Should you install bifacial solar panels on tracking systems?
Solar trackers promise greater energy yield than their fixed-tilt counterparts because they keep modules constantly pointed toward the sun throughout the day. Similarly, bifacial modules can produce more power than their one-sided solar panel cousins because they have double the exposure level.
A dual-axis tracker from Mechatron Solar was installed using bifacial modules. Stephen Mildenberger
So, is there a benefit to pairing two technologies that each ensure greater solar yield? Some tracker manufacturers believe there is. At the very least, bifacial modules will generate more energy than their frontside power rating. When combined with certain environmental and design conditions, backside generation can be boosted even more.
Bifacial cells made up 50% of the world market share of solar cells in 2021, and that percentage is expected to increase to 85% by 2023, according to the International Technology Roadmap for Photovoltaics. Additionally, tracker manufacturers reported that the large majority of recent solar projects using their tracking systems include bifacial panels.
Besides the benefit of extra backside generation, the bifacial exemption from Section 201 trade tariffs has likely contributed to the technology’s proliferation in the market. But tracker manufacturers aren’t all in agreement on how to prioritize backside optimization.
“Your mileage may vary, and you need to do the math and figure out what’s best for a given project,” said Matt Kesler, director of solar technology at OMCO Solar. “The extra production that you get from bifacial is usually a good investment.”
Rotating solar irradiance on one axis
Single-axis trackers have quickly become a standard in utility-scale solar projects. They can be installed in similar project footprints to fixed-tilt racking, with the added production bonus of row-by-row movement to track the sun throughout the day.
The mechanisms that drive solar trackers and the controls that optimize positioning for energy generation and weather conditions vary by product. Manufacturers often develop in-house control software to accompany their trackers, but directing that software to FOCUS bifacial arrays on backside generation isn’t necessarily the best move.
Array Technologies, a global manufacturer of single-axis trackers, tested optimizing backside irradiance gain with its proprietary control software SmarTrack. During the test and accompanying simulations, the company found that the energy difference between an array running typically and one focusing on backside generation was just 0.1% over a year.
Array found that the system moved erratically, rotating up and down almost hourly to encourage backside rather than frontside generation gains. The backs of bifacial modules are not as efficient as the front, so Array believes the FOCUS should remain on frontside optimization.
“It’s always beneficial to try to maximize the irradiance from the sky with the front side,” said Kyumin Lee, VP of engineering for research and technology at Array Technologies. “That’s the best approach, because if you try to improve backside irradiance but lose on the front side irradiance, you will probably not see any gains, or you would likely run into scenarios where you actually lose energy.”
Credit: Array Technologies
Like system controls, designs for single-axis solar projects with bifacial panels can remain the same as monofacial projects. Ground albedo (or reflectiveness) can be increased with larger row spacing between trackers, meaning there will be less shadowing and more reflected irradiance.
However, increasing row spacing to encourage higher albedo will increase the overall footprint of a solar project.
“Between tracker and tracker, if you have a larger row spacing, there’s more ground that can reflect light. So, yes, you can have higher bifacial gain, but I think my argument there was always that at the end, it’s not bifacial gain that’s paying the bills,” Lee said. “It’s the total energy produced.”
In many cases, bifacial generation should be treated as unexpected bonus gains. Additional energy generated from the back with larger row spacing likely will not account for the cost of the larger land mass used to accommodate it.
White surfaces like snow and crushed limestone can increase ground albedo — snowfall happens naturally, but the latter requires additional site preparations and capital.
Then there’s the design of the tracker structure itself. Array’s DuraTrack HZ v3 installs modules in one-in-portrait orientation. It uses a “high-rise” bifacial module clamp that clears the panel’s junction boxes and includes additional spacing between the back of the module and the torque tube (the pipe that rotates the panel row) compared to its other clamp models.
Array tested how the torque tube affected backside shading on portrait-oriented bifacial modules and found it had little effect on generation.
“There are much larger contributing factors to how the PV plant produces energy related to a bifacial module, such as view factor and then things that are a little bit out of control, like the albedo,” said Cody Norman, director of applications engineering at Array Technologies.
National solar racking and tracking manufacturer OMCO Solar had a different take on the effects of shading caused by torque tubes. The company produces OMCO Origin Factory-Direct Trackers, which have a two-in-landscape panel orientation with a torque tube that runs between the bifacial modules rather than behind them.
The company’s strategy is supported by a 2019 study by the National Renewable Energy Laboratory, Sandia National Laboratories and Cypress Creek Renewables that found torque tube shading reduced backside generation on bifacial modules from 2 to 8%. In individual tests, OMCO found the shading effect was greater than reported.
“Even though the average irradiance is reduced by 8%, the irradiance on some of those cells is reduced by more than 20%,” OMCO’s Kesler said. “Since the cells are in a series, you can’t put more current through some of the cells and less through the others. You can only put the same amount of current through all the cells. If you pull down a few of the cells by more than 20%, you’re pulling down the whole backside by more than 20%.”
Single-axis solar tracker choice and project design is left to the discretion of the system owner. Bifacial backside generation is a given on these projects, but certain design choices made to encourage additional generation can have the tradeoff of reducing frontside generation.
Double-sided cells on dual-axis trackers
Dual-axis trackers pivot on two points, making them able to directly track the sun throughout the day, unlike single-axis trackers that pivot on one.
Dual-axis trackers are installed atop single posts and can hold upwards of 20 panels per unit. These systems are typically deployed in commercial and residential settings and stand taller than single-axis trackers. That greater distance from the ground has proven beneficial for bifacial modules.
