Solar Panels: What Is PV Module Degradation and how does It affect efficiency?

Solar panels are celebrated as a clean, sustainable energy solution, but they aren’t immune to the effects of time and nature. Over the years, their efficiency gradually declines, a phenomenon known as degradation.

This decline is caused by factors such as environmental exposure, material aging, and even small manufacturing imperfections. But don’t worry, armed with knowledge and proper care you can ensure your panels remain productive for decades.

What is Solar Panel Efficiency?

Efficiency refers to a solar panel’s ability to convert sunlight into usable electricity. A panel with a 20% efficiency rating converts 20% of the sunlight it absorbs into electrical energy.

Several factors influence this efficiency:

• Material Quality: Panels built with high-grade materials perform better over time.

• Technology: Advanced cell designs like PERC, TOPCon, and HJT ensure higher efficiency.

• Environmental Conditions: Climate, weather significantly impact performance.

  
  

What is Solar Panel Degradation?

Solar panel degradation is an inevitable process that results in a gradual decrease in the panel’s power output over time. This degradation is attributed to various factors, including prolonged exposure to the elements, the natural aging of the materials, and inherent defects in the panel. 

Over time, these factors can cause the photovoltaic cells within the panel to become less effective at converting sunlight into electricity, leading to a decrease in the panel’s overall efficiency.

Average annual degradation rate of pv module

Conditions	Degradation Rate
Average Rate	~0.5% - 0.8% per year	Standard degradation	Varies
Hot Arid Climate	~1.2% per year	Higher degradation	> 35°C
Hot Humid Climates	~1.06% per year	Higher degradation	> 27°C
Cold Arid Climates	~0.72% per year	Very low degradation	< 0°C to 20°C
Temperate Climates	~0.15% per year	Very low degradation	10°C to 20°C

Degradation Rates by solar cell technology

Solar Cell Technology	Annual Degradation Rate
PERT	0.5% - 0.8%
PERL	0.5% - 0.8%
PERC	0.5% - 0.8%
IBC	0.5% - 0.7%
HJT/HIT	0.3% - 0.5%
TOPCon	0.4% - 0.6%

When comparing degradation rates among different solar cell technologies, it's clear that older technologies like PERT, PERL, and PERC generally exhibit higher degradation rates.

In contrast, newer and emerging technologies such as HJT/HIT and TOPCon demonstrate notably lower degradation rates, between 0.3% to 0.5% and 0.4% to 0.6% per year.

These advancements highlight the industry's ongoing efforts to enhance the durability and efficiency of solar cells, ensuring better performance and greater energy output over extended periods​.

Factors Behind Degradation

External Factors

• Thermal Cycling: Daily heating and cooling create micro-cracks in solar cells.

• Moisture Intrusion: Corrosion from humidity damages internal circuits.

• Weather Events: Hail, wind, and rain can physically harm panel surfaces.

  
  

Internal Factors

• Material Aging: Encapsulants and backsheets degrade, exposing sensitive components.

• Design and Installation Flaws: Improper setups can accelerate potential-induced degradation (PID).

  
  

Age-Related Degradation

• As panels age, their protective components weaken, leaving photovoltaic cells vulnerable to environmental stress. This is a slow, natural process, but regular maintenance can help mitigate its impact.

  
  

Potential-Induced Degradation (PID)

• Electrical imbalances across PV modules can cause PID, reducing energy output. Proper inverter selection and installation minimize this issue.

  
  

Light-Induced Degradation (LID)

• LID occurs when panels lose a small amount of efficiency after their first exposure to sunlight. This stabilizes quickly and doesn’t worsen over time, but it highlights the importance of manufacturing quality.

  
  

Back-Sheet Failure

• The backsheet is a crucial protective layer. When it deteriorates, panels are exposed to UV damage, moisture, and electrical hazards. Investing in high-quality backsheets ensures long-term reliability.

How to Maximize Solar Panel Lifespan

While degradation is inevitable, you can take proactive steps to keep your panels running efficiently:

1. Regular Cleaning: Dust, dirt, and debris can block sunlight. Clean your panels regularly to maintain maximum efficiency.

2. Routine Inspections: Check for physical damage, corrosion, or electrical issues.

3. Choose Quality Panels: Opt for panels from reputable manufacturers that adhere to strict quality standards.

4. Optimize Installation: Proper mounting and inverter selection can prevent issues like PID.

5. Monitor Performance: Use solar monitoring systems to detect problems early.

The Importance of Choosing the Right Brand for Longevity

When investing in solar panels, the brand you choose matters more than you might think. High-quality solar panels from reputable manufacturers are designed to withstand environmental stress, maintain efficiency, and last longer. Choosing the right brand ensures not only reliable performance but also peace of mind. 

Make the Right Choice

Investing in a reliable brand is investing in your energy future. Don’t compromise on quality; your solar panels are a long-term asset, and choosing the best ensures you reap the full benefits for decades.

Looking for premium solar panels backed by trusted brands? Visit our web store to explore a wide range of high-quality panels and accessories tailored to your needs.

Have questions or need personalized recommendations? Contact us today our experts are here to help you select the perfect solar solution for your home or business.