Understanding Solar Panel Issues and Degradation

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Solar panels are highly reliable and need very little upkeep. Usually, the only maintenance required is occasional cleaning, as they have no moving parts. However, like any product, they can sometimes fail or underperform due to defects in materials or manufacturing, though this is rare. Lower-cost panels are more likely to have issues due to cost-cutting, while higher-quality brands generally have fewer problems. Over time, it’s normal for solar panels to lose a small amount of efficiency as they age. They are built to withstand tough weather conditions like heat, humidity, storms, and even salty air near the coast. Most panels come with warranties – typically a 10-year warranty for defects and a 25-year warranty for performance.

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Common Solar Panel Problems and Gradual Decline

Over a 25-year lifespan, it’s normal for solar panels to lose a bit of efficiency each year. Occasionally, panels might face other issues caused by damage or manufacturing defects. Rarely, severe weather events like hail can crack the glass. Here are six common problems:

Light-Induced Degradation (LID): A small, gradual drop in efficiency (0.25%-0.7% per year) due to exposure to sunlight.
Potential Induced Degradation (PID): Caused by voltage leakage, leading to reduced performance over time.
General Degradation: Problems like moisture or poor manufacturing can cause early failures.
Light and Elevated Temperature Induced Degradation (LeTID): Sudden drops in performance (up to 6%) caused by heat and sunlight.
Micro-Cracks and Hot Spots: Small cracks in the panels can disrupt energy flow and create overheating.
Failed Bypass Diodes: Issues caused by shading, which can lead to overheating and damage.

Gradual Efficiency Loss in Solar Panels

When solar panels are first used, they may lose 2%-3% of their efficiency within the first few hundred hours of sunlight exposure. This is a normal process called “power stabilization.” After the first year, the efficiency loss slows to about 0.3%-0.6% per year. Some high-quality panels degrade even less, around 0.25% per year.

Manufacturers often account for this initial drop by slightly overrating the panel’s capacity. For example, a panel labeled 350W might briefly produce up to 368W during testing.

Specific Issues with Solar Panels

Potential Induced Degradation (PID)

Often occurs 5-10 years after installation due to voltage, heat, or humidity. This problem is more common in large solar farms with high-voltage systems but less likely in residential setups. PID can be reduced with better materials and advanced inverters.

General Degradation

Substandard materials or poor quality control can cause the protective layers on panels to break down, leading to moisture damage or corrosion.

Light and Elevated Temperature Induced Degradation (LeTID)

This issue affects certain types of panels, causing larger drops in performance than LID.

Micro-Cracks and Hot Spots

Tiny cracks can form from mishandling or extreme weather. These cracks can cause hot spots that overheat and damage the panel.

Failed Bypass Diodes

Shading on the panels can overwork bypass diodes, leading to failure. Heavy shading increases this risk, and repairing these diodes may require specialized testing.