As a result of the gloomy summer in 2021, solar power production should be below average. But the calculation is not quite that simple, however. Meanwhile, the construction of solar collectors and solar panels continues to boom.
Cloudy, rainy and cool weather, accompanied by strong storms and even hailstorms: this is how the past summer will be remembered. This not only had an influence on the mood of many people, but probably also on the production of solar energy.
Compared to the strong previous year of 2020, there was indeed a difference in electricity production, says Karin Wyss-Iten of the Ägerital Energie Genossenschaft (Aegeri Valley Energy Cooperative). "However, this was not only partly due to last year's strong summer, but also to the snowy winter," she adds. Yields in the first nine months of this year are 20% lower than in the previous year.
"The biggest difference in production occurred in the months of January and April"
she adds. There was much less snow in the previous year, and April 2020 was also extremely sunny. "It should also be mentioned that June 2021 was around 8% better than in the previous year."
The Ägerital Energie Genossenschaft has so far connected 13 photovoltaic systems to the power grid, with around 840,000 kilowatt hours of electricity being produced per year. This corresponds approximately to the needs of 210 households. The facilities can be found in the Ägerital and in Menzingen, for example, on large barn roofs, on the roof of the Municipal Workshop (Werkhof) or on the Luegeten retirement and care centre in Menzingen.
Karin Wyss adds: "It turns out that, although there are differences, these balance out over the years." For the Ägerital Energie Genossenschaft, this means that budgeting is carried out cautiously, and they are always happy about sunny weather. "Experience has shown that bad weather shouldn’t get us into problems," she adds. The cooperative's facilities were spared from damage from the hailstorms in June.
Production down 14% from last year
Stephan Müller, Managing Director of the Elektro-Genossenschaft Hünenberg (EGH: Electricity Cooperative Hünenberg), draws a similar conclusion: "When I look at our own 12 photovoltaic systems, production from January to August 2021 was lower than in the previous year." An exception here was June. On the one hand, Müller bases this on the large amount of snow that lay on the facilities until spring and, on the other, on the fact that the spring and summer months generally had fewer sunny days:
"Production in this period was around 14% lower than in 2020, taking into account that 2020 was one of the best years ever."
In addition to the 12 own plants, a total of 100 photovoltaic systems with a total annual output of around 1.02 gigawatt hours are in operation in the EGH grid area. They were also spared from damage from the hail storms.
Unlike the installation on the roofs of Risi Immobilien AG in Gulmmatt in Baar, which has only been in operation since last March. The 7,500 square metre facility is the most powerful in the canton of Zug to date, and can reach a peak output of 1,500 kilowatt. That would be enough to supply 330 single-family homes. At the end of June, however, 80% of this was destroyed by the storms or hail. "The damage amounts to around CHF one million, without the loss of business that was not insured," says Adrian Risi, Managing Director of Risi Immobilien AG.
Repair work is in full swing at the moment, with half of the plant already back on the grid. The entire installation should be fully operative again by November.
Photovoltaic systems, such as here in the Gulmmatt in Baar, were damaged by hail in many places this summer.
Muhamet Kamberi, fitter at Suter&Partner, installs the new panels on the roof of Risi Immobilien AG in Baar.
Photos: Matthias Jurt (October 8, 2021)
Around a dozen photovoltaic systems were damaged
The cantonal facilities have also suffered, with damage amounting to about CHF 250,000, writes construction director FLorian Weber. The damage was reported to the Building Insurance (Gebäudeversicherung) Zug (GVZG) and is also covered by it. Richard Schärer, Director of the GVZG, speaks of "a few dozen larger and smaller solar and photovoltaic systems" that were damaged by hail in the canton of Zug.
The primary focus is currently on damage management. "An evaluation of the amount of damage to solar systems or other individual components involves a considerable effort, and is therefore currently not of the highest urgency," he explains. It’s currently assumed that the damage to the installations would be in the lower double-digit million range. The municipalities of Cham, Hünenberg, Steinhausen and Baar were particularly affected.
Concrete figures as to whether the poor summer has had an impact on the production of solar energy are not yet available from the canton. This is because the canton's electricity production is evaluated on the basis of annual revenues. "The data for 2021 will not be available until the first quarter of 2022," says Florian Weber.
5% of the electricity demand is covered by solar power
In general, solar power production is booming in the canton of Zug. While only around 1% of the total electricity demand was generated by photovoltaic systems in 2017, this had already increased to 5% by 2020. "We hope that this positive development will continue," says the Construction Director. This is certainly possible. Theoretically, up to a third of the canton's electricity demand could be generated by solar energy.
The considerable increase in the production of solar power in Zug was probably also due to the fact that, in contrast to previous years, the electricity generated could be used directly, Weber explains. "It can be used in our own building and as a group of several buildings, for example, in the Association for Self-Consumption (ZEV: Zusammenschluss zum Eigenverbrauch) ."
The canton is setting a good example: over the next five years, with 18 photovoltaic systems being installed on the canton's own buildings. Together, these will generate around two gigawatt hours of solar power. "The most recent example," says Weber, "is the photovoltaic system on the roofs of the Cantonal School of Zug, which was installed during the summer holidays."
Heat or electricity generation
Solar collectors are used to generate heat, i.e. are for thermal use. Solar panels or photovoltaic systems are used to generate electricity.
An annual consumption of around 4,500 kilowatt hours is typical for an average Swiss 4-person household in their own home.