Solar photovoltaic panels types: Mono vs Polycrystalline vs Thin Film

You are thinking about buying solar panels, but got confused about which type to go for? You’re at the right place. There’s a myriad of variables that you should take into account when you are buying a solar photovoltaic (PV) system – our job here at Energy Informative is to help you sort through them!

In this article, you will learn everything you need to know about the different types of solar panels for home use (mono-, polycrystalline and thin film).

Let’s start with the different types of solar panels currently on the market, list their benefits and downsides, and then look at a few typical scenarios where certain types would be the better than others (hopefully one of them resonates with you).

Three types of modern commercially manufactured panels:

  1. Monocrystalline silicon PV panels
  2. Polycrystalline silicon PV panels
  3. Thick-film silicon PV panels

Day after day, we see headlines showing the growth of solar photovoltaic energy across the globe, from China to India to Germany to the United States. The rising demand for solar power is fueling advances in research and development of solar PV technology. However, in many ways, fundamental solar energy generating technology hasn’t changed much since the introduction of the monocrystalline solar panel in the 1950s. It’s only gotten better, as improvements in efficiency, quality and versatility continue to develop.

Solar PV Technologies

The monocrystalline panel may be the original solar PV technology, but it’s being challenged by both established and emerging new technology on factors like price, efficiency and versatility. Solar PV modules made from polycrystalline silicon, as well as new generations of thin-film solar PV technology, are giving residential, commercial, industrial and utility clients a variety of options to fulfill their solar energy production requirements.

The variety of solar power technologies available run on a scale of efficiency, price, durability and flexibility, depending upon the need of your project. PV solar technology generates power because substances like silicon generate an electrical current when they absorb sunlight, in a process known as the photovoltaic effect. Like semiconductors, solar PV technology needs purified silicon to get the best efficiency, and the price behind PV solar manufacturing is often driven by the crystalline silicon purification process.

Monocrystalline Silicon Solar PV: most efficient

These kinds of solar panels which usually have a polka dot or checkered pattern are made of the smallest solar cells and therefore are the smallest, most efficient types of PV panels.

If your building solar panels with mono crystalline solar cells, they are fragile so they must be mounted in a strong, rigid frame.

Mono crystalline solar panels are also the most expensive of all the main solar panel types. This is due to the fact that they provide more energy production per square foot of module, which makes them essential for limited roof space solar applications.

Generally, monocrystalline silicon solar PV is the best technology to deliver efficiency, as measured by wattage output related to the panel’s size. But this efficiency can come with costs. The best value is solar PV technology is polycrystalline silicon, offering efficiency levels close to monocrystalline panels, but at half the costs in some cases.

Monocrystalline solar is made by growing a single crystal. Because these crystals are usually an oval shape, monocrystalline panels are cut into the distinctive patterns that give them their recognizable appearance: the sliced silicon cells expose the missing corners in the grid-like structure. The crystal framework in a monocrystalline is even, producing a steady blue color and no grain marks, giving it the best purity and highest efficiency levels.

Polycrystalline Silicon Solar PV: best value

These kinds of solar panels (made of cells cut from multiple crystals) are the most popular choice worldwide. In fact polycrystalline has now become the standard in Europe.

Although they are a little bigger, less efficient and require more roof space than the mono-crystalline types of PV panels, they are also less expensive and provide an excellent balance of performance and price. Also recent advances in poly-crystalline cell technology have made these solar panels almost as efficient and heat tolerant as mono-crystalline panels, which makes them even more appealing.

Amorphous (or thin film) Silicon Solar PanelsThese kinds of solar panels are made with cells consisting of a micro-thin layer of silicon applied directly onto a sheet of glass or plastic. They are the types of PV panels that are the least efficient because they use the least amount of silicon in their solar cells and thus take up more roof space than the previous two solar panel types.
Polycrystalline solar is made by pouring molten silicon into a cast. However, because of this construction method, the crystal structure will form imperfectly, creating boundaries where the crystal formation breaks. This gives the polycrystalline silicon its distinctive, grainy appearance, as the gemstone type pattern highlights the boundaries in the crystal.

Because of these impurities in the crystal, polycrystalline silicon is less efficient when compared with monocrystalline. However, this manufacturing process uses less energy and materials, giving it a significant cost advantage over monocrystalline silicon. (Polycrystalline and multicrystalline are often synonyms, but multicrystalline is often meant to refer to silicon with crystallites larger than 1 mm.)

