should be straight. All other things being equal, in this case there will be maximum efficiency. In some models, a sun tracking system is installed in solar panels to increase efficiency. It automatically changes the angle of the panels depending on the position of the sun. But this pleasure is not cheap and therefore rare.

During operation, photocells heat up, and this negatively affects their efficiency. To avoid losses during energy conversion, space should be left for the panels and the surface where they are fixed. Then a flow of air will pass under them and cool them.

The panels must be washed and wiped several times a year. After all, the efficiency of photovoltaic panels directly depends on the incident light, and therefore on the cleanliness of the surface. If there is contamination on the surface, the efficiency of solar panels will decrease.

It is important to install the batteries correctly. This means that no shadow should fall on them. Otherwise, the efficiency of the system as a whole will be greatly reduced. It is highly advisable to install photocells on the south side.

As for the weather, a lot also depends on it. The closer your region is to the equator, the greater the density of solar radiation hitting the panels. In our region in winter, efficiency can drop by 2-8 times. The reasons are both a decrease in sunny days and snow falling on the panels.

Service life and payback of solar panels

There are no moving mechanical parts in solar systems, which makes them durable and reliable. The service life of such batteries is 25 years or longer. If they are properly operated and maintained, they can last 50 years. In addition, there are no serious breakdowns in them and the owner is only required to periodically clean the solar cells from dirt, snow, etc. This is required to increase the efficiency and efficiency of the solar system. Long service life often becomes the determining factor when deciding whether or not to buy solar panels. After all, after the payback period has passed, the electricity from them will be free.

And the payback period is significantly shorter than the service life. But many are stopped by the initial cost of batteries. Coupled with the low efficiency, many people have doubts about the profitability of purchasing solar systems. Therefore, the decision here must be made taking into account the weather and climate in your region, conditions of use, etc.

The payback period is influenced by the following factors:

Type of photocells and equipment. Payback is influenced by both the efficiency value and the initial cost of solar cells;
Region. The higher the intensity of sunlight in your area, the shorter the payback period;
Price of equipment and installation;
The price of electricity in your region.

The average payback period by region is:

Southern Europe ─ up to 2 years;
Central Europe – up to 3.5 years;
Russia ─ in most regions up to 5 years.

Efficiency of solar collectors for collecting heat and batteries for receiving electrical energy is constantly increasing. True, not as fast as we would like. Industry specialists are working to increase the efficiency and reduce the cost of photovoltaic cells. As a result, all this should lead to a reduction in the payback period and widespread use of solar panels.