It may seem counter-intuitive, but solar panel efficiency is affected negatively by temperature increases. Photovoltaics, or solar panels that produce electricity, are affected by their operating temperature, which is primarily a product of the ambient air temperature as well as the level of sunlight. While the length and strength of sunlight received are more important factors in a solar panel’s power production efficiency, temperature, and other environmental factors can reduce efficiency and lower the solar panel’s energy output.
Thus, while evaluating a solar power plant (for investment or purchase), you should also evaluate how well the solar power plant has been conceptualized, designed and implemented to perform well under high temperatures.
How can you quantify the dependence of solar panels on temperature?
Photovoltaic modules are tested at a temperature of 25 °C (STC) and depending on their installed location, heat can reduce output efficiency by 10-25%. The best way to determine your panel’s tolerance to heat is by going through the manufacturer’s data sheet. There, you’ll see a term called the “temperature coefficient (Pmax)”.This is the maximum power temperature coefficient.
It tells you by how much the power output from the panel is lost when the temperature rises by 1°C above 25°C at STC (STC is the Standard Test Condition at which the module’s rated power is determined).
Now how do you ensure the power output is not compromised under high temperatures?
Make sure the panels (especially when located in high-temperature conditions) can boast of low-temperature coefficients. Temperature coefficients for panels should be as small a value as possible to minimize output losses with increases in temperature beyond 25°C.
Will high temperatures only affect solar panels?
Unfortunately, no. Temperature can adversely impact the output from inverters and also can damage cables which are not adequately rated to withstand prolonged exposure to heat.
When it comes to inverters, they are made to de-rate their power output or in other conditions, made to shut down when they reach certain outside temperatures, say about 55°C.Hence it is critical that you evaluate the ambient operating temperature range for which the inverters can work efficiently.
In the case of cables also, the same applies. Solar cables, when designed and installed carefully, usually will be able to withstand high-temperature conditions. However, you might want to additionally make sure that cables are rated for temperatures up to 120°C.
You might want to check out these questions on Solar Power Plant Evaluation – Location Specifics
- Evaluation of performance during high winds – Here
- Evaluation of performance when exposed to high amounts of dust – Here
- Is the solar power plant located in areas prone to floods and water logging? – Here