Glass-to-Transparent Backsheet vs. Glass-to-Glass Solar Modules: A Detailed Comparison

Bifacial solar panels utilize the backside material to capture reflected sunlight, thereby enhancing their energy generation capability. Normally, we compare glass-to-transparent backsheet and glass-to-glass options. While both have performance trade-offs and advantages, there are also factors, such as durability and cost, that need to be considered for specific applications.

This blog will provide a basic and straightforward comparison of the two options for glass-to-backsheet and glass-to-glass solar modules on the market. We will consider performance, durability, cost, and applications so that you can make an informed decision based on your needs.

Acknowledging the Basics

What are Bifacial Solar Modules?

Bifacial solar modules are a type of solar panel that can collect light from both directions simultaneously. The front side, like any other panel, absorbs direct sunlight, while the reverse side collects light that reflects off the ground or other nearby objects. This contributes to increased energy generation. White roofs and light-colored tiles, for example, allow more sunlight to reflect back, making them perfect for use over such surfaces.

Common Rear-side Configurations

Now, here’s where the rear-side material makes all the difference. There are two common types:Glass-to-glass (G2G) and glass-to-transparent backsheet (G2B). G2G has toughened glass on both the front and rear. It’s strong and designed to last. However, it may be heavier and more expensive.

G2B replaces the rear glass with a translucent backsheet, which is lighter and typically cheaper. It still allows light to reach the back cells, ensuring that power gain is not lost. But it may not be as durable as glass.

Both have their strengths; it’s not about which is better, but which fits your needs better. If you’re wondering how to pick the right backsheet for your project, you might want to check out this guide on factors to consider while choosing a solar backsheet.

Glass to Glass (G2G) Solar Modules

What is G2G: Know the Construction: Glass-to-glass (G2G) solar modules have tempered glass on both the front and rear. Solar cells are sandwiched between these two glass layers, providing excellent protection against environmental wear and tear. This setup adds strength, improves safety, and boosts overall durability.

Advantages of G2G Solar Modules

High mechanical strength: Can handle strong winds, heavy snow, and physical stress better than most.
Enhanced long-term durability: Resistant to moisture, UV, and chemical corrosion, leading to longer operational life.
Better fire resistance: All-glass structure makes it more fire-safe.
Lower risk of backsheet degradation: No plastic backsheet means no risk of yellowing or peeling.
Improved resistance in harsh environments: Great for coastal areas, deserts, or snowy regions.

Potential Drawbacks of G2G Solar Modules

Heavier weight: Makes handling, transportation, and rooftop mounting more challenging.
Higher material and shipping costs: Two sheets of glass naturally cost more to produce and move.
Complex installation in some cases: May require stronger mounting systems and structural assessment.
May not suit lightweight rooftops: Not ideal for structures that can’t handle added load.

Glass to Transparent Backsheet (G2B) Solar Modules

What is G2B: Know the Construction: The front side of glass-to-transparent backsheet (G2B) solar modules is tempered glass, as is the case with other types of solar panels. The back, however, is made of a translucent polymer sheet rather than glass. This backsheet enables bifacial solar cells to generate power from both sides, with the front facing the sun and the back catching reflected light from its surroundings.

The structure is lightweight and flexible, making it easier to install, especially on rooftops where load limits exist. While it provides basic protection, understanding the properties of a transparent solar backsheet, such as UV stability, strength, and light transmittance, is crucial for predicting how well the module will perform over time.

Advantages of G2B Solar Modules

Lighter weight: Much easier to lift, move, and install, especially on rooftops.
Faster and simpler handling: Installers have an easier time with these compared to heavier glass panels.
Lower production and shipping costs: Using polymer instead of a second glass layer cuts down on expenses.
More rooftop friendly: Ideal for structures that cannot support too much load.

Potential Drawbacks of G2B Solar Modules

Potentially lower durability: The polymer backsheet is more prone to wear and tear over time.
Susceptibility to UV damage and weathering: Some materials may yellow, crack, or lose transparency, especially under strong sunlight.
Not as fire resistant: Compared to full glass modules, polymer sheets can be less robust under high temperatures.

