Bifacial Solar Panels: Advantages and Disadvantages (500 Watt, Frameless)

Georgette Kilgore headshot, wearing 8 Billion Trees shirt with forest in the background.Written by Georgette Kilgore

Solar Panels | March 29, 2024

Drawing showing bifacial solar panels while a person in the corner wonders what are the bifacial solar panels advantages and disadvantages, how do solar panels work, and what's a 500 watt or frameless bifacial solar panel?

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 different 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.

Solar Panels in the backyard.

(Image: SayCheeeeeese9)

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.

Image of bifacial solar panel with green grass in the background.

(Image: Jana30910)

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.

400 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.

Difference between Monofacial PERC and Bifacial PERC+

(Image: National Renewable Energy Laboratory11)

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:

  • 10,649 ÷ 2.5 = 4,259.6 kWh
  • 4,259.6 ÷ 365 days = 11.67 panels

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.

Close-up image of the bifacial solar panel near the parking lot.

(Image: Department of Energy12)

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.

Graph chart about the manufacturer cost between monofacial and bifacial module.

(Image: National Renewable Energy Laboratory11)

You can check the details below:

Disadvantages

  • 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

Advantages

  • 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.

  1. Ensure that the area is flat and clear of any debris that could interfere with the operation of the PV system
  2. 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
  3. 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
  4. Be mindful when fastening any bolts on the modules to be aware of overtightening because of the sensitive nature of the glass
  5. Allow a gap between the panels so any heavy snow will fall through and not accumulate between them.
  6. 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
  7. 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.

Graphic image about bifacial solar panel irradiance.

(Image: National Renewable Energy Laboratory11)

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.

Frequently Asked Questions About Bifacial Solar Panels

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 More 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.


References

1Solar Energy Technologies Office. (2023). Solar Photovoltaic Cell Basics. Office of ENERGY EFFICIENCY & RENEWABLE ENERGY. Retrieved May 19, 2023, from <https://www.energy.gov/eere/solar/solar-photovoltaic-cell-basics>

2University of California Regents. (2023). Absorption / reflection of sunlight. UNDERSTANDING GLOBAL CHANGE. Retrieved May 19, 2023, from <https://ugc.berkeley.edu/background-content/reflection-absorption-sunlight/>

3University of Wisconsin-Stevens Point. (2023). Unit 1: Exploring Renewable Energy. Renewable Energy Education. Retrieved May 19, 2023, from <https://www3.uwsp.edu/cnr-ap/KEEP/nres635/Pages/Unit1/Section-B-Off-grid-and-Grid-intertied-Systems.aspx>

4Friedlander, B. (2023, March 9). Returning solar panel production to US eases climate change. CORNELL CHRONICLE. Retrieved May 19, 2023, from <https://news.cornell.edu/stories/2023/03/returning-solar-panel-production-us-eases-climate-change>

5Morris, J. (2023, February 2). Renewable Energy. Climate Portal. Retrieved May 19, 2023, from <https://climate.mit.edu/explainers/renewable-energy>

6CONNIFF, R. (2021, November 22). Why Putting Solar Canopies on Parking Lots Is a Smart Green Move. YaleEnvironment360. Retrieved May 19, 2023, from <https://e360.yale.edu/features/putting-solar-panels-atop-parking-lots-a-green-energy-solution>

7Coastal Systems Group. (2023). Solar Irradiation. WOODS HOLE OCEANOGRAPHIC INSTITUTION. Retrieved May 19, 2023, from <https://www2.whoi.edu/site/coastalgroup/about/what-we-study/primers/solar-irradiation/>

8Solar Energy Technologies Office. (2023). Perovskite Solar Cells. Office of ENERGY EFFICIENCY & RENEWABLE ENERGY. Retrieved May 19, 2023, from <https://www.energy.gov/eere/solar/perovskite-solar-cells>

9Exeter High School solar panels Photo by SayCheeeeeese / CC0 1.0 Universal Public Domain Dedication. Resized and Changed Format. From Wikimedia Commons <https://commons.wikimedia.org/wiki/File:Exeter_High_School_solar_panels3.jpg>

10PV Plant in Losheim am See Photo by Jana309. Attribution-ShareAlike 4.0 International (CC BY-SA 4.0). Resized and Changed Format. From Wikimedia Commons <https://commons.wikimedia.org/wiki/File:Next2Sun_Anlagenkonzept.jpg>

11Ilustrations from the National Renewable Energy Laboratory. NREL. Retrieved from <https://www.nrel.gov/docs/fy19osti/74090.pdf>

12Photo by U.S. Department of Energy. Office of Scientific and Technical Information. Retrieved from <https://www.osti.gov/servlets/purl/1457936>