AllEarth Renewables, a dual-axis tracker manufacturer, partnered with Sandia National Laboratories to study how bifacial modules performed on trackers in the northern United States, specifically in Vermont where the company is based. The two-year study resulted in a report that found bifacial modules outperformed monofacial modules installed on the same dual-axis tracker at an average of 14% annually. During winter months, that number leapt to 40% because of the high albedo of snow cover.
Ground cover like snowfall creates a higher albedo than other natural surfaces, which can result in higher backside gains for bifacial modules. Stephen Mildenberger
“So far, our data is matching what the predictions are — that we’re getting pretty darn good production in our environments up here,” said David Blittersdorf, president and CEO of AllEarth Renewables.
Dual-axis trackers are often installed in northern states because they can adapt to the territory’s terrain and annual snowfall. Another benefit the study found during winter months was quicker snowshed because of the motion of dual-axis trackers and the translucency of double-glassed bifacial modules.
Due to their height and greater spacing compared to single-axis trackers, more radiant light surrounds dual-axis trackers, leading to more opportunities for backside generation with bifacial modules.
Mechatron Solar, a dual-axis tracker manufacturer, uses table-level reflectors on its M18KD tracker to direct light to the backs of bifacial modules. The company reported a 13 to 15% boost in gains using the reflector instead of conventional ground cover in Northern California.
“We recognized not only that [bifacial] technology is breakthrough, but also that the dual-axis mechanism would achieve higher bifacial boost than either fixed-tilt or single-axis trackers, since our dual-axis follows the sun across both zenith and azimuth axes, unlike the competition,” said Michael Fakukakis, CEO of Mechatron Solar.
Regardless of the structure, there is extra solar production to be gained from using bifacial modules on solar trackers. Weighing the cost and design considerations can help contractors decide when the combination is a good fit.
About The Author
Billy Ludt
Billy Ludt is senior editor of Solar Power World and currently covers topics on mounting, installation and business issues.
Комментарии и мнения владельцев
The main issue with bi-facial panels on a tracker is that the support should not cover the cells on the back. Any cable, or metal pipe will create a shadows ruining the effort of producing electricity from this side. I have tried to design the cheapest tracker possible here youtu.be/uGfn9DSRMd0 but would love to see if it’s possible to get one with no support on the backside. Let me know if you could help pointing me on such project. thanks
Study placing 2 sided solar panels vertical to the sun with mirrors attached at the bottom to the of the panel reflecting back on each side. I think the spacing of spacing of panels would be less and exposure to both sides far more efficient when using trackers.
The AllEarth dual-axis trackers may only support 20 panels, but the Mechatron Solar dual-axis trackers support 90, at a much higher table elevation, thus with much higher bifacial boost. Very big difference in yield.
Bifacial Solar Panels: Advantages and Disadvantages (500 Watt, Frameless)
Are the new bifacial solar panels about to eclipse traditional solar panels?
Many people argue that they might. But they also wonder, how do these differnt types of solar panels work? Do the advantages of bifacial solar panels overcome their disadvantages? And, what’s the difference in frameless and watt rating?
Researchers are constantly improving monofacial solar panels so that they can increase the amount of energy absorbed without increasing the size of the panel. Incremental advances have been made in this department but there’s only so much energy that can be produced from the same-sized package.
Utilizing both sides of the solar panel could be the solution.
Understanding how solar panels work and specifically how bifacial solar panels can enhance the performance can help you decide when purchasing a solar energy system to install.
This guide explains what you need to know.
How Do Solar Panels Work? (Solar Panels Definition)
Solar energy systems are generally manufactured from multiple wafer-thin layers of silicon cells connected together by electrical wiring.
They are then encased in a metal frame to form a panel with a glass or plexiglass front face that has a specific anti-reflective coating on it.
These individual panels are then connected together to form arrays and installed on rooftops or in sizable outdoor spaces so they can be angled toward the sun to maximize solar absorption.
During daylight hours, the solar cells, which are also known as photovoltaic cells, absorb and convert sunlight, commonly referred to as electromagnetic radiation.
into electrical energy by the use of an inverter.
An inverter is required to transform the direct current (DC) electricity produced by the solar cells in your panels into usable alternating current (AC) electricity suitable for household use.
Excess electricity that is not immediately consumed is then stored in a battery storage system.
The number of panels in the arrays will depend on the energy requirements of the premises, and sometimes the space available for installation.
The national average of the panels required to supply sufficient electricity to cater to all a household’s needs is between 17-21 panels, but not all rooftops can accommodate that quantity due to limited space.
The size of standard solar panel for residential properties is 5.4 feet by 3.25 feet, and weigh about 40 pounds each. When there are up to 21 of them arranged in an array a considerable amount of space would be needed.
Under any form of space restrictions, options are limited to either installing other arrays on another part of the property or installing larger, more powerful solar panels that will still have space constraints.
These types of solar panels are classed as being monofacial and the basics of how they function rely on the front face of the panel, 1 where solar radiation is absorbed, directly facing toward the sun for the majority of the day.
This is often achieved through a tracking system that moves and angles the modules on a predetermined setting based on the sun’s movement across the sky.
Bifacial solar panels can do that and more.
What Are Bifacial Solar Panels? (Bifacial vs Monofacial Solar Panels)
Bifacial solar panels use identical silicon-based solar cells to monofacial solar panels.
There is no difference there.
They are both manufactured either from monocrystalline or polycrystalline cells, with the former being more expensive but more efficient at energy capture and conversion.
Monofacial solar panels, however, have one glaring fault that bifacial panels resolve quite cleverly, and that difference enables the bifacial solar panel’s efficiency level to be greater by 15% to 30%.
This increase in efficiency is because the majority of solar panels in use today only collect light and transform it into electricity when they are pointing toward the sun. They are effective to a large degree but a significant percentage of invisible light rays pass through the cells without being absorbed and are wasted.
