New Energy Solutions
Bi-Facial Solar Panels: The Rundown
You may have come across the concept of bi-facial solar panels in your solar journey. Many find them confusing, after all they do look very different from the traditional panels we install on our roof. Well, we’re here to answer your questions, what are they? How do they work? And what are they used for? And more to help you become a solar expert!
Key Takeaways:
What Are Bi-Facial Panels?
Bi-facial solar panels capture sunlight from both sides, making them more efficient than traditional mono-facial panels, which only capture sunlight on the front. These panels usually have a dual glass design or a reflective backsheet, and they're designed to reduce energy loss.How Do They Work?
The key advantage of bi-facial panels is their ability to reabsorb sunlight that passes through, thanks to their reflective backs. This can boost energy generation, especially when installed above reflective surfaces like snow or pools.Pros and Cons
Pros: Higher efficiency (up to 30% more energy), increased durability, and reduced degradation.
Cons: Higher upfront and installation costs, plus they're more complex to set up than traditional panels.Best Use and Cost
Bi-facial panels are ideal for large-scale commercial or solar farm installations, where they can be mounted higher for maximum sunlight exposure. They cost more (about $1.80 per watt), but the added energy generation can make them worth it in the right context. They’re not great for residential roofs due to their installation needs.
What Are Bi-Facial Solar Panels?
The majority of bi-facial solar panels are made from monocrystalline solar cells due to their slightly higher efficiency, the main thought behind bi-facial solar panels is maximising efficiency and minimising loss.
Where bi-facial panels can become confusing is in their design, they are usually frameless unlike the panels we are used to seeing. Normal panels, like the ones you would see on the roof of a house have an opaque backsheet, bi-facial solar modules on the other hand, usually have a dual pane of glass or a reflective backsheet.
What are Mono-Facial Solar Panels?
The majority of panels installed in Australia are mono-facial. They have an opaque backsheet allowing them to be installed on top of the roof and often will lay flat or slightly tilted to maximise their efficiency. The backsheet on mono-facial panels means they can only generate power through the front face.
How Do Bi-Facial Solar Panels Work?
Although these panels feature drastic differences in design from their sister mono-facial panels, they work just like normal PV modules! The key difference is lost sunlight has the chance to be reabsorbed by the solar cells.
The problem with an opaque backsheet seen in many of our widely used solar panels is loss of sunlight in the generation process. In a normal solar panel there are three categories, sunlight absorbed by the solar cells and converted into electricity, sunlight that becomes trapped in the glass and bounces around until it is eventually absorbed by the cells and lastly a portion of light that passes right through.
With a bi-facial solar panel the sunlight that passes right through the panel has another chance to be reabsorbed and converted into solar energy. The reflective backsheet or surface behind the panel allows the light to bounce off and travel back through the panel’s cells.
Can Bi-Facial Solar Panels Produce More Energy?
These panels, to be really effective, must be installed with a reflective surface behind them such as a pool or snow. Manufacturers claim an increase in efficiency of 30% although this is hard to substantiate due to the lack of widespread use of this technology.
Pros & Cons of Bi-Facial Solar Panels:
Benefits:
Increased efficiency: the ability to absorb sunlight from both sides of the module lead to an overall increase in energy generation, due to this less space and fewer panels are required to produce the same amount of electricity.
Increased Durability: bi-facial panels are frameless and use tempered glass to increase structural integrity. This makes them weather and UV resistant and can also withstand high temperatures and strong winds. Due to all of this bi-facial panels are supposed to have a longer lifespan.
Aesthetics: bi-facial panels come in a range of designs, many of these frameless which can be appealing to some.
Reduced PID (Potential Induced Degradation): the solar cells comprising bi-facial solar panels are less likely to suffer from PID, Potential Induced Degradation is a result of electrical currents straying from their ordinary path, corroding the panel over time. The lack of framing and other metal components makes this less of an issue for bi-facial panels.
Drawbacks:
Initial Costs: bi-facial solar panels can cost up to 10% more than normal, mono-facial panels. This is largely due to the complexity of the manufacturing process.
