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Efficiency of solar panels. Types of solar panels, their efficiency. Nano solar cells

Recently, solar energy has been developing at such a rapid pace.

Recently, solar energy has been developing at such a rapid pace that in 10 years, the share of solar electricity in global annual electricity generation has 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%. And the average efficiency rate 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, the outsiders and the 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 Solar Energy Systems. 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 laboratories have achieved an efficiency rate of only 11.5% when working with quantum dots, 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 recent events have shown, these were not just promises, but 50% efficiency - no longer just the 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), and can work in the shade or under artificial light. 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

The Solar Window company announced some details of the new technology for producing solar panels 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

Solar panels are a unique system that allows you to convert solar rays into electrical and thermal energy. The growing demand for solar products today is determined by their quick payback, durability, and availability of coolant. But what voltage can solar panels produce? Read the article about how effective solar systems are and what their efficiency depends on.

High efficiency solar panels: types of converters

The efficiency of solar batteries is a value that is equal to the ratio of the power of electricity to the power of solar rays incident on the panel of the device. Modern solar cells have an efficiency ranging from 10 to 45%. This large difference is due to differences between the materials used and the design of the battery plates.

So, solar panel plates can be:

  • Thin film;
  • Multi-junction.

The latter type of solar panels, today, are the most expensive, but also the most productive. This is due to the fact that each junction in the plate absorbs waves of a certain length. Thus, the device covers the entire spectrum of sunlight. The maximum efficiency of batteries with multijunction panels obtained in laboratory conditions is 43.5%.

Energy experts say with confidence that in a few years this figure will increase to 50%. The efficiency of thin-film plates depends, to a large extent, on the material they are made of.

Thus, thin-film solar batteries are divided into the following types:

  • Silicon;
  • Cadmium.

The most popular solar batteries that can be used for domestic purposes are those with silicon film wafers. The volume of such devices on the market is 80%. Their efficiency is quite low - only 10%, but they are affordable and reliable. The efficiency index is several percent higher for cadmium plates. Films with particles of selenide, copper, indium and gallium have a higher efficiency, which is equal to 15%.

What determines the efficiency of solar panels?

The efficiency of photoelectric converters is influenced by many factors. So, as noted above, the amount of energy generated depends on the structure of the converter panel and the material of their manufacture.


In addition, the efficiency of solar inverters depends on:

  • Forces of solar radiation. Thus, with a decrease in solar activity, the power of solar installations decreases. In order for the batteries to provide the consumer with energy at night, they are supplied with special batteries.
  • Air temperatures. Thus, solar panels with cooling devices are more productive: heating the panels negatively affects their ability to convert energy into current. So, in frosty, clear weather, the efficiency of solar batteries is higher than in sunny and hot weather.
  • The angle of inclination of the device and the incidence of sunlight. To ensure maximum efficiency, the solar panel should be aimed directly at the sun's radiation. The most effective models are those whose inclination level can be changed relative to the location of the Sun.
  • Weather conditions. In practice, it has been noted that in areas with cloudy, rainy weather, the efficiency of solar converters is much lower than in sunny regions.

In addition, the efficiency of solar converters is also affected by their level of cleanliness. In order for the device to work productively, its plates must consume as much solar radiation as possible. This can only be done if the devices are clean.

The accumulation of snow, dust and dirt on the screen can reduce the efficiency of the device by 7%.

It is recommended to wash screens 1-4 times a year, depending on the degree of contamination. In this case, you can use a hose with a nozzle for cleaning. Technical inspection of converter elements should be carried out every 3-4 months.

Solar power per square meter

As noted above, on average, one square meter of photovoltaic converters provides the generation of 13-18% of the power of the sun's rays falling on it. That is, under the most favorable conditions, you can get 130-180 W per square meter of solar panels.

The power of solar systems can be increased by increasing the panels and increasing the area of ​​photovoltaic converters.

You can also get more power by installing panels with higher efficiency. However, the rather low (in comparison, for example, with induction converters) efficiency of available solar cells is the main obstacle to their widespread use. Increasing the power and efficiency of solar systems is the primary task of modern energy.

The most efficient solar panels: rating

The most efficient solar converters today are produced by Sharp. Three-layer, high-power, concentrating solar panels have an efficiency of 44.4%. Their cost is incredibly high, so they are used only in the aerospace industry.


The most affordable and effective are modern solar panels from the following companies:

  • Panasonic Eco Solutions;
  • First Solar;
  • MiaSole;
  • JinkoSolar;
  • Trina Solar;
  • Yingli Green;
  • ReneSola;
  • Canadian Solar.

