Everything You Need To Know About Bifacial Solar Panels

Bifacial solar panels are a big step in the evolution of solar panels and are becoming increasingly more accessible and affordable. In recent years, monofacial solar panels have been the industry standard. But now, there’s a new kind of solar panel on the market that’s more efficient than traditional panels. It’s called a bifacial solar panel, and it’s quickly becoming the new standard in solar technology.

This article sets out everything you need to know about monofacial and bifacial solar panels and how making the switch to an EcoFlow bifacial solar panel could be a game-changer for you.

What are Bifacial Solar Panels?

Bifacial solar panels are solar panels that take advantage of the front and the rear side of the panel. While traditional solar panels only use the front side, bifacial solar panels can absorb sunlight from both sides. This makes them more efficient than conventional panels because they can collect more light energy overall. 

What are Monofacial Solar Panels?

Monofacial solar panels are the most common type of solar panel. They only use the front side of the panel to collect sunlight. This makes them less efficient than bifacial solar panels. However, they are still a good option for those looking to use solar power and save on energy bills.

Bifacial vs. Monofacial Technology

The technology used in bifacial and monofacial solar panels is more or less the same. 

You may have heard solar panels called PV panels or PV modules. PV stands for “photovoltaic,” and both monofacial and bifacial solar panels convert photons from sunlight into DC electricity using the photovoltaic effect. 

Solar panels are comprised of photovoltaic materials — typically monocrystalline or polycrystalline silicon. 

Monocrystalline solar cells are made from a single crystal of lab-grown silicon and offer higher efficiency than polycrystalline or thin-film cells. 

Efficiency has two meanings in the context of solar panels. Monocrystalline solar cells are efficient at converting sunlight into DC electricity, and they have an “efficiency rating.” As a solar panel spec, efficiency measures how much available sunlight gets converted into electricity per square meter of photovoltaic material and is expressed as a percentage. 
Essential solar panel specs like efficiency and rated power are determined in a laboratory under Standard Test Conditions. Reputable solar panel manufacturers adhere to the same STCs to level the playing field for consumers.

How Do Monofacial Solar Panels Work?

Monofacial solar panels are the most common residential PV modules on the market today.

On the front of the panel, solar cells are arranged under a transparent protective surface (often tempered glass) and framed in metal. This construction method describes most rigid solar panels — flexible and portable solar panels differ in construction, but all rely on solar cells. 
Solar cells convert sunlight into DC electricity using the photovoltaic effect. The direct current flows through cables to a portable power station, inverter, or another component in the balance of system.

How Do Bifacial Solar Panels Work?

Bifacial solar panels are a relatively new innovation that maximizes the capture of ambient sunlight.

The basic principles remain the same. Solar cells convert the photons in sunlight into direct current (DC) electricity that is transmitted through cables to a balance of system.

The essential difference is that bifacial solar panels have photovoltaic material (solar cells) on both sides of the module — front and back. If your bifacial PV panel is installed optimally, the rear of the panel won’t receive any direct sunlight. However, a substantial amount of additional electricity can be collected from ambient sunlight alone.
For example, the EcoFlow 220W bifacial portable solar panel boasts a 23% efficiency rating with 220W of rated power on the front and 155W on the rear.

Depending on the surface on which you mount the panel, you could produce up to nearly 25% more electricity.

Bifacial vs. Monofacial Solar Panel Design

The core difference between the two types is their design. Monofacial solar panels have an opaque rear side. In contrast, bifacial solar panels are built with cells on the back and a transparent and highly reflective surface. This means that the monocrystalline cells are exposed to sunlight at the front and back of the panel. Thanks to innovative design, these double-sided solar panels are more efficient at capturing sunlight and converting it to useable energy.

Another benefit of EcoFlow 220W bifacial solar panel is that it doesn’t use metal gridlines and is frameless. It’s stronger structurally than comparable solar panels and is more lightweight and foldable.

Bifacial Solar Panel Price

When it comes to price, it entirely depends on your needs. For comparison, let’s take the EcoFlow 160W monofacial solar panel vs. EcoFlow 220W bifacial solar panel. There’s a +/- $200 price difference between them. While the bifacial solar panel is more expensive, it gives more bang for its buck, achieving up to 25% more energy conversion. This is great for instances where space is valuable to you.

