The general trend in solar modules is towards high-performance monocrystalline solar modules with N-type cells in half-cut technology. The rated power here is usually 350Watt peak and more. Especially in the project business more and more bifacial modules are used, especially in combination with N-Type doped solar cells, the transparent photovoltaic modules can fully play out their advantages and a maximum of power can be obtained from the module. The contacting of the cells also goes in the direction of 9BB and MBB. While in 2018/2019 polycrystalline modules were still occasionally installed in photovoltaic systems, modules with this cell technology are almost no longer installed or if so then mostly only in the 144 cell variant with an output of at least 400 watts peak.

The question must be considered more differentiated because there are different purposes for solar modules and thus also requirements. As an investor of a photovoltaic system (large projects in the commercial sector) you are usually looking for a solar panel that offers the best LCOE. However, if you install a solar system on your private roof and you are limited in the available area, the best solar module is one with a high nominal power and an attractive appearance the better solution. The risk profile of the investor also plays a role in the choice of the best solar module, because the manufacturers advertise with different performance and product guarantees for the favor of customers.

Unfortunately, module and cell production in Europe is no longer profitable and well-known manufacturers such as Q-Cells and Solarworld have either had to close or have been sold. Even well-known manufacturers in the premium segment source their cells from Asia, which incidentally also affects a large part of the BOM (Bill of Material).

As in other industries, there is now a wide choice of manufacturers of solar modules. With an investment that can quickly run into the tens of thousands, it is all the more important to choose the right manufacturer.

The 10 best solar module manufacturers that we can recommend without hesitation in 2023 are:

The manufacturers listed here are among the leaders in the world and have been selected for their excellent quality, long experience, technological development and price-performance ratio. As an independent and leading marketplace for photovoltaics in Europe, we have more than 10 years of experience in the business.

If you want to install the solar modules yourself, you can buy them in various online stores. However, it is advisable to visit a solar installer to get the appropriate quotes. A solar installer can also carry out the complete planning, installation and handover of the connected solar system. Installing companies also have the possibility to make their purchase at one of the numerous distributors. The largest distributors for solar modules in Germany are IBC Solar, Krannich Solar, Baywa Solar. In the project business from 500KW, the solar modules are usually purchased directly from the manufacturer, or via a solar platform. This offers the advantage of easy comparability and cost advantages in purchasing.

The price of a module depends among other things on: Power class, cell technology, manufacturing costs, distribution costs, markup of the manufacturer, markup of the distributor. The price of a solar module is given in EUR per Wp for better comparability in professional circles. While the price in 2022 was still around EUR 0.32 per watt, it will be only EUR 0.25 per watt in 2023. A module with 120 mono cells and a nominal power of 420 watts thus costs 105 EUR. However, depending on the size of the photovoltaic system, the module price only accounts for a small part of the total costs.

Wp stands for Watt Peak or the power of the module under STC 1000. The power of a solar module is measured in watts. However, this value varies greatly depending on the cells used, temperature, light irradiation and other factors. In order to evaluate and compare the performance of solar modules and their efficiency, standard test conditions have been introduced by the industry. The results of the performance of a solar module are then shown with other parameters on the data sheet of the solar panel. Here you will also find the Watt peak power, i.e. the power of the module at 1000W irradiation. Likewise, in production, each module is measured in a "flasher" for its power and assigned to the serial number. Thus, one can assign performance data to each module with the help of a flash report. In addition, Wp is often used in the calculation and pricing of photovoltaic modules. Here you can find information such as 0.24 EUR/Wp which allows you to determine and compare the relative price per watt of a module.

Basically, a solar module can only generate electricity when light hits its surface. The principle of photovoltaics is a direct conversion of light into electrical energy, whereby an electrical voltage is generated between electrodes.
A module such as the Sunpower Maxeon 3 with dimensions of 1690 x 1046 and an output of 400 watts can therefore deliver a current of 6.08 A (Impp) at a voltage of 65.8 V (Umpp) under STC 1000. This is equivalent to 400 watts. However, how much current is generated in practice depends on many other factors, the most important being solar radiation, orientation, azimuth, temperature and system configuration. If the area available for the installation of the solar system is limited, it is advisable to choose the most efficient solar module, i.e. a photovoltaic module that provides the highest possible power in relation to the area (LxW).

