Home Trade association High temperatures are good for solar panels, right? The answer is: it’s complicated

High temperatures are good for solar panels, right? The answer is: it’s complicated


This image, from May 2022, shows solar panels in Worcestershire, England. The recent hot weather in the UK has led to a discussion about the optimum conditions for solar power.

Mike Kemp | In pictures | Getty Images

Last week, temperatures in the UK rose, with highs of over 40 degrees Celsius (104 degrees Fahrenheit) recorded for the first time.

The news from the UK – which has seen a number of significant weather-related disruptions – came as other parts of Europe grappled with a heatwave that brought fires, delays in travel and deaths.

On July 20, Solar Energy UK, citing data from Sheffield Solar’s PV Live site, said the country’s solar power generation had “met up to a quarter of UK electricity demand”. The trade association added that, over 24 hours, solar power had “provided around 66.9 gigawatt hours, or 8.6% of the UK’s electricity needs”.

Many would think that the scorching heat of the past few days would represent the sweet spot for solar PV systems, that convert sunlight directly into electricity.

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The reality is a bit more complex. According to Solar Energy UK, the UK’s solar capacity peaks at temperatures around 25°C.

“For every degree either side of that, it’s lowered by only about 0.5%, although the newer modules have improved performance,” he says.

In a statement, Alastair Buckley, who is a professor of organic electronics at the University of Sheffield and runs Sheffield Solar, said this was “the reason why we never see peak production in mid-summer – the peak of national production is always in April and May when it is cool and sunny”. .” Sheffield Solar is part of the university’s Grantham Center for Sustainable Futures.

Buckley’s argument is supported by the current record for solar production in the UK. It stands at 9.89 GW and was reached on April 22, 2021, according to data from Sheffield Solar.

Temperatures last week were well above 25C, but the overall effect didn’t seem to be too disruptive. Significant acceleration would be needed for major problems to arise, according to Solar Energy UK.

He says panel temperatures are determined by a series of factors: what he calls “radiative heating from the sun,” ambient temperature, and the cooling effects of wind. “Losing 20% ​​efficiency, considered a significant amount, would force them to reach a whopping 65°C.”

So there is clearly a respite for solar panels, but the prospect of warmer summer temperatures on a more regular basis doesn’t seem to bother Chris Hewett, the chief executive of Solar Energy UK.

“It’s slightly better for efficiency in the spring, but essentially if you have more light, you produce more solar energy,” he said last week.

“You have to remember that solar panels work all over the world. The same technology that we put on our roofs is used in the solar farms in the Saudi Arabian desert.”

Solar energy is not the only one to be affected by the rise in temperatures that Europe has experienced.

Last week, it was reported that a nuclear power plant in Switzerland was cutting output to prevent the river that cools it from reaching temperatures dangerous to marine life.

On July 18, the international unit of the Swiss Broadcasting Corporation, quoting the country’s public broadcaster SRF, said that the Beznau nuclear power plant had “temporarily reduced its operations” to prevent the temperature of the Aare from rising “to dangerous levels for fish. “

More broadly, a number of companies involved in renewable energy have highlighted how weather conditions can affect their production. Lower wind speeds, for example, can adversely affect operations.