Why are Polycrystalline Solar Cells so Popular?
Polycrystalline (sometimes also called multicrystalline) solar panels are the most common because they are often the least expensive. They are the middle choice in the marketplace. almost as good as single cell monocrystalline silicon panels but generally with a better efficiency than thin film solar panels.
Polycrystalline cells can be recognized by a visible grain, a “metal flake effect”. The solar cells are generally square in shape, and may have a surface that looks somewhat like a mosaic. That’s because of all the different crystals that make up the module.
How Polycrystalline Cells Are Made
The reason polycrystalline solar panels are less expensive than monocrystalline solar panels, is because of the way the silicon is made. Basically, the molten silicon is poured into a cast instead of being made into a single crystal.
This material can be synthesized easily by allowing liquid silicon to cool using a seed crystal of the desired crystal structure. Additionally, other methods for crystallizing amorphous silicon to form polysilicon exist such as high temperature chemical vapor deposition (CVD).
In the cast process, silicon pieces are melted in a ceramic crucible and then formed in a graphite mold to form an ingot. As the molten silicon is cooling a seed crystal of the desired crystal structure is introduced to facilitate formation.
Although molding and using multiple silicon cells requires less silicon and reduces the manufacturing costs, it also reduces the efficiency of the solar panels.
Note: 1366 Tech (founded by former MIT professor) has developed a machine that can produces polycrystalline solar cells about 30 times faster than current technologies … which should lead to lower priced polycrystalline modules in the near future. For more details read this recent article in our Solar News and Views blog site.
Manufacturers of Polycrystalline Solar Panels
Common brands of panels made up of polycrystalline modules include: SunTech Power BP SX (formerly Solarex) Canadian Solar Jaiwei Kyocera Luxor Mitsubishi Electric Quantum Solar Schott, Sharp Sunenergy Tenesol Trina Solar Yingli and Yohkon (to name just a few).
Generally speaking, polycrystalline panels have an efficiency that is about 70% to 80% of a comparable monocrystalline solar panel. The most efficient polycrystalline panels are built by Mitsubishi Electric Corporation. In February 2010, Mitsubishi set two world records for photoelectric conversion efficiency in polycrystalline silicon photovoltaic (PV) cells, which was achieved by reducing resistive loss in the cells. The conversion efficiency rates have been confirmed by the National Institute of Advanced Industrial Science and Technology (AIST), in Japan.
Another one of the world records, which Mitsubishi Electric has now renewed for the third consecutive year, is a 19.3-percent efficiency rating for photoelectric conversion of a practically-sized polycrystalline silicon PV cell of 100 squared centimeters or larger, with the PV cell measuring approximately 15cm x 15cm x 200 micrometers. The rating is 0.2 points higher than the company’s previous record of 19.1 percent.
The second world record, achieved with the same technologies in an ultra-thin polycrystalline silicon PV cell measuring approximately 15cm x 15cm x 100 micrometers, is an efficiency rating of 18.1 percent, a 0.7-point improvement over the company’s previous record of 17.4 percent.
Currently the solar industry is investing lots of money in research and development to find ways to increase manufacturing costs and boost overall efficiency of the solar modules. As you can see from the work done by Mitsubishi, these improvements are primarily incremental in nature and are more on the manufacturing side than on the efficiency side.
Benefits of Polycrystalline Solar Panels
Lower Per Panel Costs
are much simpler to produce, and cost far less to manufacture. This makes them much less expensive for buyers, especially those with small to medium sized roofs.
Durability and Longevity
The durability and longevity are comparable to their monocrystalline cousins – namely at least 25 years. Polycrystalline solar panel modules could put solar power into the hands of people who could not afford the polycrystalline cells.
Besides being able to produce energy from the sun and thus help reduce greenhouse gases and related environmental problems of extracting fossil fuels (e.g., the BP oil spill, coal mining accidents, geo-political resource wars, etc.), some polycrystalline solar panel manufacturers (e.g., Mitsubishi) go the extra mile by inventing new technologies that eliminate expensive soldering (which also contains lead) making these panels even more environmentally friendly.
