The Impact of Heatwaves on Solar Panels

The recent heatwaves across Europe have seen several countries generating record amounts of solar energy. You wouldn’t be alone if you assumed heatwaves were good for solar energy, considering latest records of solar energy production you wouldn’t be wrong. However, intense heat can be very bad for solar panels.


How does extreme heat affect solar panels?


Heat can reduce the ability of solar panels to produce energy and reduce output efficiency by as much as 25%. Solar panels generally have a temperature range of 15°C to 35°C, depending on the type of solar panel. In production, 25°C is the temperature used for testing and is generally seen as the optimum temperature. However, the temperature of solar panels can rise to around 65°C, which impacts their efficiency massively. These temperatures refer to the temperature of the panel itself, not the air.


Solar cells absorb sunlight and convert it into energy which we consume, but not all sunlight absorbed is transformed into power. Some will be turned into heat, which slowly heats up the solar panel thus reducing its efficiency. Solar panels are made up of robust materials, designed to withstand all sorts of weather conditions and there are many factors that will determine the temperature of a solar energy system, not just the air temperature. Dark solar panels are much more likely to reach high temperatures than lighter coloured solar panels.


solar panels


Energy generation from solar panels is maximised in colder, brighter conditions, rather than hotter climates. When sunlight hits a solar cell, the incoming photons create a charge by exciting electrons to a higher energy level. When a solar cell is already at a high temperature, more electrons are already in an excited energy state. This results in the solar panel being able to produce less electricity and therefore a reduction in efficiency.


For every degree rise in temperature, the efficiency of a solar panel is reduced by 0.5%. This can all add up to a considerable amount if the solar panel becomes hot enough.


What can be done to prevent overheating?


  • Using light coloured and reflective material to build a solar panel can help reduce the severity of temperature increases. Darker colours absorb heat much easier and quicker.
  • Another common technique is to mount panels a few inches above the roof in order to allow for air flow underneath which helps with regulating temperature.
  • Installing components like inverters and combiners into shaded areas will help keep them cooler.
  • Selecting a panel with low temperature coefficient if you live in a warmer climate will be a wiser investment.


What do rising temperatures mean for renewable energy?


Energy systems, particularly renewable ones, are highly dependent on the weather and climate which is a bit of a problem when it comes to reliability and stability, particularly if extreme weather events continue to occur more frequently.


Nuclear power plants are impacted by extreme heat and extreme droughts damage hydropower facilities. Wind turbines have previously been damaged by natural disasters and the consequences of climate change also have a strong influence on traditional energy sources.


damaged wind turbine


To help cope with the impact of climate change, the renewable energy industry is having to look at redesigning products and systems in order to be more resilient to adverse weather. Renewable energies are a huge part of climate mitigation and research continues to go into technological innovations to propel and improve these sectors however this needs to be accelerated if we are to achieve a positive, lasting impact on our climate.