People always have this notion that choosing to acquire cleaner and greener electricity tends to be an expensive investment. In recent years, though, the cost of photovoltaic technology had significantly declined in general. Thus, making it more affordable than they had ever been for consumers to avail. In 2019, the average price of a PV module had fallen by 32% in comparison to the past two years. According to IHS, the said price trend was predicted to drive global growth in solar energy system installations to almost 90 countries worldwide.
Apart from the pricing, there are far more factors to consider when selecting a solar panel. Aspects such as your capacity requirement, actual physical size, quality of equipment, duration of the warranty, certifications included, and the like. In this guide, we will help you understand what solar panel really is, how it works, what are the different types, and other relevant features, so that in the end, you will gain better insights on how to determine the best solar panel for your needs.
What is a solar panel?
A solar panel is basically a device made up of a collection of solar cells that efficiently converts the light from the sun into electricity. Being the main component in the solar energy system, it is primarily used in electricity production for residential and commercial uses. Furthermore, it is also utilized in other applications including off-grid power solutions, telecommunication equipment, remote sensing, electric vehicles, among many others.
How does a solar panel works?
Solar panels are made up of photovoltaic cells sandwiched in between different layers of semiconductors such as silicon. These photovoltaic cells are responsible for absorbing the sunlight which is then generated into a direct current (DC) electricity. Through the use of inverter technology, the DC energy is converted into a usable form of electricity, the alternating current (AC). After the conversion process, the AC electricity flows through the electrical panels ready to be used by households and establishments or distributed out into the national grid.
What are the major types of solar panels?
About 90% of the photovoltaic solar systems available in the market today are based on a variation of Crystalline Silicon or c-Si. Each form or type only differs according to the purity of the silicon used. Technically, the more thoroughly aligned the silicon molecules, the more effective the PV cells will be at converting sunlight into electricity. Thus, the direct correlation between the purity of silicon with the efficiency of the solar panels must be taken into consideration when choosing for the right system.
The monocrystalline or mono-Si, also referred to as single-crystalline silicon, is the most easily recognizable among all the types. As the name implies, the external panels portray an even coloring and uniform look. This usually indicates a high purity of the silicon. A unique process called Czochralski is used to produce the mono-Si resulting in cylindrical-shaped silicon ingots. Given the nature of its original shape, every four sides of the cylindrical ingots are carefully cut out to form as silicon wafers. In this manner, the performance is optimized while lowering the cost of each mono-Si.
Out of all the types, mono-Si has the highest efficiency rating ranging from 15% to 20%. It also practically occupies a lesser amount of space since it yields the highest power output. Furthermore, mono-Si is also known for its capacity to last longer with a warranty of usually 25 years from most manufacturers. Nevertheless, given the high quality of monocrystalline panels, it also comes with a hefty price tag. It is also worth noting that even though it takes up less space, it is required however to have the full length of the panels exposed to the sunlight. Any impartial coverage, such as from shade, dirt, or snow, may cause the entire circuit to breakdown. Lastly, mono-Si solar panels also produce more silicon wastes due to the Czochralski process which cuts off the corners of the ingots.
The polycrystalline or poly-Si (p-Si), also referred to as multi-crystalline silicon (mc-Si), are solar panels that are made up of silicon wafers too. Nonetheless, poly-Si greatly varies from mono-Si in terms of its production. Unlike the latter, poly-Si does not involve the Czochralski process. Instead, fragments of raw silicon are melted together in square-shaped molds, then cooled and cut into wafers. Poly-Si is easy to tell apart from mono-Si because of its perfectly rectangular appearance rather than the more rounded edges of the mono-Si.
Mainly because poly-Si has lesser silicon purity, its efficiency is expected to be lesser in comparison to that of the mono-Si. In addition, it also requires a larger space to provide the same amount of electrical power output than monocrystalline. Nevertheless, poly-Si panels cost cheaper and they give off fewer silicon wastes as it is specifically molded to a precise size and shape.
- Thin-Film Solar Cells
The thin-film solar cells (TFSC), otherwise called as thin-film photovoltaic cells (TFVC), are composed of one or more thin layers of photovoltaic material deposited onto a substrate. The different types of TFSC are as follows:
- Cadmium Telluride
The Cadmium Telluride or CdTe is one of the most commonly used photovoltaic materials for TFSC. To produce this type, the manufacturers place a thin film of CdTe in between transparent conducting layers to aid in the absorption of sunlight. In addition, this type also includes a layer of glass on top to give protection to the panel.