Lower Electric Bills
Any solar system can and probably will result in a lower electricity bill. Even though the amount of electricity produced from a polycrystalline solar panel is less than from a monocrystalline panel – so are the costs … so you have to fine tune your analysis to see which one has the better payback over the time frame of your analysis (e.g., 20 years in Europe – which is usually the time period of the Feed in Tariffs).
Disadvantages of Polycrystalline Solar Panels
Polycrystalline solar panels are somewhat fragile, and can be broken if hit by a falling branch or reasonably heavy object flying through a strong wind.
There is strong price competition between polycrystalline manufacturers, and this can be both a good thing (in that it tends to keep low) or a bad thing (some manufacturers may not be able to withstand the competition and won’t be around to honor their product or performance warranties).
Current Market Overview
The current market for solar PV is dominated by crystalline silicon (c-Si) solar panels (around 80%), and c-Si solar technology is expected to continue to dominate in the residential and commercial rooftop markets due to higher efficiency and rapidly reducing costs.
There has been a 40% price reduction since the middle of 2009, largely as a result of the improved supply of polysilicon, which is the basis of c-Si-based panels. When supply was constrained by limited production of polysilicon, the price reached over 300/kg. Now, the cost has fallen to below 100/kg and supplies are readily available for mass production — driving a continuing decline in panel prices.
Lower cost c-Si panels support a key goal for solar known as grid parity, where it costs the same to generate power on their rooftops as it does to buy it from the grid. This point has already been reached during the peak demand period. According to the European Photovoltaic Technology Platform group, solar PV is expected to reach grid parity in most of Europe over the next 10 years.
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Monocrystalline Solar Panels
All across the globe, companies, governments, and individuals are working hard to reduce their carbon footprints and slow climate change. While solar panels are no miracle solution, many environmentalists would argue that they work better than most other alternatives on the market. The key is choosing the right solar panel for your needs. So, what are the main differences between a polycrystalline vs monocrystalline solar panel?
The reason so much debate exists around monocrystalline vs polycrystalline solar panels is that they are the two most commonly used types. They are separated by differences in the crystalline silicon and the manufacturing process. These factors also affect the way they function. However, there is a third contender worth mentioning.
What Are Monocrystalline Solar Panels?
When reviewing the main types of solar panels, these are known for their black appearance. They are made from single-crystal silicon and feature more rounded edges. These are also called monocrystalline solar cells.
Despite being one of the most expensive options, the monocrystalline solar panel is a common choice in commercial, residential, and DIY solar installations.
What Are Polycrystalline Solar Panels?
When shopping for solar system parts, you likely noticed a massive cost discount for choosing a polycrystalline solar panel. These solar panels are made from straight-edged PV cells that feature a blue color. This type is also referred to as a poly solar panel or a multi-crystalline panel.
What Is a Thin Film Solar Panel?
If you have seen either stick-on solar panels or flexible solar panels before, then you have encountered thin-film solar panels. These solar panel options are becoming increasingly popular for mobile applications where weight is a concern.
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Polycrystalline Versus Monocrystalline Solar Panels: Manufacturing Process
The primary difference comes down to the foundational components.
When creating a monocrystalline solar panel, the manufacturer forms the silicon into bars and then cuts them into wafers. When creating a polycrystal solar panel, the manufacturer melts fragments of silicon together to form wafers.
The poly crystalline solar panel might seem like a more complicated product, but it’s actually easier for panels manufacturers to make. This is the main reason why it costs so much less.
Difference Between Monocrystalline and Polycrystalline Solar Cells: Efficiency Rates
The manufacturing differences also create variations in efficiency. According to the American Solar Energy Society, monocrystalline solar cells are known for high efficiency ratings in the 15% to 20% range. In contrast, polycrystalline solar cells have efficiency ratings in the 13% to 16% range.
The difference in how much each type of panel produces is caused by the electrons not having as much room to move around in a polycrystalline solar cell. This stems from the presence of too many crystals.
Mono vs Poly Solar Panel: Temperature Coefficient
1 to 1.50 per watt for mono panels. In contrast, poly panels cost only 0.90 to 1 per watt. This means that a mono installation for 5,000 watts could total as much as 7,500. Meanwhile, a poly install for 5,000 usually costs no more than 5,000.