Researchers behind the bifacial technology examined methods of harnessing those invisible rays and redirecting them back into the cells. They reasoned that if the unused underside of a solar panel could convert those uncaptured infrared rays that more electricity might be produced.
So, rather than having an opaque back plate, bifacial panels have a reflective material on the back that not only redirects any light that passes through the sun-facing monocrystalline cells but absorbs any light refracted from the ground, converting it into energy.
Although most of the sunlight is still absorbed by the panel’s front, some bifacial PV systems can produce up to 30% more energy since they expose both sides of the solar cells to sunlight.
Frameless Bifacial Solar Panels
Another primary difference between bifacial and monofacial panels is the framing.
The traditional framing for solar arrays is composed of aluminum, a material that has been used for decades due to its durability and lightness.
There are many consumers that simply do not like the image presented when silver-framed panels are installed on their rooftops, deeming them unsightly.
Bifacial solar panels keep the solar cells in place with two panes of glass and a reflective back plate and are often frameless.
This design allows them to be fully transparent and have a more exposed surface area, enabling the solar cells to capture more sunlight from both the front and the back. 2
Still, many neighborhood HOAs are against unsightly rooftop solar arrays, actively campaigning against anyone installing them despite the benefits to the homeowner and the planet.
Bifacial arrays are more pleasing to the eye aesthetically when rooftop mounted, yet they are more effective when placed next to highly reflecting surfaces that can bounce light back onto the underside of the panels.
This can be installing bifacial solar panels on roof that are flat, in ground-mounted locations, on pergolas, or on lean-tos to replace the actual wooden roof slats themselves.
As long as the ground underneath has reflective properties the bifacial panels will absorb more light and produce more electricity than monofacial arrays.
This creates an advantage of bifacial solar panels vs monocrystalline panels that have only one absorbing face.
If a bifacial panel can generate more energy than a typical solar panel it would mean that less of them would be required to fully power an average household, which would result in less space requirements.
0 and 500-Watt Bifacial Solar Panels vs 500-Watt Monofacial Solar Panels
Several manufacturers have started to offer 500-watt solar panels to residential premises in an effort to boost the output without claiming more real estate which is often a barrier to new clients with space restrictions.
(Image: National Renewable Energy Laboratory 11 )
Under ideal conditions, these larger panels will be able to generate more electricity on a daily basis than smaller wattage panels. On average, 2 kWh would be produced from each panel, and approximately 14-15 of them would be sufficient for an average residence rather than the 17-21 required to power a house now.
Related Reading : How Many Solar Panels to Power a House (For Every Size, Type, Location)
Unfortunately, the size and weight are increased, with an additional 30 pounds and a new size of 7.40 feet by 3.72 feet, but the configuration is smaller which makes the PV arrays more convenient to a wider consumer base.
500-watt bifacial solar panels are fractionally smaller, yet slightly heavier due to the extra glass layer, but will have a greater energy output of between 15% to 30% determined by the local conditions.
A total of 15 monofacial panels produce 2 kWh per day each, producing 30 kWh a day, 840 kWh a month, and 10,080 kWh a year.
A standard residential property needs 10,649 kWh a year to function independently from the local grid systems. 3
If the average increase in energy output from a bifacial solar panel is 25%, that would mean an additional 0.5kWh per day per panel. Although that may not seem significant, it has the possibility to augment the overall electricity production, reduce the number of panels installed, and save money.
Dividing the average residential property yearly kWh consumption of 10,649 by 2.5 would reveal a result of:
So instead of having to install 15 panels within the array, it would be possible to reduce that amount to 12 and still have the same amount of energy production.
Where this space-saving option would come into play if other energy dependant products, such as an electric car, were to be added to the system, which would require another 5 to 12 panels.
If the 500-watt panels are too big then the 400-watt bifacial solar panels could be used instead with equally impressive results.
Industrial Bifacial Solar Panels
Commercial industries are also examining the benefits that bifacial solar panels can bring to their bottom line.
(Image: Department of Energy 12 )
Some of these business owners may be concerned with climate change, but if they are in an industry that is energy-intensive, any option that can reduce those overheads has to be considered.
A brief glance at a solar panel size chart immediately shows the discrepancies in sizes between industrial solar panels and residential ones.
Compared to industrial solar panels, household solar panels are typically smaller and provide less power, and produce 300 to 400 watts of power per panel, occasionally 500 watts.
They are made to be set up in small-scale ground installations or on rooftops of homes to produce enough electricity to power an average family. These solar panels typically produce 300 to 400 watts of power per panel.
Industrial solar panels are bigger and provide more power, 700 watts per panel or more, and are installed in larger commercial business premises.
Solar farms are where the largest panels are used to maximize energy production and the land space available.
It would be a major achievement for a business of this type to be able to replace all of its conventional panels with ones that can absorb light from both faces and increase their energy production, the extra energy that they can then sell back to the grid for increased returns on their investments.
It’s no wonder that bifacial solar panels are becoming extremely popular for industrial-sized operations across the United States interested in saving money and mitigating climate change. 4
Bifacial Solar Panels Advantages and Disadvantages
There are pros and cons associated with bifacial solar panels, as with most things, but the advantages far outweigh the disadvantages.
(Image: National Renewable Energy Laboratory 11 )
You can check the details below:
- Extra power comes with extra cost and bifacial solar panels generally cost at least 10% more than conventional panels
- Installation is also more complicated, requiring special equipment due to the additional weight of the extra glass sheet per panel
- The mounting structure is unique to the array format and cannot be interchanged between all types of other PV arrays
- Installing them over grass or dirt would negate the advantage of the second face as no light would be reflected
- Owing to the greater energy output fewer solar modules are required
- Even when the intensity of the light is reduced towards the end of the day or not directly facing the panels, more light is absorbed compared to monofacial panels
- Any diffused light reflected from nearby surfaces can be absorbed
- The tempered glass-to-glass composition enhances the durability and longevity of the modules
- There is a lower risk of degradation due to the improved production process and manufacturers are confident in issuing 30-year warranties
- There is a lower risk of corrosion and microcracking.