Sun Power produces the most reliable solar inverters with an efficiency of 21.5%. The company's products are absolutely popular in commercial and industrial facilities, second only to devices from Q-Cells.

Efficiency of solar panels (video)

Modern solar panels, as environmentally friendly energy conversion devices with inexhaustible coolant, are gaining increasing popularity. Already today, devices with photoelectric converters are used for household purposes (charging phones, tablets). The efficiency of solar installations is still inferior to alternative methods of energy production. But increasing the efficiency of converters is the primary task of modern energy.

About the solar-powered base station. The caveat was that the payback period for a solar panel power system is 2-3 years. By profession, I am engaged in the installation and commissioning of systems of alternative energy sources and, as I see it, The authors of articles on this topic underestimate the time during which the system fully pays for itself, several times more.

I don’t pretend to be absolutely accurate, but the numbers are not taken out of thin air, but from a specific facility where the team did the installation – the Simferopol production and warehouse complex “Myasko”. The calculations include the main most costly items.

At the time of our work, this plant already had a farm with 300+ panels assembled using a modular system. We added six more circuits of twenty panels. (Circuit - combining a certain number of panels into one energy source, thus dialing the circuit of the voltage required for the inverter).

Dry calculations

Now a little about the numbers, all calculations are carried out with the cost of delivery to Crimea from Germany.


Total:
A truss of 120 panels costs $59,000. These calculations do not yet include wages for the designer, engineer and installers. In total, everything will result in a budget tending to $65,000.

Actual power output

Theoretically, under ideal conditions, one panel should produce approximately 220-230 W per hour (in terms of the usual 220 volts). Below are the graphs maintained by the control unit in the inverter; they can be monitored remotely.

sunny day:

Partly cloudy:

Monthly chart:

In the last graph, it should be taken into account that for two days the system was turned off for a while, and the first three days of the month and the last two are missing.

In a consistently sunny summer month, with long daylight hours, such a farm will produce a maximum of 4500-4700 kWh. Knowing these numbers, you can calculate the profitability of the system, taking into account electricity tariffs.

It should be taken into account that the farm was assembled without batteries; their presence would increase the total cost of the system and, accordingly, the payback time.

Thus, I can’t achieve a payback period of 2-3 years. 10 years is a more or less realistic period.

It's time to talk about how effective solar energy is in the Moscow region. For a whole year I collected statistics on solar energy production from two 100-watt solar panels installed on the roof of a country house and connected to the network using a grid inverter. I already wrote about this a year ago. And now it's time to take stock.

Now you will learn something that solar panel sellers will never tell you.

Exactly a year ago, in October 2015, as an experiment, I decided to join the ranks of the “greens” who are saving our planet from premature death, and purchased solar panels with a maximum power of 200 watts and a grid inverter designed for a maximum of 300 (500) watts of generated power . In the photo you can see the structure of the polycrystalline 200 watt panel, but a couple of days after purchase it became clear that in a single configuration it was too low voltage, not enough for the correct operation of my grid inverter.

So I had to change it to two 100-watt monocrystalline panels. In theory they should be a little more efficient, but in reality they are just more expensive. These are high quality panels from the Russian brand Sunways. I paid 14,800 rubles for two panels.

The second cost item is a Chinese-made grid inverter. The manufacturer did not identify itself in any way, but the device was made with high quality, and an opening showed that the internal components are designed for a power of up to 500 watts (instead of 300 written on the case). Such a grid costs only 5,000 rubles. The grid is an ingenious device. On the one hand, + and - from the solar panels are connected to it, and on the other hand, it is connected to absolutely any electrical outlet in your home using a regular electrical plug. During operation, the grid adapts to the frequency in the network and begins to “pump” alternating current (converted from direct current) into your 220 volt home network.

The grid operates only when there is voltage in the network and cannot be considered as a backup power source. This is its only drawback. And a huge advantage of a grid inverter is that you basically don’t need batteries. After all, batteries are the weakest link in alternative energy. If the same solar panel is guaranteed to work for more than 25 years (that is, after 25 years it will lose approximately 20% of its performance), then the service life of an ordinary lead-acid battery under similar conditions will be 3-4 years. Gel and AGM batteries will last longer, up to 10 years, but they also cost 5 times more than conventional batteries.

Since I have mains electricity, I don't need any batteries. If you make the system autonomous, then you need to add another 15-20 thousand rubles to the budget for the battery and the controller for it.