However, it entirely depends on your energy needs. It may be the case that the 220W bifacial solar panel is a little too much for your energy needs. A key takeaway is to assess your energy requirements before deciding between a monofacial or bifacial solar panel. You can find a definitive list of things to consider before buying a solar panel here.

Bifacial Solar Panel: The Difference in Energy Generation 

So why do bifacial solar panels perform better than monofacial solar panels? The answer is the panels on the back, combined with capturing reflected light. For this reason, bifacial solar panels work best when placed next to reflective surfaces. Placing your bifacial solar panel next to a swimming pool or a glass surface on a sunny day is great for energy intake.

Even in snowy conditions, EcoFlow 220W bifacial solar panel can still increase energy production by up to 15% due to reflection. However, the precise amount of energy generated is dependent on conditions surrounding any type of solar panel.

Bifacial Solar Panel Applications

From weekend camping trips to massive floating power stations, bifacial solar panels have a vast array of applications. It’s hard to imagine a circumstance where you wouldn’t want to capture more available sunlight to convert into electricity.  

However, adding additional solar cells to the rear of a panel increases the overall cost. Depending on the surface the panels are mounted on, among other factors, the cost/benefit may not be worth it.

Here are some examples of small and large-scale applications where bifacial solar panels shine compared to monofacial modules. 

Commercial and Utility-Scale Applications

Bifacial solar panels are now standard in utility-scale PV power plants and other commercial applications.

The market share of bifacial solar cells exceeded “60% in 2022 and is expected to exceed 80% in 2032.”

Bifacial solar panels are ideal for purpose-built solar farms and similar installations. Designers can select materials and a layout that maximizes the benefits of bifacial solar panels, such as mounting them on mirrors or another highly reflective surface. 

Other commercial applications for bifacial solar panels include Building integrated PV and Floating PV systems. 

Residential Installations

Unless you’re building a new home, altering the structure of your roof to maximize the benefits of bifacial solar panels is unlikely to be viable.

Carefully weigh up the cost and benefits of installing high-efficiency monofacial rigid solar panels vs. bifacial modules. Depending on your location, climate, roof design and construction, and other factors, the costs of bifacial panels may outweigh the costs.  

Remember to take a long-term view. Generating more electricity means reducing (or eliminating) electricity bills. Bifacial solar panels could shorten your solar payback period and provide a better return on investment over time.  
Portable bifacial solar panels are a no-brainer. Unlike a fixed solar array, it’s easy to change the panel’s position during the day to optimize sunlight capture. If you have any off-grid adventures in your future, the EcoFlow RIVER 2 Pro and 220W bifacial portable solar panel is the perfect way to take electricity to go.

The Benefits of Using an EcoFlow Bifacial Solar Panel

• Increased Energy Conversion Due to bifacial solar panels being able to soak in sunlight from both sides, there is a higher degree of energy generation. EcoFlow’s 220W bifacial solar panel can capture up to 25% more solar energy than traditional solar panels. 

• Durability Designed with thin, one-piece tempered glass, the EcoFlow 220W bifacial solar panel is five times tougher than panels in the same class. Similarly, hot or cold conditions aren’t a problem either. It can withstand temperatures up to 300°F and as low as -4°F. 

• Portability We deliberately made our 220W bifacial solar panel 10% smaller than comparable panels. Why? We wanted the panels to be compact, so you can easily store this in your home or take it on the road to access energy easily and hassle-free. 

• Weatherproof It’s truly built to withstand the elements. It has an IP68 waterproof rating. This means it’s completely dust and water-tight. You’ll be able to generate energy even in the harshest conditions. 

• Innovative Carry Case This case is more than just a protective transport tool. It doubles as an adjustable kickstand. This means you can position your bifacial solar panel to ensure optimal sunlight exposure.  

Disadvantages of Bifacial Solar Panels

Bifacial solar panels enable you to maximize available sunlight with a smaller footprint, but there are a few drawbacks to consider.

Here are the primary disadvantages of bifacial portable solar panels over traditional monofacial PV panels.

Price

Using additional photovoltaic materials, such as monocrystalline silicon solar cells, and adding complexity to the manufacturing process can make the initial investment in bifacial solar panels steeper than monofacial panels.

But not necessarily. EcoFlow’s 220W Bifacial Portable Solar Panel currently costs about 10% less per watt of rated power electricity production than comparable monofacial portable solar panels on the market.