Note that this is a general price comparison. There are other factors that could affect the cost of purchase and installation:
- Material and labor shortages
- Placement choices
- Economies of scale
- Additional components
- Complexity of full installation
What Type of Panel Should You Get for Your Solar Panel System?
Now that you have a good idea of how solar panels work, it’s time to connect the dots to your specific needs. Use these three main factors as your starting point.
What is the main goal of your solar installation? Do you want to reduce your dependence on the grid, lower your energy bills or completely eliminate grid dependence? When making a decision, you will also need to consider local laws, such as whether off-grid living is permitted or whether your energy company will buy your excess solar during daylight hours.
The fewer panels you intend to install in your solar setup, the more important it is to choose the more efficient option. Otherwise, you could risk being underpowered. There is an especially high risk of being underpowered if your property will be 100% off-grid. When determining the solar installation size you need, start with the expected power consumption of your premises.
Not all customers include batteries in their setups, but if you plan to be 100% off-grid, batteries are necessary. Lithium batteries are the best because they can handle lower and more frequent discharge rates compared to all alternatives. Consequently, you may get away with fewer panels without risking battery health on cloudy days. Similarly, if you have fewer batteries, you might need more panels to offset lower storage.
Monocrystalline Vs Polycrystalline Solar Panels 2022: Which Is Better
If you have decided to go solar, then this article is for you. Choosing between the right solar panels for your home might seem like a complicated task. You have to consider a lot of factors such as climatic conditions, budget, space required and much more. This article might help you in choosing suitable solar panels for your home or business.
While selecting solar panels you may come across two common categories: Monocrystalline solar panels and Polycrystalline solar panels.
Both monocrystalline and polycrystalline solar panels convert sunlight into energy using the same technique i.e. Photovoltaic Effect. Solar panels consist of solar cells that are made from layers of silicon, phosphorus, and boron. The composition of silicon in these solar cells is a major difference between monocrystalline and polycrystalline solar panels.
Monocrystalline Solar Panels
Generally, monocrystalline solar panels are considered under the premium category due to their high efficiency and sleek aesthetics. As the name suggests, the monocrystalline solar panels consist of single silicon crystals and often go by the name of single-crystal panels.
The monocrystalline cells are made from pure silicon which is shaped into bars. These bars are then sliced into thin octagonal-shaped wafer forming cells.
The pure silicon gives these cells their unique dark blue hue because of which they are easily identified from other types of solar panels. The monocrystalline solar panels have higher efficiency as compared to their counterparts.
Further advancement in monocrystalline cells is the Half Cut cell. In this technology the square-shaped cells are sliced in the middle, resulting in twice the quantity of cells, half the size of the single square cell.
These cells are interconnected in such a way that the top portion of the panel has all cells associated in one series and the bottom half in another series. This permits the panels to proceed with power generation in the top half regardless of whether there is a shadow on the base portion of the board. Thus, the general power generation from half-cut cells is higher irrespective of shadow issues.
Another advanced technology which is combined with Monocrystalline Half Cut cells is the PERC technology (Passivated Emitter and Rear Cell).
Traditional solar panels absorb sunlight to a certain extent and some light passes straight through them. An additional layer is added to the back of the cells in PERC technology. This allows the unabsorbed sunlight to be absorbed again from the rear side of the panels, making them even more efficient.
Polycrystalline Solar Panels
Polycrystalline solar panels generally have a lower efficiency than monocrystalline solar panels. This means that you will require more panels to get the same output power. But this doesn’t mean that they are less preferred. Polycrystalline solar panels have a cost advantage and are more affordable compared to other solar panels.
The polycrystalline solar panel or “multi-crystalline” panels are also composed of the same materials i.e. silicon, but the process of manufacturing the cells is much simpler as compared to monocrystalline cells.
Unlike monocrystalline cells, polycrystalline cells are not made from a single crystal of silicon. Polycrystalline cells are made by melting many silicon fragments together which are then poured into square moulds for cooling.
After cooling, thin wafers are sliced out of these moulds and assembled to form cells. These cells are easily identified by their shining blue hue with straight edges.
