The Reality of Solar Panel Degradation in Singapore
Every solar panel degrades. This is not a flaw — it is physics. The question is not whether your panels will lose output over time, but how much, how fast, and what you can do about it. In Singapore's tropical climate, understanding degradation is especially important because the environmental conditions that make solar viable year-round also accelerate certain degradation mechanisms.
This guide covers the science behind panel degradation, what the numbers actually mean for your system's long-term performance, how Singapore's climate specifically affects panel longevity, and how to choose equipment and monitoring strategies that minimise loss.
What Is Solar Panel Degradation?
Solar panel degradation is the gradual, permanent reduction in a panel's power output over time. It results from physical and chemical changes in the panel's materials caused by prolonged exposure to sunlight, heat, humidity, and mechanical stress.
Degradation is measured as the percentage of original rated power lost per year. A panel rated at 540W with 0.5% annual degradation will produce approximately 527W after year 5 and approximately 473W after year 25.
Types of Degradation
Light-Induced Degradation (LID)
LID occurs during the first hours to days of sunlight exposure. When boron-doped silicon (used in P-type cells) is exposed to light, boron-oxygen complexes form that reduce cell efficiency. This initial drop is typically 1–3% for P-type PERC panels.
N-type advantage: N-type cells (TOPCon, HJT, All Back Contact) use phosphorus-doped silicon instead of boron, which eliminates or significantly reduces LID. Premium N-type panels like AIKO's ABC technology experience first-year degradation below 1%. This is one of the most compelling technical reasons to choose N-type technology, especially in Singapore's high-irradiance environment.
Light and Elevated Temperature Induced Degradation (LeTID)
LeTID is a slower degradation mechanism that occurs over months to years when panels are simultaneously exposed to light and high temperatures. It is particularly relevant in tropical climates like Singapore where panel surface temperatures regularly exceed 60°C. LeTID can cause an additional 1–2% loss in P-type panels during the first 1–3 years. N-type panels show significantly lower susceptibility to LeTID.
Potential-Induced Degradation (PID)
PID occurs when high voltage differences between the solar cells and the grounded frame cause ion migration, reducing cell performance. It is accelerated by high humidity and high temperatures — both of which are constant in Singapore. PID can be severe, causing 10–30% output loss if unaddressed, but modern anti-PID panel designs and proper inverter grounding largely prevent it in quality installations.
Encapsulant Yellowing and Delamination
The transparent encapsulant material (typically EVA) that protects the solar cells gradually yellows under UV exposure, reducing light transmission. In tropical environments with intense year-round UV radiation, this process occurs faster than in temperate climates. Delamination — where the encapsulant separates from the glass or cells — allows moisture ingress that accelerates corrosion. Research on photovoltaic modules operating in tropical conditions has identified encapsulant yellowing as one of the most significant long-term degradation drivers.
Cell Micro-Cracking
Thermal cycling (repeated heating during the day and cooling at night), mechanical stress from wind, and even the installation process itself can cause microscopic cracks in solar cells. These cracks may not immediately affect performance but can worsen over time, creating inactive cell regions that reduce output. In Singapore, daily thermal cycling is less extreme than in desert or continental climates, but the constant high temperature baseline means panels spend more cumulative hours under thermal stress.
Degradation Rates: What the Numbers Actually Mean
Industry Benchmarks
Panel TechnologyTypical Annual DegradationOutput at Year 25P-type PERC (budget)0.6–0.8%80–85%P-type PERC (premium)0.45–0.55%86–89%N-type TOPCon0.35–0.45%89–91%N-type HJT0.3–0.4%90–92%N-type ABC (All Back Contact)0.25–0.4%90–94%
Compounding Effect
Degradation compounds. A panel losing 0.5% per year does not lose 12.5% over 25 years (0.5 x 25). It loses slightly less because each year's percentage loss is calculated on the already-reduced output. The actual loss is closer to 11.8%. For practical purposes, the linear approximation is close enough, but precise financial modelling should use compound calculations.
The Lifetime Energy Difference
Over a 25-year system life, the cumulative energy difference between a panel with 0.4% annual degradation and one with 0.7% annual degradation is substantial. For a 10 kWp system producing 13,000 kWh in year 1:
This difference alone often justifies the price premium of better panels.
Singapore's Tropical Climate: Friend and Foe
Advantages
Challenges
How to Minimise Degradation
Choose the Right Panels
Ensure Quality Installation
Monitor Performance Over Time
Degradation and Your Financial Model
When evaluating solar proposals, always ask for a degradation-adjusted production forecast — not just year 1 output. A responsible proposal should show:
If the proposal shows only year 1 production and calculates payback based on that figure held constant for 25 years, the payback period is overstated. Real payback, accounting for degradation, is typically 6–12 months longer than the year-1-based calculation suggests.
Frequently Asked Questions
Can degradation be reversed?
LID can sometimes be partially reversed through thermal annealing (heating the panels to specific temperatures), but this is not practical for installed residential systems. Most forms of degradation are permanent. The focus should be on choosing panels and installation practices that minimise degradation in the first place.
Does cleaning panels reduce degradation?
Cleaning reduces soiling losses but does not reverse degradation. Soiling (dust, pollen, bird droppings) and degradation are separate phenomena. A dirty panel produces less energy, but cleaning it restores it to its current degraded capacity, not its original capacity.
Will my panels stop working after 25 years?
No. The 25-year warranty is a performance guarantee floor, not an expiry date. Most quality panels continue producing electricity well beyond 25 years, albeit at reduced output (typically 80–90% of original capacity). Many installations worldwide have operated for 30–40 years.
Is degradation covered by warranty?
Yes, but only if it exceeds the warranted degradation rate. If your performance warranty guarantees 84% output at year 25 and your panels are producing 85%, there is no warranty claim — even though degradation has occurred. A valid claim requires proving that output has fallen below the warranted level, which requires independent testing. See our contract and warranty guide for details on the claims process.
Understanding degradation does not make solar a bad investment — it makes you a smarter buyer. Even with degradation, solar panels in Singapore pay for themselves in 4–7 years and then deliver 18–21 years of essentially free electricity. The key is choosing equipment and installation practices that keep degradation at the lower end of the spectrum. Read the full 15 Solar Myths guide to understand how degradation fits into the bigger picture.