Installation Costs: these panels are heavier and require more equipment to install. This equipment is often specialised to meet the specific installation needs of bi-facial panels. All of this together means the cost of installing these panels is higher.
Types of Bi-Facial Solar Panels
There are two main types of bi-facial solar panels on the market:
Dual Glass Bi-Facial Solar Panels:
These panels feature a tempered glass pane on each face, front and back. This makes them the most resilient kind of bi-facial panel, allowing them to withstand heavy snow, strong winds and hail. The downside of this is the added weight, dual glass panels are heavier than other models of bi-facial panels.
Glass Back Sheet Bi-Facial Solar Panels:
These panels feature a tempered glass panel on the front face and a lightweight backsheet on the back face. The benefit of this is they are lighter than their counterpart and as such easier to install.
Main Differences:
Dual glass panels are more weather resistant while glass backsheet panels are usually more affordable.
How Much Do Bi-Facial Solar Panels Cost?
Bi-facial panels are typically more expensive than mono-facial panels due to greater complexity in the manufacturing and installation process. The average cost of a bi-facial panel is around $1.80 per watt. For example a 200W bi-facial solar panel will usually cost around $360.
If you want to compare the cost per watt of different panels to get a better idea of value for money the formula for this is below:
Installation Process for Bi-Facial Solar Panels
STEP 1: Prepare the Installation Site
Ensure that the area is clean and ready for the installation team to fit the system, this could include levelling the ground or painting the area behind the panels either white, silver or another colour which will reflect sunlight.
STEP 2: Install Racks & Other Mounting Equipment
The installation team will then install mounting equipment such as racks or brackets, which components and the complexity of this step is determined by the type of installation and proposed system design.
STEP 3: Install the Solar Panels
Once all of the mounting equipment has been installed the bi-facial solar panels will then be placed and fitted according to the system design.
STEP 4: Connect All Wiring
Your installer will connect all of the necessary wiring, ensuring that these connections are tight and that adequate insulation has been applied to electrical cabling.
STEP 5: Test the System
Your installer will then test that the system functions correctly and safely by running a series of tests.
Where are Bi-Facial Solar Panels the Best Fit?
For bi-facial solar panels to be efficient they must be installed at least 1 metre from the ground, although they are most effective when installed around 4 metres off of the ground. This higher positioning allows them to absorb more light throughout the course of the day.
Where Bi-Facial Panels are NOT IDEAL:
These panels aren’t best suited to residential installations due to their double sided nature making roof installation difficult. This paired with the elevation necessary to see a beneficial increase in energy generation means they aren’t the best option for installation in your home.
Where Bi-Facial Panels are IDEAL:
These panels aren’t best suited to residential installations due to their double sided nature making roof installation difficult. This paired with the elevation necessary to see a beneficial increase in energy generation means they aren’t the best option for installation in your home.
Mono-Facial vs Bi-Facial: Comparison
| Bi-Facial Solar Modules | Mono-Facial Solar Modules | |
|---|---|---|
| Light Capturing | Front & back faces | ONLY front face |
| Efficiency & Performance | Can capture more sunlight, manufacturers claim they are 30% more efficient | Slightly less efficient a capturing sunlight |
| How Easy is Installation | Installation is more challenging as the back of the panel needs to be exposed to sunlight. | Installation is more simple as these panels are laid flat or directly onto mounts. |
| Aesthetics | Greater array of designs available as these panels are frameless | Design options more limited. |
| Cost to Install | Typically more expensive (higher production & installation costs) | More affordable option |
| Tilt or Angle of Panels | Can be installed at different tilts or angles to suit the aesthetic and structural needs of the project | Can also be installed at different tilts or angles, although this depends on sunlight rather than visual appeal. |
| Ideal Use of the Panels | Installed on a reflective or flat roof, the panels must have at least 1 metre clearance. | Quite versatile - suitable for a variety of installations. |
| Ideal Client for Each Panel | Large scale projects such as a solar farm or extensive commercial installation | Those looking for a small scale residential installation with a pitched roof. |
FAQ
Frequently Asked Questions about Installing Solar Power
There are great government rebates/incentives still in place for eligible households. Basically, the larger the panel array, the more STCs your solar system generates as it is based on the expected output of the system over time.