- Amorphous Silicon
The Amorphous Silicon or a-Si is another type of TFSC that although have silicon in its composition, is not made out of solid silicon wafers unlike the mono-Si and poly-Si solar panels. Instead, the a-Si TFSCs are composed of non-crystalline silicon positioned on top of a layer of glass, plastic or metal.
- Copper Indium Gallium Selenide
The Copper Indium Gallium Selenide or CIGS is one of the most popular types of thin-film technology. This kind of TFSC contains all the four elements sandwiched in between two conductive layers of either glass, plastic, aluminum or steel material. Moreover, electrodes are connected in the front and back area of the material itself in order to capture the electrical currents.
Thin-Film Solar Cells has an overall homogenous look hence more appealing than crystalline-based panels. It is also known for its flexibility thus suitable to use for a wider array of potential applications. TFSC relatively costs cheaper, however, it is also less space-efficient at the same time. As a result, the user may end up spending more on the equipment such as the support structures and cables as it is likely to occupy more space. Furthermore, TFSC degrades faster than mono-Si and poly-Si that is the reason why manufacturers issue shorter warranties for this type of solar panel.
|SOLAR CELL TYPE COMPARISON TABLE|
|Monocrystalline||15% – 20%||High efficiency rateSpace-efficientHigh lifetime value||ExpensiveRequires full heat coverageMore silicon wastes|
|Polycrystalline||13% – 16%||Less expensiveFewer silicone wastes||Lesser efficiency ratingSlightly less space-efficient|
|Thin-Film Solar Cells||7% – 13%||Easier to mass-produceFlexibleLess sensitive to high temperature and shaded coverageRelatively low cost||Requires large surface areaShorter lifespan|
What are the classifications of solar panel quality?
The quality itself of the solar panels is one of the bases of its price points. Of course, the higher the quality, the more expensive it becomes. Hence, you have to make sure that you get the most out of what you paid for. The classification below will give you an idea of what to expect if ever you decide to choose between a low-end, mid-range, or high-end quality solar panels.
High-End Solar Panels
The high-end panels are made from the highest-grade materials and are manufactured with absolute precision and durability. These premium modules are expected to acquire an efficiency rating as high as 20% and a warranty that covers at least a decade or more. In addition, these modules are also built with favorable temperature coefficients making them more suitable to be installed in locations that tend to have an extremely hot climate. Given the impeccable quality, expensive pricing can be anticipated for this as well. The high cost can be prohibitive for some but if your goal is to optimize your solar energy system for a very long time, then high-end panels might be a great investment for you. Primarily because it is guaranteed to last long enough to allow you to offset its purchase price through the benefits you gain from the solar power it produces throughout the course of years or even decades.
Mid-Range Solar Panels
The majority of the solar panels available in the market today can be classified as mid-range. This classification of modules offers a fair compromise between the price, quality, and longevity. Performance-wise, the mid-range panels are considered reliable and durable. In average, it is known to deliver an efficiency rating of 15% more or less. These type of solar module is suitable for customers who want to set up a dependable solar energy system with moderate risks involved and more affordable cost.
Low-End Solar Panels
The low-end solar panels are obviously the least expensive among the classifications of solar panels. Its cheap price point makes it appealing to the market. A closer look, however, its efficiency and durability are reasonably compromised in order to accommodate the low-cost of its production. Most of the economy modules offer less than 15% efficiency rating and comes with a poor temperature coefficient. They are built with less regard of a prolonged lifespan, hence, they are most often provided with shorter warranties by the manufacturers.
What are the tiers of solar panel manufacturers?
Apart from the quality, the reliability of the company behind the production of the solar panels is also worth considering. This tier ranking system will help consumers understand and mitigate the risks involved with their choices of solar panels and their corresponding brand. The tiers are based on specific metrics including but not limited to the following: Experience, Manufacturing Scale, Durability & Quality, Technical Performance, Sustainability, Innovativeness, Price Competitiveness, and more.
