There are no mainstream solar panel technologies with a positive temperature coefficient. In fact, all common photovoltaic (PV) technologies exhibit a negative temperature coefficient, meaning their power output decreases as temperature rises.
Explanation of Temperature Coefficient in Solar Panels
- The temperature coefficient measures how much a solar panel’s output power degrades per degree Celsius increase in temperature relative to a standard test condition of 25°C (77°F).
- It is typically expressed as a percentage loss in power per °C above this baseline.
- Most solar panels have a negative temperature coefficient. For example, common values are about -0.3%/°C to -0.5%/°C, meaning a 1°C increase above 25°C causes about a 0.3-0.5% efficiency loss.
Technology-specific temperature coefficients
- Monocrystalline and polycrystalline silicon panels typically have coefficients around -0.3% to -0.5%/°C.
- Heterojunction (HJT) technology solar panels, which use a thin amorphous silicon layer on crystalline silicon, have even lower negative coefficients, approximately -0.2% to -0.3%/°C. This means HJT panels degrade less with rising temperature but still show negative correlation.
- Thin-film technologies generally have lower negative temperature coefficients (around -0.2%/°C), which is better performance at high temperatures, but still negative.
No Positive Coefficient Reported
- Negative temperature coefficients are inherent to the semiconductor physics involved in PV cells—the open-circuit voltage and max power point voltage decrease as temperature increases.
- While the power output degrades with temperature, solar panels never gain efficiency by heating up, so a positive temperature coefficient is not seen in standard PV devices.
- Manufacturers and industry literature consistently report negative temperature coefficients across all prevailing solar technologies, including advanced types like HJT.
Summary Table of Typical Temperature Coefficients
| Solar Panel Technology | Typical Temperature Coefficient (%/°C) |
|---|---|
| Monocrystalline Si | -0.3% to -0.5% |
| Polycrystalline Si | -0.4% to -0.5% |
| Heterojunction (HJT) | -0.2% to -0.3% |
| Thin-film (e.g., CdTe) | Around -0.2% |
Conclusion
All established solar panel technologies have negative temperature coefficients, meaning efficiency falls as temperature rises. There are no known solar panel types with a positive temperature coefficient in practical use.
This temperature-dependent behavior is fundamental to photovoltaic physics and consistent across different PV technologies.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/are-there-any-solar-panel-technologies-with-a-positive-temperature-coefficient/