- Bifacial solar arrays are more pleasing to the eye whether placed on flat roofs or especially on angled lean-tos where they can become a charming feature
- They will function more efficiently than monofacial panels when covered in snow because the second face will still be absorbing light
- Whereas conventional panels work best at angles of 35° and 45°, bifacial panels can even be erected at 90° for maximum exposure to the sun from virtually all angles
How To Install Bifacial Solar Panels
Employing a company to install your newly purchased bifacial solar panels can be an expensive endeavor, especially if you have the know-how to do it yourself. It is not overly complicated and if you follow these simple steps you can be solar-powered in no time.
Flat roofs are the best options as long as there are no overhead obstructions such as trees or nearby buildings that will cast shadows over the panels.
Ground-mounted installations are more prone to being overshadowed but even if they are not it is important to ensure that the ground beneath them has a reflective surface; grass or dirt would nullify the advantage that bifacial solar panels have.
Pergolas attached to the property can either be another primary or secondary installation for this renewable energy provider if they can hold enough solar panels. 5
Many consumers concentrate solely on one location to install a PV system, but there is no reason why another site couldn’t be used as all wires would lead back to the storage system where the energy from the two sources would be accumulated.
Irrespective of the ultimate site selected for installation, there are a few fundamental steps that need to be adhered to for the two-sided panels to work effectively.
- Ensure that the area is flat and clear of any debris that could interfere with the operation of the PV system
- The racking system has to be positioned at a minimum height of 3-4 feet from the ground to allow sunlight to pass beneath from various angles. Do not install the panels flat onto a sloped roof as this will negate the benefit of having two solar absorbent surfaces
- Position the racking so it, too, doesn’t interfere with any light penetration. New racking solutions use tiny junction boxes, narrower support rails, and vertical supports at the very corners of the racking system to reduce any shadowing beneath the modules
- Be mindful when fastening any bolts on the modules to be aware of overtightening because of the sensitive nature of the glass
- Allow a gap between the panels so any heavy snow will fall through and not accumulate between them.
- If the surface is non-reflective or dark-colored, consider applying a white, reflective material, such as paint or an EPDM material on the ground
- Connect to the inverter and then the local grid using the supplied solar panel connector types
Bifacial Solar Panels Advantages With Installations
Apart from the option of installing solar panels in two separate locations on a single property, another possibility often disregarded is taking advantage of available water surfaces like a lake or other bodies of water.
By the use of a floating racking system, the second face of bifacial solar panels will benefit enormously from the incredible reflective nature that can be achieved from the water’s surface.
The body of water does not have to be large to amplify the energy generated from the PV system, but the increase in electrical output will be noticeable.
In fact, bifacial panels can be a good solution if employed on any free-standing structures as long as the ground beneath will reflect sunlight back up to the under-face panels, 6 and awnings, pergolas of all shapes, and canopies are becoming popular choices.
Interesting Facts About Bifacial Solar Panels
Every new technological advancement appears to have been developed quickly, talked about one minute, and brought to market the next.
(Image: National Renewable Energy Laboratory 11 )
Rear-side irradiation is no different. Developers within the industry know differently, more than aware of the backstory to new technologies.
What other interesting unknown facts are there about these two-faced panels?
- The first demonstration of the effectiveness of bifacial solar cells was in space. In 1974, the Salyut 3 in the Soviet Space program conducted an experiment that proved the superior energy generation properties over monofacial panels
- Patents were filed in 1976, and 1977 by a renowned Spanish scientist, Antonio Luque Lopez, who is recognized as the inventor of the bifacial solar cell used today
- In 1997, SunPower produced a prototype that showed a lot of commercial promise, but it never saw the light of day, and interest died down for the next few years
- Incremental technological advances over the next decade culminated with the company, Yingli, a Chinese PV producer, selling the much-improved bifacial solar cells in 2012
- Another decade later and the bifacial solar cell market accounts for over a 20% share of the PV industry
With decades in the making, the advantages of bifacial solar panels over monofacial panels are numerous.
They can be installed in similar locations to traditional panels but with an increased solar irradiation absorption capacity. 7 This results in higher energy levels delivered to both residential and commercial premises and a reduction in utility bills.
There can be no question that bifacial solar panels: advantages and disadvantages – 500 Watt, 400, frameless – are going to be around for a long time.
Are Bifacial Panels Suitable for Rooftops?
Sloping roofs are not suitable. To reap the benefits of bifacial solar panels, they need to be positioned no more than 13 feet from the ground or from a flat surface to better capture the refracted light rays.
What Is the Cost of Leasing Solar Panels?
After a down payment to the leasing company, the cost of leasing solar panels can be between 50 to 250 per month depending on energy requirements.
Where Are the Best Places to Mount Bifacial Solar Panels?
A raised platform with a minimum height of 3-4 feet that has full sun exposure is ideal, especially if the ground beneath is reflective.
Can Bsps Be Installed on Sloped Roofs?
As long as the panels are not installed flush with the tiles, they can still be effective on an angled rooftop.
How Long Do Bifacial Panels Last?
Manufacturers are giving 30-year warranties with the expected lifespan of these specific types of solar panels estimated to be around 50 years plus.
Are There Bifacial Panels Expensive?