Even if the sticker price is slightly higher per watt of rated power, bifacial solar panels generate more electricity per M₂ of surface area. They are particularly effective on days with fewer hours of peak sunlight. Over the long term, this should lead to a better return on investment and help you achieve solar payback more quickly.  

Less Suitable for Fixed Rooftop Installation

The benefits of portable bifacial solar panels are clear. And they also offer substantially greater electricity generation capacity for industrial or commercial applications where they can be installed a substantial distance above the ground — or even water — especially if the surface is reflective, such as white sand.

The challenge for most residential installations is two-fold. 

Many municipalities, Homeowners Associations, and other authorities restrict the height you can mount your PV panels as measured by distance from the roof. Without sufficient clearance between the roof and the downward-facing side of the bifacial PV panel, you won’t gain much benefit — very little light will reach the photovoltaic surface.

Additionally, surfaces like black asphalt absorb rather than reflect sunlight, reducing any potential gains in electricity production.

Secondly, because residential bifacial solar panel installations are still a relative rarity, the mounting hardware required and installation cost may be significantly more expensive than traditional monofacial panels. Carefully weigh the pros and cons before electing for a home bifacial solar panel installation.

How To Install Bifacial Solar Panels

Portable bifacial solar panels don’t require installation. You can set them up in under a minute anywhere you go with the included kickstand case.

If you’re considering a rooftop bifacial solar panel installation for your home, you’ve got some decisions to make. 

Here are the fundamental steps you should take:

Step 1: To Frame or Not to Frame?

The solar cells in monofacial rigid solar panels are almost always encased in a metal frame. Only the front needs to be transparent. It’s more affordable to use a durable and less expensive material for the back of the frame.

Bifacial solar panels must be transparent on both sides. Typically, solar cells are sandwiched between two pieces of tempered glass — with or without a frame.

Some people find frameless modules more aesthetically pleasing, but looks come at a price. Frameless bifacial solar modules are significantly more challenging to install. If you love the look of frameless PV modules — and don’t mind paying for professional installation — you can stop reading here. 

If you’d like to install framed bifacial solar panels DIY-style, read on!

Step 2: Plan Your Layout

Many of the factors that go into planning an optimal layout for your solar array apply to both bifacial and monofacial panels, such as:

• Available surface area for installation
• Average peak sunlight hours at your location
• Obstructions that will impact how much direct sunlight your PV panels receive daily
• Distance between each PV panel and the cable run from the last panel in the array to the inverter
• Ambient temperature
• Direction, positioning, angle, and tilt

With bifacial solar panels, you also need to consider:

• Roof construction and materials. Reflective surfaces take much better advantage of the rear side of a bifacial panel than a traditional tar or shingled roof.

Step 3: Test Your Solar Panels and Balance of System

It’s crucial to ensure that all of your bifacial solar panels and balance of system components are working before installation. If there is an issue, it will be much easier to track it down on the ground rather than the roof.

You should also decide whether you want to connect your solar panels in series, parallel, or series-parallel (hybrid).

Step 4: Assemble Your Mounting Hardware or Racking System

All rooftop solar panels require mounting hardware or a racking system to ensure they stay securely fastened to your home during a storm or other extreme weather events. 

The type of mounting hardware you require depends on the bifacial solar panels you choose. Follow the manufacturer’s instructions carefully.

Step 5: Mount Solar Panels on Your Roof

If you’ve opted to mount the bifacial PV panels yourself, the first step is to ensure you have a sturdy ladder and some help. 

Most bifacial solar panels have tempered glass on both sides. The panels will be heavy.

Once you have your panels on the roof, arrange them in the configuration you mapped out in Step 2. 

Double-check again that your wiring plan is correct. The panels should be as unobstructed as possible by buildings, trees, and other obstacles that regularly blot out sunlight.

You should aim to leave at least 15 – 20 cm of space between each module to allow easy access for maintenance. 

Additionally, you’re advised not to mount solar panels any closer to 31cm from the edge of your roof. There may even be building code requirements for minimum distance from the roof’s edge in your location. 

Once satisfied that your positioning is optimal, secure the mounting hardware and solar panels.

Step 6: Connect Solar Panels in Series or Parallel

During Step 1, you should have already decided whether you’ll benefit most from connecting your PV panels in series or parallel.

Series Connection

For series connection, connect the positive pole of one module to the negative pole of each module correspondingly. A series connection between identical solar panels quadruples the voltage. Amperage and wattage output remain the same.

