Solar Panels
Currently, there are dozens of different types of solar panels available from almost as many manufacturers in United Kingdom alone. When the contractors on the market advertise the panels they sell the most, it is sometimes difficult to make an unbiased decision and choose the right one for you.In this article, we will provide an unbiased assessment to help you make your decision.The main criteria we urge you to consider when choosing solar panels are:- Solar panels size (dimensions and power)
- Solar panels price
- Technology
- Warranty
- Appearance
- Country of origin of the panels. How important is it?
Solar module size (dimensions and power)
A very common situation is the limited roof space of a house and the desire (or prospective plan) to install as much solar power as possible to cover not only the current but also the future electricity needs (when planning an electric car or a change of heating method to a heat pump, etc.). Therefore, the first step in the module selection process should be to find the optimal balance between power and dimensions, either by trying to fit as much module capacity as possible on the existing roof area or by leaving an adequate area for expansion.20 panels of the same power output will always produce more electricity than 16 panels of the same power output from the best manufacturer or technology.Please note that you will be offered panels of very different capacities. They can usually range from 300 to 500 watts (Wp) and more. This does not mean that some panels are more efficient than others. Most of the time, the size of the module is what makes the difference. The two most common module size standards are 60-cell (or 120 chopped cells) and 72-cell (144 chopped cells) solar panels. A 60 (120) cell module has an area of about 1.7 square metres, while a 72 (144) cell module has an area of over 2 square metres.The most suitable panel for you is the one with the dimensions that can accommodate the maximum power output. Take note of the width and length of the roof and see which dimensions can accommodate more panels. Although 72 (144) cell panels have mostly been used for large ground-mounted solar parks due to their permissible voltage range (up to 1500 V), they are increasingly being installed on rooftops for cost-saving reasons. The cost of installing a plant with larger panels (and power output) is lower than for smaller panels (fewer modules, installation materials, additional materials, etc.).Price of solar panels
Solar panels can be divided into economy, medium and high price segments. The choice of module has an impact of around 10-20% on the final price of the solar plant, which makes a difference of around £50-100 per installed kilowatt.When choosing panels based on price level, also objectively consider the house in which the plant is to be installed before making a technological, manufacturer or warranty assessment. Once installed, the solar power plant will become an integral part of your home, which studies have shown to have an impact on the price of real estate.A recent study has shown that a solar power plant can increase the value of a house by up to 4%.The choice of panels can change accordingly for someone who plans to install the plant on a new house with a high real estate value and for someone who builds it on an old farmhouse with a low value.Technology
Monocrystalline or polycrystalline?
Despite the wide variety of solar module technologies that have been and are available, 95% of the panels produced and used worldwide are crystalline silicon (both monocrystalline and multicrystalline silicon) solar panels. This is currently the most widely used technology. Despite the claimed differences often heard on the market, monocrystalline and polycrystalline panels are fundamentally different in terms of their appearance, the efficiency obtained from the same surface area and their cost.Monocrystalline solar panels are characterised by the dark, uniform appearance of the solar cells and thus of the module, the higher efficiency obtained from the same area, and a slightly higher price.
Polycrystalline solar panels, on the other hand, have a lighter blue colour and a lower efficiency compared to monocrystalline panels of the same dimensions, but the price per watt is also correspondingly lower.
This option is more theoretical. The vast majority of panels currently on the market are single crystal. They have become very competitive in recent years in terms of price, advanced technology and efficiency. Polycrystalline panels are mainly used for large solar parks where the cost factor is crucial.If you have received a quote for your home solar power plant with polycrystalline solar panels and a very competitive price, it is most likely that the contractor or manufacturer is trying to sell off the leftover panels of the old technology, as they are not very liquid in the current market for rooftop solar power plants.Solar panels and cell technology
Although the range of module types is very wide, here is an overview of the most common types.
Poly (polycrystalline) solar panels. These are among the longest-lasting solar panels on the market, with the main advantage being their relatively low cost. As a result, these panels have been and are mainly used in ground-mounted solar farms or larger commercial projects.Mono (monocrystalline) solar panels. The main difference from polycrystalline is the higher efficiency generated from the same area and the higher price.Half-cut solar panels. The main difference from monocrystalline solar panels is that the solar cells in the module are cut in half. The main advantages of this are lower losses and higher mechanical resistance. As the module is split into two sections, it has advantages over standard panels in certain shading circumstances (e.g. shading only covers the lower part of the module).PERC Singled solar panels. This is one of the newest technologies used in module production. In this module, the solar cell is cut into 5 or 6 pieces instead of two, and then the pieces are superimposed on each other (like tiles on a roof, for example).These overlays are where the electrical connections are made (instead of the front contacts in standard panels). This technology allows the largest amount of electricity to be extracted from the smallest area. The absence of contacts on the front makes the solar panels more resistant to both mechanical and environmental influences, as well as more solid in appearance. Because they have even more sections than, for example, Half-cut modules, these modules have even better performance under certain shading conditions.Warranty
The most likely scenario, whichever solar power plant you choose, is that it will generate electricity for you for decades. However, in some cases, there are malfunctions of the solar panels. These are the exception rather than the rule. That's what module warranties are for.They usually come in two types - product and performance. These are not the same thing.A product warranty covers the materials and workmanship used in assembling the module. If the performance of the module fails because of the materials or workmanship used during manufacture, the module manufacturer must replace the module or remedy the defect.Over 70% of the world's largest PV module manufacturers have a 10-12 year product warranty. This is a common standard in the market. However, there are companies offering longer warranties of 20, 25 and sometimes 30 years. The length of the warranty does not imply that a panels with a shorter warranty will have a shorter lifetime, but rather indicates the period of time for which the panels manufacturer additionally "insures" the module against malfunctions. It is true that this insurance often has a corresponding effect on the final price of the module. Below you can find product warranty comparisons for the most popular panels used in United Kingdom:| Canadian Solar | 12 |
| Jinko Solar | 12 |
| Longi Solar | 12 |
| ReneSola | 12 |
| Seraphim | 12 |
| Phono Solar | 12 |
| Risen | 12 |
| AstroEnergy | 12 |
| JA Solar | 12 |
| Sharp | 15 |
| Trina Solar | 15 |
| Q Cells | 25 |
| Hyundai | 25 |
| LG | 25 |
| SunPower | 25 |
Solar panels and their appearance
Given that PV solar panels are often mounted on the roof, often in a prominent position, and have a lifespan of several decades, the appearance of the panels is not the last consideration when selecting them. We have already mentioned that mono-crystalline modules have a more solid appearance due to their uniform dark colour. Many module manufacturers also offer monocrystalline modules with a black frame and sometimes with black-coated solar cell contacts. These features add further advantages to the appearance of the module.If the plant is to be installed in a prominent position and aesthetics are not a priority for you, it is worth choosing black solar panels. Recently, the price difference between the standard look and the black solar panels has narrowed considerably and is currently only a few percent.