When you buy a solar system, the purchase price is normally reduced by the value of the STCs created by your system. You simply fill out a form on the day of installation to confirm that the system has been installed, and that’s it. There is no additional paperwork that you need to do.
Small-scale Technology Certificates (STCs)
Small-scale Technology Certificates (STC’s) – previously known as Renewable Energy Certificates or RECS – are created when a Renewable Energy System such as a Solar PV system is installed.
The number of STC’s depends on the predicted amount of energy generated and hence the larger the system the greater the rebate. In essence, one STC is created for every megawatt-hour of production capacity of the system.
This is further multiplied by the number of years the system is likely to generate energy (for home solar systems, this is usually 15 years, although the life of the solar panels themselves is considerably more than that).
This incentive program is being phased out until 2030, so each year the number of certificates your system is eligible for reduces.
STC Price
The system for trading and pricing STCs for small systems is managed by the Small-scale Renewable Energy Scheme (SRES).
STCs are bought by Liable Parties (usually electricity retailers) and must be surrendered at the end of each quarter. As the number of STCs that are required to be surrendered is a fixed amount each year, but the number of STCs created is variable, the price paid for STCs also varies and is determined by supply and demand.
The Federal Government legislated in 2010 a fixed price for STCs by implementing a Clearing House system where STCs can be bought and sold for $40. However, there is no requirement for Liable Parties to purchase from the Clearing House, so they are likely to only do so if there is a shortage of STCs or the market price exceeds $40. There is currently a surplus of STCs in the market which means the market price of STC’s below $40
The Feed In Tariff is only something you need to worry about if you don’t have battery storage.
The price your chosen energy retailer pays for any excess electricity generated from your solar panels is recorded as a credit on your power bill.
In NSW, solar power is fed into your home as it is generated and your household will use it first before you draw power from the grid.
This means that for every kWh of solar power used in the home you are directly saving money you’d spend on your power bill. This reduction in your power bill is the main financial benefit of solar power.
Everything else will be bought up at an agreed rate by your electricity retailer.
At the moment, most feed-in tariffs are between 5 and 10 cents per kWh, with many being about 7 cents. They bounce up and down a lot, for example in previous years they have been up over 20 cents per kWh. Typically, they are always at least 5 cents per kWh.
Once you sign up for a 1KOMMA5° Installation, we immediately submit your grid application to the relevant energy distributor. For systems up to 5kWs, this is a formality. For larger systems it can take a few days or more. Once we receive approval, your installation will be managed by our installation coordinator, who will welcome you to 1KOMMA5° and book an installation date for you. This is generally booked within around two weeks and installation dates are available Monday to Friday, weather permitting.
We endeavour to have your system installed within 2-4 weeks unless you request us to hold for whatever reason. Due to our strict safety policy, we do not install solar systems when it rains. In the event of inclement weather, we will rebook your installation as soon as possible. We always work with your requests as we strongly recommend that someone be home on the day of installation.
Green Loans can be an affordable way to pay for your solar power system and is only available for approved products. As a Clean Energy Council Accredited installer, all our systems qualify.
Green Loans can be used to finance 1KOMMA5° systems from $1,000 to $30,000 over a 2-7 year term. Once you have received a referral from 1KOMMA5°, online approval usually occurs within 1-2 business days. Green Loans have a competitive fixed interest rate that is as low as 7.99% p.a.* | Comparison rate 9.21% p.a.^ Establishment fee of $299 added to the loan amount. $2.70 per week account keeping fee included in repayments.
To be eligible to apply you must:
Be over 18 years old and an Australian resident or citizen
Own or be purchasing a home
Be employed, self-employed, a self-funded retiree; or is receiving the Government Age Pension
Have an Australian driver’s license or Passport
Provide two most recent payslips or 90 days of bank statements
There are a number of good, competitive Green Loan providers – ask us about the options available.
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