For relatively small installations, connecting the panels in series is recommended. 

Parallel Connection 

For parallel connection, please connect the positive and negative cables of one module and the subsequent modules correspondingly. A parallel connection between identical solar panels doubles the amperage. Voltage and wattage output remain the same. 

Step 7: Connect Bifacial Solar Panels to Your Balance of System

Once your bifacial solar panel array is connected in series or parallel, you have one final connection to make. 

Remember to keep the distance between the “last” panel in your array and the inverter (or other BoS component) as short as possible. The longer the cable, the more electricity will be lost in transmission. 

The shorter the connection, the more efficient it will be.

Now, plug the array into your balance of system. 

Congratulations, you’re good to go. 

Step 8: Test Your Residential Solar Power System for 3 Days to 1 Week

Depending on your use case, connecting your solar panels and balance of system to your home circuitry is not essential. 

But if seamless home backup is your goal, you’ll want to take the next step.

Before you do, testing your system before integrating it with your home wiring is wise. 

A trial run is easy if you’re using a whole home generator like the EcoFlow DELTA Pro Ultra. If you’re installing a grid-tied system, it may not be feasible. 

Either way, there’s one last step — and it’s not DIY.

Step 9: Connect Solar Panels to Your Home Circuit Board and Wiring

Integrating bifacial solar panels and your balance of system to your home circuit board and wiring is simple — for a licensed electrician.

Every step up until this point has been well within the capabilities of the average handyperson. Working with high-voltage electrical circuits is not.

Under no circumstances should you attempt to connect your solar panels and balance of system to your home electrical system on your own. 

You must use a licensed electrician. If you don’t, you may be breaking the law, and you’re certainly putting your life and the safety of your home at significant risk.   

The good news is it’s a relatively quick job for a professional. First, you’ll need to purchase a transfer switch or electricity control hub like the EcoFlow Smart Home Panel. 

A transfer switch is a device that switches a load between on-grid power and home backup power. The electrician will integrate the transfer switch with your main circuit panel and connect your balance of system.

Contact your utility provider for a bidirectional meter if you’re going on-grid solar.

Are Bifacial Solar Panels Worth It?

For portable applications where peak sunlight (and space) is at a premium, bifacial solar panels can significantly increase your electricity production using less surface area than a monofacial panel. Often at minimal (if any) additional cost per watt of rated power.

Bifacial solar panels are also increasingly used in large-scale “solar farms” and commercial applications where they can be mounted at a sufficient height on a suitable surface to maximize the additional photovoltaic materials.

However, that doesn’t mean bifacial solar panels are always the best choice for every application. For residential rooftop solar arrays, for example, traditional rigid PV panels may be the wiser choice. In many circumstances, increased electricity will be negligible and could be significantly outweighed by additional installation costs, etc.

Conclusion 

When looking into solar panels, it’s clear that bifacial solar panels are the best options in terms of energy conversion. The transparent design and high degree of reflectivity of bifacial solar panels are a game-changer when it comes to increasing energy production. It has meant bifacial solar panels can pick up more light no matter where you place them.

While double-sided solar panels are still relatively new to the industry, the EcoFlow 220W bifacial solar panel is one of the best out there. Although we may be a little biased, it’s one of the first compact, portable, and durable solar panels that doesn’t compromise energy conversion.

With all said, traditional monofacial solar panels shouldn’t be dismissed entirely. Depending on your energy requirements, you might be better suited with a monofacial solar panel with all factors considered. If you want to check out some solar panels, EcoFlow suite of portable solar panels is an excellent place to start. Interested in diving deeper into the portable solar panel topic?

Frequently Asked Questions

Which Is Better, Bifacial vs Monofacial?

There’s no definitive answer to bifacial PV panels being superior to monofacial. For portable (or industrial) applications, bifacial panels can offer increased electricity generation per square meter than monofacial. Utilizing photovoltaic materials on both sides captures more solar energy by surface area. However, rigid monofacial panels may be better suited for residential installations.

What Is the Lifespan of Bifacial Solar Panels?

Bifacial and monofacial solar panels average lengthy lifespans of 25-30 years. Typically constructed of tempered glass protecting solar cells on both sides, bifacial PV panels tend to be more durable. Whether you choose monofacial or bifacial PV panels for your solar energy needs, purchasing high-quality panels is an investment that will pay off for decades.