Comparison chart: Monocrystalline v/s Polycrystalline Solar Panels
|Particulars||Monocrystalline Solar Panels||Polycrystalline Solar Panels|
|Efficiency||High (19-21%)||Low (15-17%)|
|Appearance||These panels have black or dark blue hues with octagonal shape||These panels have blue hue with square edges|
|Temperature coefficient||Lower (0.35% per degC)||Higher (0.4% per degC)|
|Annual Degradation||Lower (0.55% per year)||Higher (0.7% per year)|
|Lifespan||25 years||25 years|
|Advantages||Energy efficientHeat-resistantLesser power output reduction over time||AffordableLess wastage in manufacturing processLow carbon footprint|
|Disadvantages||ExpensiveHigh carbon footprint||Low heat resistanceLower energy efficiency|
Let’s simplify this chart Monocrystalline vs Polycrystalline chart further for a better understanding:
Cost is the first consideration when it comes to the ever looming debate: Monocrystalline vs Polycrystalline, which of the two is better! So, let us elaborate on the topic.
Monocrystalline solar panels come under the category of premium solar panels and are expensive. This is because of the single silicon crystal used in making the cells and the complex manufacturing process.
On the other hand, polycrystalline solar panels are manufactured in a much simpler way by melting silicon fragments and cutting them into thin wafers. Because of this, polycrystalline solar panels are much more budget-friendly than monocrystalline solar panels.
Next in our list of Monocrystalline vs Polycrystalline solar panels is their power capacity.
The power rating of solar panels is measured in Wp, i.e. Watt peak, which is the peak DC power generated by the panel under standard testing conditions. Different types of solar panels have different capacities in Wp due to their different efficiencies.
Mono-PERC Half Cut panels, which combine monocrystalline Half Cut cells with PERC technology have the highest power rating among commercially available solar panels. This is because of the high efficiency of monocrystalline cells combined with PERC technology.
Panels of up to 540 Wp DC power are available from most of the Tier 1 Chinese solar panel manufacturers. Polycrystalline solar panels are typically available in the range of 320 to 370 Wp.
Efficiency Temperature Coefficient
Monocrystalline solar panels are highly efficient and generate more energy even during hot summers. Monocrystalline cells allow more space for the flow of electrons which helps in generating more energy.
Polycrystalline solar panels have lower efficiency and require more panels to generate the same output as monocrystalline solar panels. These panels are also more affected by higher temperatures.
The power generation capacity of Monocrystalline panels reduces by approximately 0.35% per 1 deg C increase in temperature.
For polycrystalline panels, the degradation is around 0.40% per deg C.
Let’s now explore another very important feature in the Monocrystalline vs Polycrystalline debate: Annual Degradation!
The power rating of the panels is reduced over the 25-year life of the panel. Both mono poly panels reduce in rating by about 2% after 1 year of operation.
In years 2 to 25, monocrystalline panels reduce in rating by 0.55% per year and polycrystalline panels by 0.7% per year.
Hence, monocrystalline panels lose approximately 15% of their power rating at the end of 25 years and polycrystalline panels lose about 19% over the same period.
Monocrystalline solar panels tend to have black or dark blue hues with octagonal shapes. Whereas, polycrystalline solar panels have blue hues with square edges.
Both monocrystalline and polycrystalline solar panels generally have an average lifespan of 25 years. However, while considering the lifespan of solar panels, you should always look for companies that offer better power production warranty.
Monocrystalline v/s Polycrystalline Solar Panels: Deciding Factors
If you are still confused about the decision between monocrystalline and polycrystalline solar panels, then consider these factors before making your decision.
If you have limited rooftop space available for solar installation, you should consider going for monocrystalline solar panels as 50 to 60% higher power capacity can be achieved in the same area as compared to polycrystalline panels. While the up-front cost of mono panels is higher, having a higher capacity plant will be beneficial in the long run by reducing your electricity bills much more.
On the other hand, if you have ample rooftop space available to go for a larger solar installation, then you can consider polycrystalline solar panels as a more economical option.
If you are looking for aesthetically pleasing solar panels for your roof, then you might consider monocrystalline solar panels. Their sleek design and black hue offer an aesthetic appeal to your solar structure. Alternatively, if you like to go with the simpler structure, then you can consider polycrystalline solar panels, which have a light blue tint.
Monocrystalline and Polycrystalline solar panels are the two most common categories of solar panels.
There are many factors that one should consider while choosing between these two solar panels. Although both monocrystalline and polycrystalline are made from silicon, they have different output and performance characteristics.