Tier 1 Solar Panel Manufacturers
The tier 1 solar panels are produced by the top 2% of the photovoltaic module manufacturers. These are the big brands that had already established a solid reputation in the industry. Mostly vertically integrated, so every phase of the manufacturing process is closely monitored and controlled by the company itself. Furthermore, they invest heavily in research and development thus advanced robotic technology is inclinedly used in the manufacturing processes. Tier 1 solar cells are made from the purest and highest-grade silicon
Tier 2 Solar Panel Manufacturers
The tier 2 solar panels involve small to medium scale manufacturers often with at least 2 to 5 years of experience in the solar industry. These companies are reliant on both robotic and manual human assembly of its product lines. Research and development on this level are given a priority of little to none.
Tier 3 Solar Panel Manufacturers
The tier 3 solar panels comprise as much as 90% of the photovoltaic manufacturers today. Technically, companies in these level participate in the assembly process only. They do not in any way take part in the production of solar cells and neither does it invest in research and development. Furthermore, the majority of its production line is done manually by human operators resulting in high tendencies for quality inconsistencies. That is the reason why solar panels from this tier are cheaper at a cost since its reliability and durability may not be of utmost assurance.
What are the general factors to consider when choosing a solar panel?
Cost versus Value
Cost is one of the most common factors why consumers are easily taken aback in owning a solar energy system. However, given the declining price trend of photovoltaic technology nowadays, the cost had become more competitive thus more accessible for people. Nonetheless, do not dismiss the fact that not all solar panels are created equal. Some are less expensive because the products are made of low-quality materials. Meanwhile, other modules are priced too expensively mainly because top-grade materials were used and are designed to last the user for a longer period of time. Hence, it is rather important to evaluate the intrinsic value of the module in the long run, instead of simply looking into its upfront cost. In that way, you have a better insight which product will deliver quality performance and greater return on investment in the end.
The nameplate rating represents the power output of the solar panel. It is the amount of direct current (DC) electricity generated within the ideal conditions. Depending on the size and quality, modules are usually rated as 200 or 400 watts. Nevertheless, in reality, it is the least likely for the panels to achieve its expected ratings. That is because of certain external variables such as atmospheric conditions, environmental temperature, amount of sun exposure, angle or position of its placement on the roof, presence of structures that can possibly cause shading, and among many other circumstances than can cause an impact on the efficiency rating.
This is a range given by the manufacturers specifying the estimated percentage of deviation from the module’s rated power. For instance, the solar panel has a nameplate rating of 200 watts and was given a tolerance of -10%/+10%, that means the module is most likely capable of delivering a power output of 180 up to 220 watts in the actual application.
In general, the temperature has a direct correlation with the ability of any electronic device to generate electricity. In solar panels, it is represented as the temperature coefficient. This basically refers to the percentage of decline in power output for every 1 degree Celsius of the increase in temperature from a standard of 25°C or 77°F. Most solar modules have a temperature coefficient of approximately -0.3%/°C up to -5%/°C. Just always remember, the lower the percentage, the better.
This rating specifically tells us how efficient the solar panel converts sunlight into electrical energy. Most modules have an efficiency rating between 13% to 20%. Of course, the higher the rating, the better. This may not seem to sound a lot but, so far, the highest rating recorded under the perfect conditions of a laboratory reaches up to 25% only. In actual, the remaining 80% or more of the energy produced simply dissipates as heat, unfortunately.
Duration of Warranty
The warranty provided by the manufacturers often express the company’s confidence in the quality of its products. There are actually two types of warranties. First, is the Performance Warranty. This type provides consumers the guarantee against the degradation of the solar cells. As a standard in the industry, it is given a duration of 25 years. Nevertheless, be aware that this type of warranty is usually considered by many as a mere marketing strategy. That is because it is very easy for some manufacturers to maneuver out of the consumer’s claims. Thus, it oftentimes leaves the customers with worthless promises in the end. Second, is the Product Warranty. This type of warranty provides coverage to defective materials and workmanship. It is usually given a duration of between 5 to 10 years. Among the two, this is what buyers should give more attention to as this mainly provides users the coverage against the technical problems that the solar panels may encounter in the future. So make sure to select modules with the longest possible product warranty from the manufacturer.
How are solar panels installed?
Apart from determining which type of solar module, it is also equally important to understand the circumstances involved in the installation of it in the homeowners or the facility’s roofing system. Below are the six main steps that are usually followed to get the solar panels up and running.