G2G vs. G2B: A Detailed Comparison

Let’s understand the difference between Glass to Glass (G2G) and Glass to Transparent Backsheet (G2B) solar modules. Both are utilized in bifacial solar systems, however, they do not share the same characteristics. They are constructed differently, behave differently, and perform differently under diverse conditions. This is how they stack up.

Durability and Lifespan

When it comes to how tough a module is, G2G wins hands down. These panels are made with tempered glass on both sides, which means they can handle rough weather, sandstorms, and even small impacts better than most. The double-glass structure also helps resist Potential-Induced Degradation (PID) and protects against microcracks that might form due to stress or long-term exposure.

On the other hand, G2B panels have a transparent polymer film on the back. While this makes the panel lighter, it may be more susceptible to wear and strain. Some polymers may break down faster when exposed to UV light or moisture, affecting performance over time.

Weight and Handling

This is where G2B takes the cake. The polymer backsheet makes it lighter than a G2G panel. This makes it easier to transport, hoist, and install, particularly on rooftops where the structure cannot support too much weight. It’s also easier to manage logistics, from packaging and transporting to mounting, saving time and effort.

G2G, being heavier, needs stronger support structures and a little more muscle during installation. Not a deal-breaker, but something to keep in mind if you’re short on hands or space.

Energy Yield and Bifaciality

Both types support bifacial solar cells, which generate power from both sides. However, rear-side efficiency may vary. G2G panels typically allow better light transmission at the back due to the clarity and consistency of the glass. This implies they often function better in regions with high albedo, or surfaces that reflect more light, such as white concrete.

G2B panels continue to absorb rear-side light, although depending on the characteristics of the backsheet, they may allow in less light than glass. So, if the site has poor reflectivity or the backsheet is not adjusted, the total energy yield may be slightly reduced.

Cost Considerations

G2B modules are typically cheaper to manufacture. The polymer sheet is less expensive than a second layer of glass. This also reduces transportation expenses and makes the whole installation budget more manageable. However, depending on how well the polymer lasts over time, maintenance may be required more frequently.

G2G is more expensive up front since it has heavier glass, a greater shipping weight, and requires better mounting. However, the payback is in long-term performance and durability, therefore the investment is amortized over time.

Environmental Impact and Recycling

Here’s the green angle. Glass is completely recyclable. So, when a G2G module reaches the end of its useful life, it may be disassembled and its materials reused more simply.

G2B, while still recyclable, contains polymer elements that may be more difficult to process and generate more waste if not treated appropriately. The sustainability edge favors glass, particularly for long-term environmental goals.

When to Choose a Glass-to-Glass Solar Module?

If your project is in a tough environment like a desert, a coastal area, or a place that gets heavy snow, then Glass to Glass (G2G) solar modules are the way to go. Why? Because they are built like a tank. With tempered glass on both sides, they can handle dust, moisture, snow loads, and even strong winds much better than other options. They also resist microcracks and PID issues over time. So if you’re setting up a large solar farm or a long-term utility-scale project, G2G panels offer more stability and long-lasting output. It’s a one-time investment that pays off without giving you headaches down the road.

When to Choose Glass as a Backsheet Solar Module?

Now, if your focus is on rooftop setups, commercial spaces, or projects where the structure can’t carry too much weight, go with Glass to Transparent Backsheet (G2B) modules. These are lighter, easier to install, and help reduce logistics and mounting costs. G2B still supports bifacial power gain and gets the job done without putting too much stress on the roof. It’s the classic “don’t carry a sledgehammer to crack a nut” situation- you don’t always need the heaviest tool for the job.

Final Takeaway

So here’s the bottom line: Glass to Glass (G2G) modules offer higher durability, better protection against harsh weather, and are great for long-term, utility-scale projects. On the other hand, Glass to transparent Backsheet (G2B) modules are lighter, less expensive, and easier to install, making them perfect for rooftops and commercial applications with weight restrictions.

Your project’s size, location, and budget will all influence your decision. No need to reinvent the wheel; simply match the module to the site’s requirements. And, as bifacial technology advances quickly, both types will only improve.

At the end of the day, it doesn’t matter which is better. It is all about finding the greatest fit. Play your cards correctly, and you’ll achieve superior performance without overengineering the system.