Whilst monocrystalline solar panels are preferred due to their efficiency, polycrystalline solar panels are popular as they are more affordable. However, you should consider all the pros and cons as mentioned in this guide on Monocrystalline vs Polycrystalline solar panels before making your decision.
Frequently asked questions
What is better Monocrystalline or Polycrystalline?
If your preference is based upon efficiency and appearance, Monocrystalline panels are better. If you’re more concerned about the cost, Polycrystalline is the better option of the two.
Which type of solar panel is best for home use?
Polycrystalline solar panels are best for residential purposes.
Is Monocrystalline more expensive than Polycrystalline?
Yes. The manufacturing process of Monocrystalline panels is much complicated than polycrystalline panels. Hence, it’s more expensive.
Monocrystalline vs. Polycrystalline Solar Panels
Solar manufacturers are constantly testing new technologies to make their solar panels more efficient.
As a result, solar manufacturing has branched into a wide range of cell technologies. It can be confusing to try to figure out why you should pick one option over the other.
Ever wondered about the difference between monocrystalline vs. polycrystalline solar panels? Or N-type vs. P-type cells? You’re in the right place. This article will give a high-level overview of the major solar cell technologies in play and explain the pros and cons of each.
Monocrystalline vs. Polycrystalline vs. Thin-Film Solar Panels
The first set of terms describes how solar cells are formed out of raw materials.
Traditional solar cells are made from silicon, a conductive material. The manufacturer shapes raw silicon wafers into uniformly-sized silicon cells.
Solar cells can either be monocrystalline (cut from a single silicon source) or polycrystalline (from multiple sources). Let’s look at the differences between the two options.
Monocrystalline Solar Panels
Monocrystalline solar panels contain cells that are cut from a single crystalline silicon ingot. The composition of these cells is purer because each cell is made from a single piece of silicon.
As a result, mono panels are slightly more efficient than poly panels. They also perform better in high heat and lower light environments, which means they will produce closer to their rated output in less than ideal conditions.
However, they cost more to produce and that higher cost is passed on to the buyer. Mono panels are a bit more expensive than poly panels of the same wattage.
The manufacturing process for mono panels is also more wasteful than the alternative. Mono panels are cut from square silicon wafers and the corners are shaved off to make the distinct cell shape shown in the picture below.
Lastly, mono panels have a uniform black look because the cells are made from a single piece of silicon. I personally think these look better than poly panels, but obviously, that is just a matter of preference.
Polycrystalline Solar Panels
Polycrystalline solar cells are blended together from multiple pieces of silicon. Smaller bits of silicon are molded and treated to create the solar cell. This process is less wasteful because hardly any raw material is thrown out during manufacturing.
The blended makeup of the cells gives poly panels their iconic blue color. If you look at them up close, you’ll see the texture and color is uneven due to the way the cells are made.
Poly solar panels are slightly less efficient than mono panels due to imperfections in the surface of the solar cells. Of course, they’re cheaper to manufacture which means they cost less for the end-user.
Thin Film Solar Panels
The majority of solar panels deployed today are made from either monocrystalline or polycrystalline solar cells.
There is a third type of solar technology, called thin film panels, which are usually deployed for large-scale utility projects and some specialty applications. Thin film panels are created by depositing a thin layer of conductive material onto a backing plate made of glass or plastic.
Thin film panels typically don’t see use in residential installs because they’re much less efficient than mono or poly panels. With roof space at a premium, residential customers go with more traditional crystalline silicon panels to maximize production from the space available to them.
However, thin film technology is less expensive to manufacture, and it becomes a more cost-effective option at a larger scale. For commercial and industrial projects without any space restrictions, the lower efficiency of thin film technology doesn’t really matter. Thin film panels often end up being the most cost-effective option in these situations.
In addition, if you’ve ever seen flexible solar panels on an RV or boat, thin film technology is what makes those possible.
Because they are (as the name implies) much thinner than a traditional silicon wafer, the thin film can be deposited onto plastic to create flexible solar panels. These panels are especially nice for RVs and mobile use when you might not have a flat surface to mount the panel.
N-Type vs. P-Type Solar Cells
The previous section covers the process by which raw material is formed into silicon wafers.
