2025.08.22
High temperatures can significantly reduce the power generation efficiency of solar panels and may accelerate the aging of their materials, shortening their service life. Especially in hot areas in summer, it will directly affect the power generation efficiency and long-term reliability of photovoltaic systems. Below, we explain this in detail from several perspectives:
I. Negative Impact on Power Generation Efficiency (The Most Core Impact)
The core of solar panels is semiconductor material (primarily silicon), which has the characteristic of decreasing efficiency as temperatures rise.
1. Power Temperature Coefficient
This is a key metric that measures how solar panel performance is affected by temperature. It is a negative value, typically stated in solar panel specifications, expressed in %/°C.
For example, a panel's power temperature coefficient is -0.38%/°C. This means that for every 1°C increase in the panel's temperature (not the ambient temperature), its output power decreases by 0.38%.
Practical Calculation: Assume a 400W panel under standard test conditions (STC, cell temperature 25°C). On a hot summer day, its surface temperature may reach 65°C (this is common; ambient temperatures may be only 35-38°C, but panel temperatures can be much higher due to direct sunlight).
Temperature Difference: 65°C - 25°C = 40°C
Power Loss: 40°C × 0.38%/°C = 15.2%
Actual Output Power: 400W × (1 - 15.2%) ≈ 339W
Conclusion: A nominal 400W panel may only produce around 340W at high temperatures, resulting in significant efficiency loss. This is why a solar system may produce less power during strong midday sunlight than during cool, sunny mornings or afternoons.
2. Voltage Drop
High temperatures primarily cause a significant drop in the open-circuit voltage (Voc) and operating voltage (Vmp) of a solar panel. Voltage is one of the key factors in generating power (P=V1). A voltage drop directly leads to a decrease in power output.
II. Potential Impacts on Lifespan and Reliability (Long-Term Impacts)
Long-term exposure to high temperatures accelerates the physical and chemical degradation of various solar panelhttps://www.sun-earth.com/products.html components.
1. Accelerated Material Aging
Encapsulation Materials (EVA/POE): High temperatures accelerate the yellowing and degradation of the encapsulation film, resulting in reduced light transmittance and, in turn, impacting power generation efficiency.
Backsheet: High temperatures can cause the backsheet material to become brittle and crack, impacting insulation and weather resistance.
Junction Box and Solder Ribbons: High temperatures exacerbate thermal expansion and contraction, potentially causing fatigue and breakage of internal solder ribbons, overheating damage to diodes and connectors within the junction box, and even leading to failures (such as the hot spot effect).
2. Hot Spot Effect
When a panel is partially obscured (by leaves, bird droppings, or dust), the obscured cells stop generating power and become a load, consuming the energy generated by other cells and converting it into heat.
High temperatures exacerbate this process, leading to localized overheating (possibly exceeding 100°C), permanently damaging the cell and even causing glass cracking.
3. Potential-Induced Degradation
While the PID effect is primarily associated with high voltage, high temperature and humidity can significantly accelerate this process, causing severe and irreversible degradation of cell performance.
III. How to Mitigate the Impact of High Temperatures?
While we cannot change the weather, we can mitigate the effects of high temperatures through system design and maintenance.
1. Choose Modules with Low Temperature Coefficients
When purchasing solar panels, especially in hot regions, prioritize those with a low power temperature coefficient (e.g., -0.34%/°C versus -0.40%/°C). N-type cells (such as HJT and TOPCon) generally have a lower temperature coefficient than traditional P-type cells.
2. Ensure Good Ventilation and Heat Dissipation
Leave Clearance During Installation: Do not install the panels completely against the roof. Leave ample ventilation space (typically at least 10-15 cm) to allow air to circulate behind the panels and dissipate heat.
Choose light-colored or reflective roofs: Dark roofs absorb heat significantly, heating the air behind the panels. Light-colored or reflective roofs can lower the base ambient temperature.
3. Appropriate system design
Inverter matching: Understanding local high temperature conditions, consider oversizing the system capacity (slightly oversizing the DC side power to the AC side power). Because actual DC side power decreases at high temperatures, this allows the inverter to operate closer to full capacity most of the time, improving system utilization.
4. Regular cleaning and maintenance
Promptly removing obstructions such as dust, bird droppings, and leaves from the panels not only ensures sunlight but also effectively prevents hot spot effects, which is especially important in high-temperature environments.
In short, when assessing a region's solar power generation potential, consider more than just sunshine duration and intensity; ambient temperature is also a crucial factor. Fully considering the impact of high temperatures during system design and equipment selection is key to ensuring the long-term stable and efficient operation of a photovoltaic power station.
Keywords：
Sun Earth Solar, Ningbo Sun Earth, Sun-Earth, Sun Earth, solar panel