We have often been asked by investors whether a monocrystalline or polycrystalline module is better. We do not want to give a general answer, but due to the technological development of the last 2 years, poly modules are hardly used in solar projects. Monocrystalline modules have become more efficient and above all cheaper in recent years. So that in 85% of the plants today monocrystalline modules are installed. We do not expect a comeback of poly modules and assume that the market share of mono modules will increase to 99% by 2025.

In order to operate a solar module or several solar modules in a solar system, you always need an inverter when you need alternating current. Alternating current is for example the household current with 230V that we know. In this way you can connect different electrical consumers (TV, washing machine, etc.). The inverter is needed to convert the direct current (DC) of the generator (photovoltaic module) into alternating current (AC). The power of the inverter must be put in relation to the power of the solar modules. An optimal design of a photovoltaic system and the related detailed selection of the appropriate inverter requires basic practical and theoretical knowledge. For planning and design, modern programs are used that take into account the parameters of the individual components and other factors such as the location.

To be able to store the electricity generated by a photovoltaic system, an accumulator or memory is needed. In most cases, a Li-Ion battery is used to store the electricity generated during the hours of sunshine and to use it when it is needed. This can be days when the sun is not shining, during the night or during the day, when the power of the solar system alone is not enough. The combination of solar modules with solar storage is becoming more and more popular and most systems in the residential segment are already equipped with electricity storage. With the currently falling prices for solar storage and the trend towards electromobility, we expect the trend towards electricity storage to continue. Notable manufacturers here are BYD, LG, Solax. The performance of solar storage systems can usually be expanded in a modular fashion, so that one can start with a small storage system and upgrade as needed.

Frameless modules, often referred to as "frameless", play only a minor role in the photovoltaic industry. They are still a niche product and are always used when there are special aesthetic requirements. Modules without a frame usually have a lower stability than framed modules. To protect the modules against mechanical stress (snow, wind/suction), the modules are often produced as glass/glass modules. This makes them relatively heavy, but offers good mechanical stability and quality.

The more light hits a solar module, the higher its output will be. If the sun is covered by clouds, the performance of the solar module will also decrease. However, this power loss is not as high as one might think because light is still present and the light waves are not completely refracted by the cloud cover. The effect of cloud cover on the performance of a solar module can best be observed in practice. More and more frequently, STC 800 values are also listed on the data sheets. There you can see quite well how the irradiation value affects the performance of the solar module (of course everything only under laboratory conditions).

The selection of solar modules was still you large as now. The size of the solar dolus is usually based on the size of the cell used and the number of cells. There are particularly small solar modules with a nominal power of 5 watts, these are used when small consumers such as signal lights and measuring instruments must be operated. The dimensions of such a module are 255 x 255 x 35 mm. But then, of course, there are also much larger modules that are used for grid-feeding photovoltaic systems. A 144 cell polycrystalline module like the CS3W-405 Hiku from Canadian Solar has the dimensions 2108 x 1048 x 40 mm.

Depending on the module type and local conditions, there are different mounting options. Basically, the installation of solar modules should be done professionally in any case. For solar modules that are intended for feeding into the grid, there are installation instructions from the manufacturers. These instructions state how the solar module is to be fixed in order to ensure the required safety. Almost all modules can be mounted horizontally and/or vertically. The different requirements for the clamping must be observed, otherwise neither the manufacturer nor the insurance company will settle the claim. Depending on the region, the requirements for mounting are different. Regions such as the Alps have higher requirements for the mechanical load (pressure) due to large snow masses. In coastal regions, on the other hand, the suction load due to wind plays an important role. When installing the solar system on a roof, the calculation of the statics must be observed and the exposure (building height, surroundings) must also be taken into account. Depending on the roof type and roof covering, a choice can be made between different mounting systems.

You are afraid that someone will steal your solar panel and you would like to protect yourself against theft. We can reassure you, because such incidents rarely occur. The reason for this is simply the module price. While in 2011 you still paid 2.30 EUR per watt, in 2023 it will only be 0.23 EUR per watt. Modules have therefore become much cheaper and theft is no longer worthwhile. To secure the photovoltaic modules of grid-feeding solar power plants, a motion detector with a spotlight, night vision cameras and fencing of the area is suitable.