Now, as for electricity generation. All energy generated by solar panels enters the network in real time. If there are consumers of this energy in the house, then all of it will be used up, and the meter at the entrance to the house will not “spin”. If the instantaneous generation of electricity exceeds that currently consumed, then all the energy will be transferred back to the network. That is, the counter will “spin” in the opposite direction. But there are nuances here.

Firstly, many modern electronic meters count the current passing through them without taking into account its direction (that is, you will pay for the electricity sent back to the network). And secondly, Russian legislation does not allow private individuals to sell electricity. This is allowed in Europe and that is why every second house there is covered with solar panels, which, combined with high network tariffs, allows you to really save money.

What to do in Russia? Do not install solar panels that can produce more energy than the current daily energy consumption in the house. It is for this reason that I have only two panels with a total power of 200 watts, which, taking into account inverter losses, can supply approximately 160-170 watts to the network. And my house consistently consumes about 130-150 watts per hour around the clock. That is, all the energy generated by solar panels will be guaranteed to be consumed inside the house.

To control the energy produced and consumed, I use Smappee. I already wrote about him last year. It has two current transformers, which allow you to keep track of both the network electricity and the electricity generated by solar panels.

Let's start with theory and move on to practice.

There are many solar power plant calculators on the Internet, so you can take a look at what it is. From my initial data, according to the calculator, it follows that the average annual electricity production of my solar panels will be 0.66 kWh/day, A total output for the year - 239.9 kWh.

This data is for ideal weather conditions and does not take into account losses for converting direct current to alternating current (you are not going to convert your household's power supply to direct voltage?). In reality, the resulting figure can be safely divided by two.

Let’s compare with actual production data for the year:

2015 - 5.84 kWh
October - 2.96 kWh (from October 10)
November - 1.5 kWh
December - 1.38 kWh
2016 - 111.7 kWh
January - 0.75 kWh
February - 5.28 kWh
March - 8.61 kWh
April - 14 kWh
May - 19.74 kWh
June - 19.4 kWh
July - 17.1 kWh
August - 17.53 kWh
September - 7.52 kWh
October - 1.81 kWh (until October 10)

Total: 117.5 kWh

Here is a graph of electricity generation and consumption in a country house over the last 6 months (April-October 2016). It was during April-August that the lion's share (more than 70%) of electrical energy was generated by solar panels. During the remaining months of the year, production was impossible largely due to cloudiness and snow. Well, don’t forget that the efficiency of the grid for converting direct current into alternating current is approximately 60-65%.

Solar panels are installed in almost ideal conditions. The direction is strictly south, there are no tall buildings nearby that cast a shadow, the installation angle relative to the horizon is exactly 45 degrees. This angle will give the maximum average annual electricity production. Of course, it was possible to buy a rotating mechanism with an electric drive and a sun tracking function, but this would increase the budget of the entire installation by almost 2 times, thereby pushing its payback period to infinity.

I have no questions about generating solar energy on sunny days. It fully corresponds to the calculated ones. And even a decrease in production in winter, when the sun does not rise high above the horizon, would not be so critical if not for... cloudiness. Cloudiness is the main enemy of photovoltaics. Here is the hourly output for two days: October 5 and 6, 2016. On October 5 the sun was shining, and on October 6 the sky was covered with lead clouds. Sun, oh! Where are you hiding?

In winter there is another small problem - snow. There is only one way to solve this: install the panels almost vertically. Or manually clear them of snow every day. But snow is nonsense, the main thing is that the sun is shining. Even if it’s low above the horizon.

So, let's calculate the costs:

Grid inverter (300-500 watts) - 5,000 rubles
Monocrystalline solar panel (Grade A - highest quality) 2 pcs, 100 watts each - 14,800 rubles
Wires for connecting solar panels (cross section 6 mm2) - 700 rubles
Total: 20,500 rubles.

Over the past reporting period, 117.5 kWh were generated, at the current daily tariff (5.53 rubles/kWh) this will be 650 rubles.

If we assume that the cost of network tariffs will not change (in fact, they change upward 2 times a year), then I will be able to return my investments in alternative energy only after 32 years!

And if you add batteries, then this whole system will never pay for itself. Therefore, solar energy in the presence of grid electricity can be beneficial only in one case - when our electricity costs the same as in Europe. If 1 kWh of network electricity costs more than 25 rubles, then solar panels will be very profitable.