Generally, BSPs are more expensive to purchase and install. However, the Biden administration has exempted this new sector from import tariffs for U.S. developers to make them competitive in the marketplace against monofacial panels.
What Incentive Programs Are There?
Incentive programs are available on a federal, state, and local level to reduce the purchase and installation costs to homeowners and business owners to save money and adopt solar energy.
Are Perovskite Solar Cells Better Than Silicon?
These hybrid organic-inorganic cells are potentially revolutionary since they have the potential to lower production costs and, 8 just as importantly, increase output. Combining them with bifacial solar panels could revolutionize the industry.
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References
1 Solar Energy Technologies Office. (2023). Solar Photovoltaic Cell Basics. Office of ENERGY EFFICIENCY RENEWABLE ENERGY. Retrieved May 19, 2023, from
2 University of California Regents. (2023). Absorption / reflection of sunlight. UNDERSTANDING GLOBAL CHANGE. Retrieved May 19, 2023, from
3 University of Wisconsin-Stevens Point. (2023). Unit 1: Exploring Renewable Energy. Renewable Energy Education. Retrieved May 19, 2023, from
4 Friedlander, B. (2023, March 9). Returning solar panel production to US eases climate change. CORNELL CHRONICLE. Retrieved May 19, 2023, from
5 Morris, J. (2023, February 2). Renewable Energy. Climate Portal. Retrieved May 19, 2023, from
6 CONNIFF, R. (2021, November 22). Why Putting Solar Canopies on Parking Lots Is a Smart Green Move. YaleEnvironment360. Retrieved May 19, 2023, from
7 Coastal Systems Group. (2023). Solar Irradiation. WOODS HOLE OCEANOGRAPHIC INSTITUTION. Retrieved May 19, 2023, from
8 Solar Energy Technologies Office. (2023). Perovskite Solar Cells. Office of ENERGY EFFICIENCY RENEWABLE ENERGY. Retrieved May 19, 2023, from
10 Jana309. Attribution-ShareAlike 4.0 International (CC BY-SA 4.0). Changed Format, Resized. Wikipedia Commons. Retrieved from
11 National Renewable Energy Laboratory. NREL. Retrieved from
12 Department of Energy. Office of Scientific and Technical Information. Retrieved from
How MPPT Technology is Shining New Light on Bifacial Solar Panels
The global demand for bifacial solar panels, panels that produce solar energy from both sides, is growing massively, with market share predicted to reach 35% of all global solar energy installations by 2030. This is largely because bifacial solar panels not only produce more energy, but they have also become significantly more cost effective.
If the goal of a PV system is to have the lowest Levelized Cost of Energy (LCOE, the cost of solar power production divided by the lifetime energy production of the solar project), then consider that an optimally placed PV system with bifacial panels can result in 10-15% lower LCOE, resulting in higher return on investment.
What is a bifacial solar panel and how does it work?
Bifacial solar panels are panels that convert PV energy from the front and back sides of the module, as opposed to the traditional ‘monofacial’ panels that produce on one side only. With monofacial solar panels, the front is comprised of photovoltaic cells (made up of semiconductors), while the back side is protected by a backing sheet. Bifacial panels utilize photovoltaic cells on both the front and rear. This enables power production also on the back side, increasing the amount of energy that can be produced by around 6-10% or more in some cases 1
Which types of PV Systems work best with bifacial modules?
It’s important to bear in mind that bifacial modules may not be suitable for all installations, but best suited for tilted systems and areas with high surface albedo. Some examples of this would be areas with white concrete, snow and ice, desert sand, or water. Bifacial modules may produce more energy when installed in optimized conditions.
Why SolarEdge inverters are best for bifacial modules
While using bifacial solar panels can yield more energy, it also brings more complexities. Installing SolarEdge’s Smart PV solutions in a bifacial system solves many of these complexities and improves the system LCOE.
As with monofacial panels, bifacial panels can experience module mismatch causing potential power losses and dragging down the overall system’s performance. This is common in all types of solar panels; however bifacial panels are even more susceptible to module mismatch because the light that hits the rear side is less uniform than the front. There are several reasons for this:
- Inconsistent surface underneath the modules (from uneven snow or glass, different soil or material conditions, and more)
- Different angles of the sun or shading by other modules and racking
- Irradiance differences between modules located at the edge of the rows and in the middle, often called “edge effects”
- Higher module degradation, ripples in floating PV, foliage growth in ground mount systems, and more
Installing a SolarEdge system with bifacial modules is optimal for maximum energy yield and faster return on investment (ROI). The SolarEdge solution utilizes Maximum Power Point Tracking technology (MPPT) that comprises a Smart inverter with Power Optimizers connected to panels in 2:1 configuration in commercial installations. In traditional PV systems, even if one module produces less energy due to mismatch, production of the entire string is lowered accordingly. With the SolarEdge’s DC optimized topology, these power losses caused by mismatch between modules are mitigated, resulting in maximum power generation from each individual module.
How MPPT Technology is Shining New Light on Bifacial Solar Panels
The global demand for bifacial solar panels, panels that produce solar energy from both sides, is growing massively, with market share predicted to reach 35% of all global solar energy installations by 2030. This is largely because bifacial solar panels not only produce more energy, but they have also become significantly more cost effective.
If the goal of a PV system is to have the lowest Levelized Cost of Energy (LCOE, the cost of solar power production divided by the lifetime energy production of the solar project), then consider that an optimally placed PV system with bifacial panels can result in 10-15% lower LCOE, resulting in higher return on investment.
What is a bifacial solar panel and how does it work?