 

Thin-Film Solar PV: portable and light weight

The technology with the lowest market share is thin-film, but while it has several disadvantages, it is a good option for projects with lesser power requirements but needs for light weight and portability. Thin-film technologies have produced a maximum efficiency of 20.3%, with the most common material amorphous silicon at 12.5%.

Thin-film panels can be constructed from a variety of materials, with the main options being amorphous silicon (a-Si), the most prevalent type, cadmium telluride (CdTe) and copper indium gallium selenide (CIS/CIGS). As a technology that’s still emerging, thin-film cells have the potential to be less expensive. Thin-film could be a driver in the consumer market, where price considerations could make it more competitive.

Solar PV Efficiency

According to the U.S Department of Energy, polycrystalline silicon is leading the market share with 55% of PV technology shipments in 2013, compared with 36% for monocrystalline. So far, research has produced polycrystalline cells with a maximum efficiency of 20.4% with monocrystalline technology pushing the boundaries at 25%.

Whether it’s the rooftop of a home or a solar farm for a grid-connected utility, space and area are often a key component of any solar power project, which often makes module efficiency a critical element for project developers. Most solar panels range in efficiencies of 13 to 16%, though some high-end model modules can reach percentages as high as 20%.

For most applications, a mono- or polycrystalline solar PV solution is usually the best option, as these established technologies generally provide the right balance of price, efficiency and reliability. For most commercial and industrial use, the crystalline silicon is still the standard and stands to be for years to come. Vasari Energy has found that the polycrystalline product offers our clients with the desired match of efficiency, durability and price.

Solar Roof Tiles

One more option to consider is solar roof tiles (also known as solar shingles). These are much smaller in size and fit onto your roof over or in place of your regular roof tiles.

You can learn more about solar roof shingles by clicking here to go to the Solar Roof Tiles section of our website.

If you want high powered solar panels, but don’t want to pay for them click here to go to the How To Get Free Solar Panels section of our website.
Choose The Types of PV Panels Right For You

Though, the types of solar panels available each have their own advantages and disadvantages, ultimately the choice is up to you.

If space isn’t a huge issue, we would personally recommend poly-crystalline panels (also known as multi-crystalline panels) as they will give you the most flexibility all-round, along with provide you will many competing brands to choose from.

When choosing between monocrystalline vs polycrystalline solar panels, despite what many salespeople will tell you, there is nothing really to distinguish between the types – except their looks!

Thin-film can be slightly cheaper per kW, but will be at least twice the area, and no-one is 100% sure how much they will degrade in the long term (so get a rock solid performance guarantee!).

There is actually a fourth solar panel technology type available that is being developed in Australia which uses dye sensitised solar cells. This technology is even lower in efficiency than thin film, but promises to be so cheap to make that you’d just put it everywhere to make up for that. It works by mimicking the photosynthesis process in plants.

Factors of Solar Panel Efficiency

Measuring the amount of sunlight that solar panel systems are able to convert into actual electricity is a performance parameter. The outcome determines solar panel efficiency and is always measured in percentages. If the sun produces 100% energy, solar systems are usually able to process 15-22% of that sunpower into usable energy.

To determine solar panel efficiency, panels are tested at Standard Test Conditions (STC). STC specifies a temperature of 25°C and an irradiance of 1,000 W/m2. This is the equivalent of a sunny day with the incident light hitting a sun-facing 37°-tilted surface. Under these test conditions, a solar panel efficiency of 15% with a 1 m2 surface area would produce 150 Watts.

When looking for the most efficient solar panels is that high efficiency does not always provide the highest return on investment. When deciding which solar panels are the best for your project, you should consider a system that will offer you the best financial benefits rather than just the most efficient solar panels. If you have enough space around your house or on the roof, then cheaper panels with lower efficiency could be a better choice since they can produce the same amount of energy you need by simply installing more of them.

This doesn’t mean that premium panels are not worth the money. The high efficiency photovoltaic panels available on the market today are made by reputable companies that use the latest technology, have first-class engineers, and offer high level of quality assurance. These are clear advantages over the cheaper panels.

With this in mind, let’s take a closer look at the different types of solar panels, their applications, efficiency rating, advantages and disadvantages, and hopefully this way you will find the one that’s right for you.

Tips to improve the efficiency of your panels

1. Correct Installation of Solar Panels

Solar panels must be installed correctly. It is necessary that the orientation and tilts angle of solar panel must be installed in the right direction. Hiring a professional Solar PV Installation company can be an ideal choice, which performs correct installation activity on panels. Their experienced technicians install the panel in such a way that you can generate sufficient electricity without any hassle.

