Solar panel degradation refers to the gradual loss of efficiency and power output of solar panels over time, primarily due to environmental factors, wear, and tear. Typically, panels degrade at a rate of about 0.5% to 1% per year, meaning they produce less electricity as they age.
As the years pass, the rate of decline stabilizes, resulting in a gradual but consistent decrease in efficiency. By the twentieth year, solar panels typically retain around 80% to 85% of their original efficiency, showcasing the enduring reliability of solar energy systems despite the natural degradation over time.
What is Solar Panel Efficiency?
Solar panel efficiency refers to the ability of a solar panel to convert sunlight into usable electricity. It is a critical factor in determining the overall performance and cost-effectiveness of a solar energy system. The efficiency of a solar panel is typically expressed as a percentage , representing the ratio of sunlight converted into electricity relative to the total sunlight hitting the panel. By 2024, the average efficiency of solar panels will be 21.4%.
Solar Panel Efficiency Over Time
Over the past decade, solar panel efficiency has improved significantly. In 1883, the first rooftop solar panel in New York City had an energy conversion rate of just 1%. By 2010, this efficiency had increased to 15%. Today, most monocrystalline solar panels have an efficiency rating between 19% and 22%.
In 2014, the solar company First Solar set a world record with 20.4% efficiency. Now, thanks to advancements in technology, what was a record ten years ago has become the industry standard. For more information on how to measure solar efficiency, you can check out our article: How is Solar Panel Efficiency Measured?
Solar Panel Degradation Curves
Solar panel degradation typically follows a nonlinear curve, with initial degradation occurring rapidly in the early stages of operation, followed by a more gradual decline over time.
| Year | Efficiency Degradation (%) | Remaining Efficiency (%) |
|---|---|---|
| 1 | 2.5 | 97.5 |
| 2 | 2.3 | 95.2 |
| 3 | 2.0 | 93.2 |
| 4 | 1.8 | 91.4 |
| 5 | 1.5 | 89.9 |
| 6 | 1.3 | 88.6 |
| 7 | 1.2 | 87.4 |
| 8 | 1.0 | 86.4 |
| 9 | 0.8 | 85.6 |
| 10 | 0.7 | 84.9 |
| 11 | 0.6 | 84.3 |
| 12 | 0.5 | 83.8 |
| 13 | 0.4 | 83.4 |
| 14 | 0.3 | 83.1 |
| 15 | 0.2 | 82.9 |
| 16 | 0.2 | 82.7 |
| 17 | 0.1 | 82.6 |
| 18 | 0.1 | 82.5 |
| 19 | 0.1 | 82.4 |
| 20 | 0.1 | 82.3 |
The table above presents a comprehensive overview of the degradation of solar panel efficiency over a twenty-year period. Each row corresponds to a specific year of operation, with accompanying data on the percentage of efficiency degradation and the remaining efficiency percentage.
Efficiency Degradation Percentage: The "Efficiency Degradation (%)" column indicates the annual decrease in efficiency relative to the initial efficiency of the solar panel. These values are based on empirical data and industry research, providing insights into the typical rate of efficiency decline experienced by solar panels over time.
Remaining Efficiency Percentage: The "Remaining Efficiency (%)" column calculates the cumulative impact of efficiency degradation on the overall performance of the solar panel. It represents the percentage of efficiency retained after each year of operation, taking into account the cumulative effect of degradation.
Interpretation:
- In the first year of operation, the solar panel experiences a 2.5% degradation in efficiency, resulting in a remaining efficiency of 97.5%.
- As the years progress, the rate of efficiency degradation gradually decreases, leading to smaller annual reductions in efficiency.
- Despite the diminishing rate of degradation, the cumulative effect over time is significant, with the remaining efficiency gradually decreasing from the initial value.
- By the twentieth year of operation, the solar panel retains approximately 82.3% of its original efficiency, indicating a cumulative degradation of 17.7% over the two-decade period.
Why Does Solar Panel Efficiency Decline Over Time?
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Temperature
- High Temperatures: Elevated temperatures can lead to increased resistance within the solar cells, reducing efficiency. Panels often perform best at cooler temperatures.
- Thermal Cycling: Repeated heating and cooling cycles can cause expansion and contraction, leading to microcracks and structural weaknesses.
-
Humidity
- High humidity levels can promote moisture penetration, which cause corrosion in electrical components and affect the integrity of the panel materials.
-
Light-Induced Degradation (LID)
- LID occurs when solar panels are first exposed to sunlight, leading to a temporary drop in efficiency. This is often due to the recombination of charge carriers in the silicon, which can be more pronounced in certain types of cells.
-
Potential-Induced Degradation (PID)
- PID is a phenomenon where voltage differences between the solar cells and the frame can lead to leakage currents, degrading the performance of the panels. This is particularly relevant in systems with improper grounding or high voltages.
FAQ
What is the efficiency of solar panels after 10 years?
The efficiency of solar panels after a decade of operation varies based on environmental conditions, maintenance practices, and panel quality. On average, solar panels may experience a degradation in efficiency ranging from 10% to 20% over this period.
What is the average efficiency of solar panels over time?
Over time, solar panels typically experience a gradual decline in efficiency due to material degradation and environmental exposure. While designed for long-term performance, panels may undergo an annual efficiency degradation of around 0.5% to 1%, resulting in a cumulative loss over their lifespan.
How efficient are solar panels after 20 years?
After two decades, solar panels usually retain approximately 80% to 85% of their original efficiency. It's crucial to note that this estimate is subject to variation depending on specific system conditions.