Bifacial solar panels are panels that convert PV energy from the front and back sides of the module, as opposed to the traditional ‘monofacial’ panels that produce on one side only. With monofacial solar panels, the front is comprised of photovoltaic cells (made up of semiconductors), while the back side is protected by a backing sheet. Bifacial panels utilize photovoltaic cells on both the front and rear. This enables power production also on the back side, increasing the amount of energy that can be produced by around 6-10% or more in some cases 1
Which types of PV Systems work best with bifacial modules?
It’s important to bear in mind that bifacial modules may not be suitable for all installations, but best suited for tilted systems and areas with high surface albedo. Some examples of this would be areas with white concrete, snow and ice, desert sand, or water. Bifacial modules may produce more energy when installed in optimized conditions.
Why SolarEdge inverters are best for bifacial modules
While using bifacial solar panels can yield more energy, it also brings more complexities. Installing SolarEdge’s Smart PV solutions in a bifacial system solves many of these complexities and improves the system LCOE.
As with monofacial panels, bifacial panels can experience module mismatch causing potential power losses and dragging down the overall system’s performance. This is common in all types of solar panels; however bifacial panels are even more susceptible to module mismatch because the light that hits the rear side is less uniform than the front. There are several reasons for this:
- Inconsistent surface underneath the modules (from uneven snow or glass, different soil or material conditions, and more)
- Different angles of the sun or shading by other modules and racking
- Irradiance differences between modules located at the edge of the rows and in the middle, often called “edge effects”
- Higher module degradation, ripples in floating PV, foliage growth in ground mount systems, and more
Installing a SolarEdge system with bifacial modules is optimal for maximum energy yield and faster return on investment (ROI). The SolarEdge solution utilizes Maximum Power Point Tracking technology (MPPT) that comprises a Smart inverter with Power Optimizers connected to panels in 2:1 configuration in commercial installations. In traditional PV systems, even if one module produces less energy due to mismatch, production of the entire string is lowered accordingly. With the SolarEdge’s DC optimized topology, these power losses caused by mismatch between modules are mitigated, resulting in maximum power generation from each individual module.
Because each panel performs individually, this enables more flexibility in the design of the system, including installing more panels at different angles or with inconsistent shading, as often occurs with bifacial panels. Using SolarEdge inverters and Power Optimizers eliminates these power losses.
Additionally, bifacial modules must be mounted on a higher racking system in order to expose the back to reflective sunlight. But with SolarEdge’s design flexibility, modules connected to SolarEdge Power Optimizers can be mounted at any angle, tilt, or orientation while still producing more energy. The extra energy produced over the system’s lifetime equates to better LCOE and a measurable increase in ROI.
In several sites with bifacial panels, the SolarEdge Monitoring Platform has shown that SolarEdge’s commercial PV solutions provided 4-7% more energy than initially expected from the PVsyst models, as shown in the chart below:
Powering the largest PV system in rural Alaska
Kotzebue, Alaska has snow over 60% of the year, so when it came time to select the panels for their 576kW ground mount PV system, bifacial modules coupled with SolarEdge’s three-phase inverters with Synergy Technology and Power Optimizers were a great fit. SolarEdge’s Smart PV solution was ideal for this project for several reasons. SolarEdge’s DC optimized commercial solution eliminated mismatch losses by almost 3% in the first year compared to a traditional string inverter. In addition, the energy gain is estimated to be over 6% by year 20, due to module degradation according to PVsyst modeling. By pairing SolarEdge’s inverter and Power Optimizer combination with bifacial modules, an additional gain of at least 5% is expected. Another added benefit is that the Kotzebue Electric Association can remotely troubleshoot through the SolarEdge Monitoring Platform, further reducing onsite visits and maintenance and lowering their OM costs.
The Path to Making Bifacial Shine
Solar power could provide a quarter of global electricity needs by 2050, but for that to happen global capacity must reach 18 times current levels. That is why bifacial modules are so critical, with some manufacturers and industry analysts predicting they will eventually overtake mono-facials as the go-to technology, especially in ground mount solar installations. The key to worldwide adoption ultimately depends on the ability to overcome module-mismatch that is common in bifacial modules to extract the maximum energy production airing bifacial solar panels with SolarEdge’s DC optimized commercial PV solution can yield more energy, and lead to an overall higher return on investment and lower Levelized Cost of Energy
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We’ve come a long way since ancient Greek homes were kept toasty using passive solar heating and since the Romans warmed their bathhouse water from the sun. New customer needs, innovative new products, and exciting new inventions are being put to use to harvest energy from the world’s most powerful energy source. So, as this year gets underway, let’s look at some of the exciting renewable energy trends that we can look forward to seeing more of in 2023. 1. The Rise of the Prosumer – and Energy Management “Prosumers”, as envisaged by Alvin Toffler in his 1980 book The Third Wave, are consumers who take an active part in the process of production. Indeed, homeowners and business owners with a PV installation, are active prosumers – who produce some or all of their own electricity and even sell it back to the grid. With the growing popularity of PV as a renewable energy source, coupled with the increased cost of electricity, this growing group of prosumers require additional tools in order to maximize the options available to them. As PV adoption grows, optimizing its use becomes even more critical. The prosumer has many decisions to make on a daily, hourly or even minute-by-minute basis: should I store my PV for later or use it now? When is it most efficient to run the washer/dryer– or for a factory owner, how can I take best advantage of my on-site solar production to power my manufacturing line? Should I charge my electric car with solar power? When? Enter stage left, energy management. PV is designed to provide its owner with financial benefits, as well as sustainable alternatives. But system owners have more pressing things to do with their time than program and monitor their home energy around the clock. These operational decisions should be able to be made automatically with minimum attention required from the PV system owner in order to optimally take advantage of their PV production. Fortunately, SolarEdge has built Smart energy management into SolarEdge Home, the SolarEdge residential solution. As an integral part of our Smart energy ecosystem, Smart energy management is easy to deploy. Homeowners utilize load controllers to manage essential loads (specific appliances that need to remain powered on), select their preferences, while the SolarEdge Home Operating System orchestrates the home’s energy automatically. Homeowners monitor performance through the mySolarEdge app and can make changes if required. SolarEdge makes becoming a prosumer particularly lucrative for users. 