Planning is very crucial in the success of your solar energy system. Obtaining professional services from experienced engineers and installers will help you determine the most secure and optimum way to install your panels. Thus, ensuring the general safety and enhancing the value for money. On this stage, the trained professionals will conduct thorough assessments on the dimensions of the solar panels, roof type and its prevailing structural condition, the degree of the roof angle, tendencies for shading in the area, electrical status, and compatibility of the system are just a few among the technical details that need to be meticulously taken and evaluated in order to come up with the most appropriate installation plan for your solar panels.
Install Physical Support
Once the planning has already been finalized, you may now proceed with preparing your installation by attaching the necessary physical support. The usual fixtures used in this phase are brackets for sloped roofs and the mount rails for flat-surfaced roofs. To ensure firm and safe attachment, it is important to fasten the supports in the house’s rafters or trusses. Moreover, take into careful consideration the correct angle of the fixture’s placement as initially planned with the engineer or installer in order to achieve the maximum exposure from the sun.
Solar Panel Attachment
After the physical supports are ready, the attachment of the solar panel follows. With utmost care in handling, transport the modules up in the roof and lay them accordingly onto the support fixtures. Fasten tightly to guarantee that it will not fall off under any circumstances. At this point, reassess if additional brackets or mount rails are needed to further assure the stability of the modules.
Connection of Wirings
Once the solar panels are physically attached in the roof, the electrical phase of the installation may now ensue. Nevertheless, prior to connection of the wirings, the installer must make sure that each and every wire is properly insulated and waterproofed for protection. Furthermore, it is also very critical to always remember to connect a ground wire from the bracket or mount rail into the earth to avoid incidences of a shock to occur.
Photovoltaic Components Set Up
Now that the solar panels are successfully installed and wired, the rest of the photovoltaic components may now be set up. The inverter and the rest of the remaining parts of the system should ideally be set up in a secure and most often obscure location such as in the garage or a shed. Moreover, it is also essential for the facility to be dry, well-ventilated, and is consistently under room temperature to properly maintain the integrity of the components.
Connection of the Inverter into the AC Breaker Panel
Once the installation and setup of the entire solar energy system have been established, it is now time to finalize the connection of the wirings. First thing’s first, make sure the main breaker is shut off. The installer may use a voltage tester to double-check safety. Connect the photovoltaic wires to the direct current (DC) disconnect switch and to the other PV system components. Lastly, connect the main DC disconnect to the inverter.
How to maintain solar panels?
Post-installation and all throughout the years to come, it is important to periodically maintain the integrity of the solar panels to ensure the consistency of its performance and the longevity of the module themselves.
Solar Panel Cleaning
The most basic maintenance you can do to take care of your solar panels is simply to remove any debris that may block the rays of the sunlight from being absorbed into the module. Rubbish such as leaves, snow, dirt and dust accumulation can easily be washed out by water. Furthermore, there are also cleaning kits available in the market targeted especially for routine cleaning of solar panels. The kit mainly includes liquid soap, a wiper, and brushes of different sizes and lengths. The cleaning can be done at least twice a year or as often as the need arises.
Solar Panel Monitoring System
A solar panel monitoring system allows you to keep track of the daily performance of your solar energy system. This also shows how much carbon dioxide emissions your system is emitting into the atmosphere. In addition, this also detects which areas of the solar panel are in need of a check-up or repair. Thus, making it easier for the service company to pinpoint which exact components requires servicing or replacement.
Apart from your routine basic cleaning, preventive maintenance can be performed annually to guarantee the optimum condition of the solar panels. On this procedure, a thorough visual inspection is implemented to check for the occurrence of any but not limited to the following:
- Water damage
- Roof drainage issues
- Vegetation growth
- Animal infestation
- Erosion of physical support
- Corrosion on electrical enclosures or the rack system
- Excessive wears or cracks
- Loosed or exposed wirings
- Burn marks or discolorations
- Missing bolts
The solar panel is the main component of your solar energy system. It carries the most important task of collecting light from the sun. The more effective it is in gathering sunlight, the more energy there is to be converted into a usable load of electricity to power homes or establishments. Hence, it is essentially vital to know exactly which type and specifications are suitable for your requirements in order for you to be able to reap the maximum benefits and gain a favorable return of investment eventually. Furthermore, the efficient use of the solar energy system helps individuals achieve the ultimate goal of promoting cleaner electricity and diminishing carbon footprints.