This section has to do with the process by which those wafers are treated to turn them into a functioning solar cell that can generate an electrical current.
What are P-Type Solar Cells?
P-type cells are usually built with a silicon wafer doped with boron. Since boron has one less electron than silicon, it produces a positively charged cell.
P-type cells are affected by light-induced degradation, which causes an initial drop in output due to light exposure. This has historically been the most common treatment method for solar cells.
What are N-Type Solar Cells?
N-type cells are doped with phosphorus, which has one more electron than silicon, making the cell negatively charged.
N-type cells are immune to boron-oxygen defects, and as a result, they are not affected by light-induced degradation (LID). As you might expect, these are positioned as a premium option because they degrade less over the life of the panel.
Here are a few examples of N-type panels:
N-Type Solar Panels
Most of the panels we sell use P-type cells, which can degrade a little faster, but still perform well for 30 years.
When you consider the lower cost of P-type cells, it typically pays to go with a cheaper module that degrades a little more, as opposed to a substantially more expensive panel with slightly less degradation. But that assessment may change as N-type technology advances and costs drop over time.
Other Differences in Solar Cell Technology
PERC stands for Passivated Emitter and Rear Cell technology. PERC cells are distinguished by an extra layer of material on the backside of the solar panel, called the passivation layer.
Think of the passivation layer like a mirror. It reflects light that passes through the panel, giving it a second chance to be absorbed by the solar cell. solar radiation is absorbed by the cell, which results in a higher efficiency panel.
PERC cell technology is gaining traction because the inclusion of the passivation layer doesn’t add huge manufacturing delays or expenses. The efficiency boost more than justifies the extra step in the manufacturing process.
Aleo Solar has a good article that gives more context on the history of PERC technology as well as more technical info about how it works.
PERC Solar Panels
Half-cut cells are exactly what they sound like: solar cells cut in half.
The smaller size of half-cut cells gives them some inherent advantages, mainly (you guessed it) improved efficiency over traditional cells.
Solar cells transport electrical current through ribbons that connect neighboring cells in a panel. Some of this current is lost due to resistance during transport.
Because half-cut cells are half the size of a traditional cell, they generate half the electrical current. Lower current between cells means less resistance, which ultimately makes the cell more efficient.
In addition, half-cut cells can be more shade-tolerant. When shade falls on a solar cell, it not only reduces the production from that cell, but every other cell connected to it in series as well.
A traditional solar panel may have 60 solar cells, wired in series. If shade falls on one series of cells, you can lose one-third of that panel’s production.
In contrast, a panel made of half-cut cells would have 120 half-cut cells, wired in series/parallel with two strings of 60 cells. Shade that falls on one string would not affect the output of the other, which minimizes production loss caused by shading issues.
Bifacial Solar Panels
Bifacial solar panels are panels that are treated with conductive material on both sides. They’re designed to take advantage of reflected sunlight that hits the backside of the panel.
In theory, this sounds like a great idea because you are doubling the conductive surface area of the panel. But in practice, bifacial panels call for a much more expensive mounting setup to get any real benefits from the technology.
The system needs to be mounted in an elevated position so that there is clearance below the array. It also calls for the right reflective material beneath your array, like white rocks below a ground mount or a white roof.
Bifacial panels are significantly more expensive to install, and at this point, the minor efficiency gains don’t do enough to recoup the extra installation costs. Bifacial panels aren’t quite ready for the limelight, though that may change as the technology develops further.
Which Panels Should I Choose For My Project?
You might be feeling some information overload right now. It’s nice to understand the nuances of the manufacturing process, but ultimately there’s one question on everyone’s mind: “which one should I buy?”
Our advice is always this: look at cost-per-watt and go from there.
To make a fair comparison between products, divide the panel cost by its rated wattage. The result tells you how much power you will generate per dollar you spend. For example:
Going with Mission Solar would mean fewer panels in your array, but the overall system will cost more due to the higher cost-per-watt on the panels. (Both of these are mono solar panels. In this case, the price difference is because Mission Solar panels are made in America and Astronergy is imported from overseas.)
Once you evaluate pricing on a level playing field, then consider whether other factors (like cell technology or country of origin) play a factor in your decision.
For more info, check out our free solar panel buying guide.