The Hidden Power Drain in New Solar Panels: Why a Tiny Silicon Change Makes a Big Difference

Imagine buying a brand-new, high-performance car. The day you drive it off the lot, it feels fantastic. But within just a few hours, it permanently loses nearly 2% of its horsepower. You’d be concerned, right?

This same scenario plays out for countless solar panels the moment they’re installed. It’s a well-known phenomenon called Light-Induced Degradation (LID)—a hidden power drain that has silently affected the solar industry for decades.

But what if this initial power loss could be almost completely eliminated? Recent shifts in solar cell technology promise just that, delivering more stable, reliable power from day one. At PVTestLab, we don’t take claims at face value—we put them to the test. In a recent controlled study, we compared traditional solar cells with their modern counterparts. The results weren’t just interesting; they point to a fundamental improvement in solar technology everyone should understand.

What is Light-Induced Degradation (LID)? A Quick Primer

Light-Induced Degradation is the natural, initial drop in a solar panel’s power output when it’s first exposed to sunlight. This isn’t a long-term wear-and-tear issue; it happens within the first few hours or days of operation and then stabilizes.

For years, the primary culprit behind LID in the most common solar cells (p-type PERC) has been the element Boron.

Boron is used as a „dopant“ to give the silicon wafer the electrical properties it needs. However, when sunlight hits the panel, some Boron atoms team up with stray oxygen atoms naturally present in the silicon. This pairing creates a „Boron-Oxygen complex,“ a tiny defect that traps electrons, preventing them from being converted into electricity. More traps mean less power.

While manufacturers have always accounted for this predictable power loss in their datasheets, it still represents an inherent inefficiency. A 1-2% loss on a multi-megawatt solar farm adds up to a significant amount of lost energy and revenue over the project’s lifetime.

Putting „LID-Free“ Claims to the Test: From Theory to Reality

To combat this problem, many cell manufacturers have switched from Boron to Gallium (Ga) as the primary dopant. In theory, Gallium doesn’t form the same power-sapping complexes with oxygen, making the cells immune to traditional LID.

This sounds great on paper, but how does it perform in a finished module built on a real production line?

To find a definitive answer, we designed a head-to-head comparison. We manufactured two sets of full-scale solar modules in our controlled production environment, carefully isolating just one variable: the cell’s dopant.

• Module A (The Incumbent): Built with 120 M6 half-cut PERC cells using traditional Boron-doping.
• Module B (The Challenger): Built with 120 M6 half-cut PERC cells using modern Gallium-doping.

Everything else—the glass, encapsulant, backsheet, and the critical lamination process—was identical for both module types. This ensured any performance difference would stem directly from the cells themselves, not from a manufacturing variable. It’s a core part of our approach to solar module prototyping: creating a reliable baseline to accurately measure innovation.

Our Methodology: A Real-World Test Under Lab Conditions

To simulate the critical first hours of sunlight exposure, we used a process called „light soaking.“ Both modules were placed inside our climate-controlled light-soaking chamber and exposed to conditions defined by the international standard IEC 61215.

• Irradiance: 1000 W/m² (equivalent to bright, direct noon sunlight)
• Module Temperature: Maintained at 50°C
• Duration: Continued until the modules absorbed an energy dose of 10 kWh/m²

We measured the peak power (Pmax) of each module with our AAA-rated flasher before and after light soaking, using the same real industrial equipment top-tier manufacturers rely on for quality control.

The Results Are In: A Clear Winner Emerges

The data from our test told a clear and compelling story. While both modules started with very similar power outputs, their stability under light exposure was dramatically different.

Boron-Doped Module
Initial Peak Power: 367.6 Wp
Power After Light Soaking: 361.3 Wp
Power Loss (LID): -1.71%

Gallium-Doped Module
Initial Peak Power: 370.0 Wp
Power After Light Soaking: 369.3 Wp
Power Loss (LID): -0.19%

The traditional Boron-doped module lost 1.71% of its initial power—a standard, expected level of LID.

The Gallium-doped module, however, lost a mere 0.19%. This negligible drop confirms that switching to Gallium doping virtually eliminates the Boron-Oxygen degradation mechanism.

The takeaway is unambiguous: The „LID-free“ claims for Gallium-doped PERC cells hold up under controlled, industrial-scale testing. The technology delivers a more stable and reliable module right out of the box.

Why This 1.5% Difference Matters More Than You Think

A difference of 1.52% might not sound like a lot, but its impact on the economics and bankability of a solar project is massive.

1. More Energy, More Revenue: For a 100 MW solar farm, that 1.5% is like having an extra 1.5 MW of generating capacity from day one—for free. Over 25 years, this translates into a substantial amount of additional energy sold to the grid.

2. Improved Financial Modeling: Project developers and investors can model energy yield with greater certainty, reducing risk and potentially securing better financing. The performance you’re promised is the performance you get.

3. Higher Power Ratings: With no significant initial power loss to account for, manufacturers can often sort Ga-doped modules into higher power classes, delivering more value to the customer.

This study validates that a microscopic change at the silicon level delivers a measurable, macroscopic advantage in the field.

Frequently Asked Questions (FAQ)

What is LID again, in simple terms?
LID, or Light-Induced Degradation, is a one-time, permanent drop in a solar panel’s power that occurs within the first few hours or days of sun exposure. It’s caused by defects forming inside the silicon cells.

Why was Boron used for so long if it had this problem?
Boron was the industry standard for decades because of its effectiveness as a dopant and because the underlying patents for p-type silicon cell structures were built around it. The 1-2% LID effect was simply accepted as a standard part of the technology.

Is Gallium-doping a brand new technology?
Not exactly. The benefits of using Gallium have been known for a long time, but the technology was patent-protected. Once those patents expired, manufacturers were free to adopt it on a mass scale, which led to the rapid market shift we see today.

Does this mean all my old Boron-doped panels are bad?
Absolutely not. The LID effect in your panels was accounted for by the manufacturer in their power rating. They’re working exactly as designed. This new technology simply represents an improvement, delivering performance closer to its „fresh out of the factory“ state.

How can I be sure a module is truly low-LID?
While datasheets are a good start, the only reliable way is through independent testing and validation. A controlled light-soaking test, like the one we performed, provides hard data that separates marketing from real-world performance.

The Future is Stable

The shift from Boron to Gallium doping is more than an incremental improvement; it’s a foundational step toward more reliable and efficient solar energy. It closes a long-standing performance gap, ensuring the power a module has when it leaves the factory is the power it delivers for decades to come.

Understanding the materials and processes behind your solar modules is the first step toward optimizing performance and ensuring long-term value. If you are developing new module concepts or evaluating new materials, validating their behavior under real-world conditions is the key to unlocking their full potential.