If a 400W solar module delivers only 350W at full solar irradiation, some people immediately assume a defect. Far from it, because all too often people forget that the manufacturer's specifications refer to the STC 1000 (standard test conditions). Here, the performance of the solar module is measured under optimal irradiation angle, an irradiation of 1,000 watts and an ambient temperature of 25°C. In practice, however, such laboratory conditions do not occur. In practice, however, such laboratory conditions occur only very rarely. Therefore, it is normal that your solar module does not generate the full power as specified in the data sheet. It is best to measure the power of your module under optimal irradiation angle and then consider the ambient temperature. To do this, consult the temperature coefficient for STC 800. You should then get an approximate value. It is best to measure the current directly at the module to exclude other factors in the solar system as a possible source of error.

For photovoltaic modules, various parameters such as quality, technology, reputation of the manufacturer, price, availability and performance characteristics play an important role.

The 3 most important performance characteristics:

The rated power of a module is determined under standard test conditions. It is then stated in watts peak. The power range in Q2 - 2023 is from 400 watts to 650 watts. However, we expect that modules in a power class of 650 watts and more will be available in distribution in Q4-2023 at the latest. The highest power classes of the respective series (60 cell - monofacial, 120 cell - monofacial, 66 cell - monofacial, 54 cell - monofacial) are usually somewhat more expensive. Current monocrystalline modules with halfcut technology (120 cells or 144 cells) which are also available in distribution have an output of 400 watts to 570 watts.

However, a high output measured in watts does not necessarily mean that the module is also efficient and has a high efficiency. Module efficiency is the ratio of the module's power output under STC to the area of the solar module. Generally, modules with higher efficiency are more expensive because more power can be produced per area with an efficient module. A module with an efficiency greater than 21% is commonly dubbed a high efficiency module. However, we don't have much use for the term. In any case, the trend is towards modules with a higher efficiency, in this way leading manufacturers try to distance themselves from the not so well-known and technologically advanced companies. A low price per watt is just not everything.

This coefficient can be used to determine the performance of a solar module under certain temperatures. While a cell temperature of 25°C prevails in the test conditions, this can be many times higher in practice. Cell temperatures around 60^C are not uncommon in summer. As cell temperature increases, the performance of a solar module decreases. Therefore it is important to select a solar module with a temperature coefficient as low as possible. A temperature coefficient of -0.36% /°C (A) is worse than a temperature coefficient of -0.32%/°C (B). To illustrate this, we compare the two temperature coefficients (Pmax) at 55°C cell temperature:

Power module A with -0.36% /°C: 400W at 25°C and 356.8W at 55°C (loss: 43.2W)
Power module B with -0.28%/°C: 400W at 25°C and 366.4W at 55°C (loss: 33.6W)
Module B thus produces 2.7% more power under real conditions.

Manufacturers of solar modules offer their customers a product warranty and performance guarantee. The product warranty is usually 12 - 15 years. The performance warranty is usually 25 years. Since photovoltaic modules lose performance over time, the performance guarantee is a warranty where after a certain time the user is guaranteed a certain performance. The exact terms of this can be found in the manufacturer's warranty policy. A performance guarantee of 30 years sounds great for the customer. However, how much is this worth if the manufacturer is already overindebted at the time the warranty is issued and its continued existence is in jeopardy? Especially with Chinese companies, the evaluation of guarantees is difficult. Especially if they are smaller manufacturers.

The mechanical load capacity is tested for almost all manufacturers by corresponding test companies such as TÜV or SGC and certified to the manufacturer for the associated product group with an IEC certificate. In recent years, the following standards have actually become established:
Maximum static load on the front side: 5400Pa
Maximum static load on the back side: 2400Pa

The static load on the front side is relevant for snow loads, while the wind load (suction) is relevant for the back side. Some regions (high altitudes, coastal regions) are particularly exposed and may therefore have special requirements. Decisive for the compliance of the modules with these values in practice is the professional installation. In particular, the clamping area, since the static maximum load capacity of a solar module can be greatly changed by different clamping areas.