2. Keep Solar Panels Clean

Clean solar panels play a significant role in generating optimal electricity. Furthermore, by keeping the solar panels clean, more sunlight access can be done by them. This will lead to more electricity. For cleaning solar panel, you can simply wash the dirt with water. Thorough cleaning of these panels also increases your 20 percent of power production.

3. Avoid Shaded Areas

Shade on solar panels can have an adverse effect on its power output. You can suffer from low power output, when solar panels are arranged in series. Therefore, for an adequate amount of electricity, try to install them in open spaces such as ground, roof and other similar areas where there is nothing covering them such as trees, other building, branches, etc.

4. Cool the Solar Panels

An increase in solar panel temperature can decrease its performance. This problem can occur due to continuous use of solar panels in sunlight, which inevitably heat up the panels. This problem can also be avoided, if you leave at least six inches of air gap between the roof and the solar panels. Through this gap, air can move freely to take away excess heat of this device.

5. Use of Correct Wires

The power of solar panels can be lost, if unsuitable wires are used in this. This is because, use of thin wires convert a large amount of power into heat, which is not correct. So, it is essential to choose a correct wire for solar panels.

6.Orientation and installation is important

Depending on the location, solar panels need to be installed to receive as much sunlight as possible during the day. In the U.S. the ideal positioning is when the panels face south or west because they receive the maximum amount of power from the sun in a day.

The position and angle of your home (ground or roof installation) are probably the most essential detail to consider when installing a solar array. If you are willing to invest some extra money in a solar PV system, solar trackers are worth it. This will considerably improve the efficiency of your panels as they allow the solar array to automatically change position based on the movement of the sun. By allowing the panels to shift their positions relative to the sun, you can see a huge gain in power generation because the panels spend so much more time in the path of direct sunlight. One of the great aspects of tracking is that you can boost your efficiency with a new mounting system without having to actually replace existing panels.

7.Maintenance and cleaning activities

If too much dirt or snow accumulates on the solar panels, the efficiency will decrease and the circuits will be exposed to additional damage. If regular maintenance and cleaning is not done, a complete failure of the solar array can happen. Here’s a more detailed explanation of What You Need to Know About Solar Maintenance and Cleaning.

8.Preventing high temperature impact

During summer months, high temperature levels (especially during heat weaves) will decrease the solar system’s performance. If you leave few inches of gap between the solar modules and the roof or ground, air can move freely and prevent the excessive heat from affecting the panels’ efficiency.

For all its benefits, solar power generation with PV panels is not the most efficient process. On average, a solar cell will convert about 15 percent of the sunlight that hits it into usable electricity. That leaves a lot of room for improvement, and new advances have done just that.

 

Solar Panels Under Extreme Conditions

No single customer wants to end up with solar panels that aren’t technically sound. There are major advantages to having the right type of solar panels installed for your home. In order to guarantee the quality of a solar panel, it is extensively tested under extreme conditions.
Wind

Wind is one the most predicted causes of solar cell damage. Solar panel manufacturers conduct extensive wind tunnel testing to decrease potential damage.
Hail

Hail testing consists of firing artificial hail at a speed of 20 to 30 m/s. Solar cells remain undamaged at these speeds.
Snow

A thick layer of snow can be too heavy for a solar panel. Solar cells stop working when more than 5 cm of snow accumulates on a solar panel and decreases solar panel efficiency by 100%.
Ice

Ice builds up on the surface of solar cells when no silicon coating is applied. The build up of ice can potentially decreases solar panel efficiency by 25 to 100%.
Chemical Residue

For chemical residue to dissolve at least 20 mm of rainfall has to land on the surface of the solar cells. Research has shown a reduction of 0.2% in solar panel efficiency when they are covered in a layer of chemical build up.
UV Degradation

A solar cell structure can be delaminated by UV induced degradation. Another consequence can be the discolouration of individual solar cells.
Damp heat testing

Damp heat testing is carried out to test the durability of solar panels in highly humid conditions. Humidity can lead to corrosion and to module connection failure and an overall decrease of solar panel efficiency.
Insulation Resistance

Insulation resistance is determined by material strength. In weak materials, current leakage can occur on the edges of the solar panel.
Thermal Cycling

Thermal cycling can cause solar panel components to fail. These components include solar cells, interconnections, solder bonds and module connections.

Upon installation, it is important to consider all the factors that could influence solar panel efficiency. Moreover, it is essential to maximise output from the get go.