2. Community and Multi-dwelling PV Installations Community solar is an exciting renewable energy trend that is growing in popularity and in applications. According to the U.S. Department of Energy, community solar is defined as “any solar project or purchasing program, within a geographic area, in which the benefits of a solar project flow to multiple customers such as individuals, businesses, nonprofits, and other groups.” These types of projects provide solar energy access to individuals or businesses that could not otherwise harvest their own solar energy. The beauty of these installations is that they accelerate solar energy adoption and decarbonization in a region, while democratizing the process, making solar energy accessible to everyone. Here are some interesting community solar stories: Puerto Rico – An ambitious community solar project that is also exciting because of the significant quality of life improvement it offers. Puerto Ricans have been subjected to deadly hurricanes which have repeatedly knocked out their access to electricity, especially when they needed it most. Even in the best of weather conditions, their power grid is frequently thwarted by repeated outages which leave residents without electricity. In response, many Puerto Ricans have been installing solar solutions. And now, 7,000 of those installations will be connected to form the US territory’s first virtual solar virtual power plant (VPP). This will provide power and stability to Puerto Ricans who aren’t able to install their own PV. Working together with utility companies, the aim is to reduce reliance on the fossil fuel operated “peaker” plants that are accessed when there is high demand – and enable more residents on the island to benefit from solar. Africa – Many areas in Africa did not have access to energy at all prior to the availability of solar. A number of initiatives led by partner organizations that include the World Bank, SNV Not for Profit and others have created mini-grids in areas not previously connected to solar, with pay-as-you-go and other plans to ensure accessibility for impoverished residents. To date, more than 32 million Africans have access to basic electricity because of projects of this type. This is only a drop in the ocean of the more than 600 million who still are waiting for that access, so there is more work to do. Around the globe Community solar doesn’t only assist in areas of need. The US alone boasts 1600 different community solar projects. 41 US states plus D.C., have at least one community solar project installed, all together, producing 5.3 gigawatts as of Q3 2022. Europe is home to an estimated 10,000 community solar projects. In Germany alone, 900 energy co-ops sell solar to homes and businesses. And this is only the beginning of a trend that is rising, with solutions for individual multi-resident dwellings becoming mainstream. SolarEdge community solar A recent SolarEdge community solar site in the US is the Hartford Pike Project, led by Sunlight General Capital. The project is situated on a 12-acre site in Foster, Rhode Island, on undulating ground that also experiences shading from nearby trees. This is a typical scenario in many of the locations available for community solar, and fortunately, it is not a hindrance with SolarEdge technology. SolarEdge Power Optimizers attach directly to solar modules and enable each module in the string to perform independently at its maximum power point. Underperformance due to shading, for example, will not impact the other modules on the same string, ensuring maximized energy production of the entire system. This technology also afforded Sunlight General Capital precise module level monitoring. As James Pochez, Head of Product Development explains, “To optimize energy production…we needed to be able to monitor all 15,800 solar modules in real-time and ensure we can pinpoint any issues quickly and efficiently. As the owner/operator of this project, the decision on what to build will impact our business for the next 25-years plus. It is in our best interests to choose the best quality solution available.” In its first nine months of operation, the Rhode Island project generated 5.81 GWh of solar energy, of which 3.35 GWh was made available to local residents and businesses through the community solar initiative. 3. Hybrid Hydro and Solar Water and sun. Could it be a marriage made in heaven? Both hydro and solar are renewable energy technologies that help countries around the world reduce their dependence on fossil fuels. Yet the use of each alone includes certain drawbacks. A study undertaken by the European Joint Research Center estimates that covering just 1% of Africa’s hydroelectric reservoirs with solar panels could double their capacity to 58 gigawatts and increase overall generating capacity by up to a quarter. Hydroelectric plants currently generate 90% of the electricity used in several African nations and are significant to the power grid in the US and elsewhere. However, severe drought experienced in many of these same regions, coupled with natural evaporation, is threatening the viability of many of these plants. Due to drought, a hydropower dam in California was shut for several months, and other huge dams reduced production. In one year alone, 2016 to be exact, 42 billion m³ of the hydropower industry’s water evaporated. In tropical locations, up to two meters of water can evaporate from the surface of hydroelectric plants each year – sometimes up to half of the water they capture. Placing solar panels over hydroelectric plants is a viable solution to reduce evaporation, as proven by researchers at the University of California Merced, studying the effects of covering a 4,000-mile water canal with solar panels. They learned that such an installation could save 65 billion gallons of water annually. This renewable energy trend could have huge potential. Adding floating solar panels at these sites is simple, as hydropower plants are already connected to the grid. The synergy of the two technologies makes for a much more stable environment. Solar can compensate for hydropower during dry periods and the two can balance each other out, depending upon the time of day and surges in electricity use. Floating PV provides a higher energy yield because the water is cooler than the earth. Installing panels can also assist with reducing algae growth where it is not welcome. renewable energy trends to come… In a future blog we’ll talk about some other renewable energy trends – like new EV applications, job opportunities around the globe, where solar panels go when they die, and other ways PV is working together with other industries for amazing, complementary results… Stay tuned!
