Tropical temperatures in Czechia reduce solar output; technology also matters

Current tropical temperatures are reducing the output of solar power plants, generally by a few percent compared with ideal conditions. Industry representatives say this does not automatically mean summer is worse for solar power, as the lower output is usually offset by stronger sunlight and longer days. They also point out that the technology used matters. This is based on comments from industry associations and manufacturers to the Czech News Agency. Wednesday was the hottest day of the year so far in Czechia. Temperatures reached up to 35 degrees across most of the country.

„Solar panel output is lower at high temperatures because silicon performs better at low temperatures. The difference in output between temperatures of 25 and 35 degrees can be five to ten percent,“ said Jan Krčmář, executive director of the Solar Association.

He noted that in the summer months, however, lower output is offset by stronger sunlight and longer days.

Štěpán Chalupa, head of the Chamber of Renewable Energy Sources (OZE), also acknowledged that solar panel output can be lower by a few percent. „But I don’t consider it a problem. The technology can handle it and can operate in areas with much higher temperatures. Whether it is a manufacturer generating electricity for its own consumption or a trader, they know how panels’ output varies and can therefore forecast generation accurately and manage consumption or other flexibility resources,“ he said.

According to Chalupa, experience has shown that May and June offer the best conditions for generating electricity from photovoltaics. He also noted that generation is affected by several factors, including the installation method and the orientation and tilt of the panels, as well as the weather, the length of the day and, consequently, the temperature.

According to S-Power Energies, cool, sunny weather is best for solar panels in terms of output. „They therefore perform best on sunny winter days, but the sun shines on them for only a short part of the day and often not at an optimal angle. In the hot summer, the output of individual panels is somewhat lower. But the output of the entire power plant is considerably higher than in winter, because the longer hours of sunshine and better angle of the sun’s rays offset the hot weather,“ said the company’s director, Jaroslav Šuvarský.

He noted that a whole range of factors are crucial to the optimal performance of photovoltaic power plants, especially the technology they use and whether they are even partially shaded.

Wednesday was the hottest day of the year so far in Czechia. Temperatures reached up to 35 degrees across most of the country, with the highest reading of 37.1 degrees Celsius recorded in Strážnice in South Moravia.