In the meantime, it is profitable to use solar panels only where there is no network electricity, and its implementation is too expensive. Let's assume that you have his country house, located 3-5 km from the nearest electric line. Moreover, it is high-voltage (that is, you will need to install a transformer), and you have no neighbors (no one to share the costs with). That is, you will have to pay approximately 500,000 rubles to connect to the network, and after that you will also have to pay network tariffs. In this case, it will be more profitable for you to buy solar panels, a controller and batteries for this amount - after all, after putting the system into operation, you will no longer need to pay any more.

In the meantime, it is worth considering photovoltaics exclusively as a hobby.

One of the most common questions that comes up when deciding to install solar panels for personal use is which solar panels are the most efficient? However, this formulation is not entirely correct. First of all, the literal answer to this question does not matter to the average consumer. Let's try to figure out why?

In fact, the important question is not how to choose the most efficient solar panels, but which ones have the best value for money. If you have space on your roof to install ten solar panels and have a choice between "A" solar panels, which are slightly more efficient but twice as expensive as "B" solar panels, then most likely In terms of savings, it is more advisable to choose class “B” panels. In short, the main task is to find out which options are available in a particular situation and analyze the economic impact of each of them.
In any case, if you really want to know the most efficient solar panels (or solar modules), then some of them are listed below, along with the manufacturer and efficiency value:

  • solar panels with 44.4% efficiency from Sharp. Concentrating three-layer solar modules from the world leader in solar cell manufacturers are very complex and are not used in residential or public buildings because they are incredibly expensive. Basically, such solar modules have found application in the space industry, where efficiency with relatively small size and weight is of great importance;
  • solar modules with an efficiency of 37.9% produced by Sharp. These three-layer solar panels are a simpler analogue of the previous ones, with the difference that they do not use special devices to concentrate sunlight onto the module. Accordingly, the price of such panels is lower than the cost of these devices;
  • solar panels with 32.6% efficiency from the Spanish Solar Energy Research Institute (IES) and University (UPM). They are even simpler two-layer modules with a solar concentrator, but their use in residential or public buildings is still too expensive.

There are about a dozen or so other types of solar panels that could go on with this list. Some of them have very high efficiency but are very expensive, while others are quite cheap but have very low efficiency. Of course, some of them are ineffective and expensive at the same time. But, nevertheless, they are of certain research interest. The key, as noted earlier, is to find the optimal balance between cost and effectiveness.
There is an opinion that today much less scientific research is devoted to solar batteries than to photovoltaic cells, which are the basis of solar cell production technology - this is what scientists from many world institutes and universities spend their time on. No one will even try to make a solar battery that will not be sold due to the weak commercial attractiveness of its components - solar modules. Today on the market there are many different types of solar cells (more precisely, solar modules) from a variety of manufacturers. So let's take a look at the leaders in the various categories:

  • Amonix's 36% efficient solar modules hold the overall performance record. However, they are made using concentrating devices and are not used for household purposes;
  • solar modules with an efficiency of 21.5% from the American company Sun Power set a commercial efficiency record. Sun Power SPR-327NE-WHT-D solar modules lead the way in efficiency in field testing. The solar modules that took second and third place in this test were also developed by Sun Power;
  • Thin film solar modules with 17.4% efficiency from Q-Cells hold the record in this category. Thin film solar panels are widely used, but not in residential buildings. Q-Cells is a German company that filed for bankruptcy in 2012 and was later acquired by the Korean company Hanwha;
  • First Solar's 16.1% efficient cadmium-tellurium (CdTe) photovoltaic conversion thin-film solar modules are leaders in their category. Again, solar cells based on such modules are generally not used for domestic purposes, but help the company maintain a high position among solar cell manufacturers. The American company FirstSolar was the leader in the production of solar panels in the American market and took second place in the world ranking last year. Despite the rather low efficiency of 16.1% in this category, First Solar's relatively cheap solar modules are the optimal choice for many industries;
  • The last example to demonstrate that the list of the most efficient solar panels is very long and is not limited to the examples above, we note flexible solar modules with an efficiency of 15.5% from the company MiaSole, a leader in this category. Naturally, for some purposes, not just solar panels are needed, but flexible solar panels. But this is probably not your case...

To summarize, we advise you not to focus on hypothetical and irrelevant advantages when choosing solar panels for your needs. Forget about trying to choose " most efficient solar panels" Look for panels that clearly serve a specific purpose, rather than trying to find solar panels that were designed for NASA satellites.
The chart, compiled by the US National Renewable Energy Laboratory, clearly demonstrates the wide variety of solar cell technologies and each of them's achievements in terms of efficiency.