As the impact of climate change continues to disrupt our lives, many governments are looking toward the sun as source of renewable energy. Some, like the United States and Switzerland, are even offering incentives to go solar. And it’s working. According to the International Energy Agency (IEA) Photovoltaic Power Systems Program (PVPS), the rate of PV installations across the world during 2020 was more than double compared to 2016, and more than 7 times compared to 2012. While most companies and homes that go solar do so with the intention of generating as much energy as possible, others consider the aesthetics to be no less important. Design, shape, visibility, and utilization of solar panels (otherwise called photovoltaics or PV panels or solar modules) for additional income such as advertising are some of the considerations. Mickey Mouse, panda bears, and wild horses Take, for example, Disney, which is using PV panels in the shape of Mickey Mouse as part of their brand. In fact, the Disney company is harnessing the power of the sun at four installations across the globe and, according to their estimations, these sites will produce enough energy to power over 65,000 homes for one year. And there is a company in China which invests in and operates PV fields in the shapes of smiling panda bears. In fact, a solar project in China earned a new world record for the largest ever solar panel image – it occupies an area of about 1,400 square meters, the same size as roughly 200 football fields! According to the Dailymail, the project produces power for over a million houses and was built as a part of the government’s effort to promote tourism and energy resources in the Gobi Desert. The image shows the local horse breed that characterizes the region. This all sounds great in principle, but is there a downside? A solar site that is designed in a special shape could potentially enhance a phenomenon known as module mismatch where some modules can produce less power than others. Module mismatch can limit the power production of the stronger modules in the string to that of the weakest modules. However, companies such as Kia, Hyundai, and Audi have designed sites incorporating their logos without compromising on the generated energy. These companies are using SolarEdge Power Optimizers to enable each solar module to generate electricity at its maximum potential. What are solar modules? With many “creative” solar energy solutions still in the early development stages and facing their own engineering challenges, let’s first understand a few basics about PV panels which can be found in our neighborhoods, commercial parks, farms, and even in remote unpopulated deserts, and look at several interesting solutions. First of all, what’s the difference between solar modules, solar panels and PV panels? In most cases, not much. They are all terms that can be used interchangeably depending on region. They are made of silicon, glass and metal and, when exposed to the sun, they produce power. But for all practical purposes, however you refer to them – modules or panels.- each is single unit of a packaged, connected assembly of solar cells, wires, electronics, glass, and a frame. A standard PV panel comprises an array of solar cells with various spacing configurations. The cells are interconnected with metallic conductors and positioned between the front glass and a back sheet. The most common solar cells are made of crystalline silicon that is dark blue in color and is cut into the familiar rectangular shape. The conversion efficiency of these PV cells depends on the spectrum of the irradiance – some frequencies of light are converted better than others. Some PV technologies can also produce power from irradiation that passes through the cells and is reflected by the back sheet into the back side of the cell. It’s worth mentioning that in addition to the standard PV panels, there is another type of solar panel.- bifacial PV panels which are designed to convert radiation from the front and back side of the panel. Bifacial PV panels utilize glass instead of a reflecting back sheet. In this case, the silicon is placed between two glass sheets, allowing radiation to be reflected back from the ground directly on the PV silicon. Let’s get even more creative with solar There are lots of ways to change the overall look of solar panels, some of which are even manufactured in monochromatic red, green, gold, and silver. One of the most popular is to paint the gap between the cells in a dark color, making them look more homogenous. But this does not come without its challenges. Homogeneous colored panels are great for places where the panels are located far from sight. However, sometimes the metallic conductors can be seen through the paint. Some companies eliminate all metallic conductors from the front side of the panel with technologies that enable back contact PV cells, leaving the front of the cells polished and flat. There are also “skins” that can be used with any panels in a process that closely resembles tinting a car’s windshield. Companies even make use of these skins for advertising purposes or blend them in a patterned environment. The main challenge in a painted front surface of a solar panel is that it blocks a portion of the light, negatively impacting the panel’s efficiency and essentially producing less power. Some technologies mitigate the negative effect of paint by using specific colors and materials that allow most of the light to reach the silicone behind them. Another approach is to reduce the amount of paint by painting only small dots while leaving the gaps between the dots completely unpainted instead of painting the entire surface. Getting solar in shape The traditional rectangular-shaped solar modules were designed to address engineering and economic considerations. An important consideration for a solar panel is that most of it be covered with silicon as the gaps between silicon cells and the frame around them are not utilized for producing power. Therefore, solar panel manufacturers increase the portion of the silicon area of their panels by reducing the gaps between cells and the width of the frame. This criterion is sometimes referred to as the “packing factor.” Rectangular cells can be packed better than circular cells. combined with a rectangular frame we get a good packing factor. So, what happens when the installation site is not rectangular? The remaining area is usually left unutilized`. Some manufacturers have begun introducing PV panels in various shapes such as triangles and trapezoids. With more area utilized, more power is subsequently generated. This solution is beneficial for sites with tiled roofs and a non-rectangular shape. There is also a growing niche of curved solar panels which are suitable for curved roofs. The curved surface of the solar panel poses its own problems as different parts of it face different directions. For example, curved solar panels that encircle streetlights face the sun on one side while the other side is shaded, resulting in a mismatch. Some solar panel manufacturers are dividing the curved solar panels into small sections, then electrically grouping sections that face similar directions together. This solution allows curved solar panels to produce power even under significant mismatch conditions. Looking towards the future Solar panel aesthetics are a major consideration that is gaining traction as a growing number of technologies are becoming commercialized. In fact, building-integrated photovoltaics (BIPV) is expected to develop rapidly due to government regulations and polices. This means that more panels will be integrated into new buildings, making the design and aesthetics key characteristics of a solar installation. This rapidly growing market could foster more innovative design concepts that may even become standard. I expect to find more aesthetic PV products in branding, advertisements, rooftops, and large utility fields. If you find any, please let us know in the Комментарии и мнения владельцев.