Precise weather forecasts are an important prerequisite for the efficient and economical operation of solar installations and wind farms. One of the reasons why MET Group decided to acquire a 25% stake in SwissWinds was the analysis of the weather and wind situation in Switzerland.
Author: Vasilis Pappas, Senior Meteorologist, MET Group
Vasilis Pappas is the Senior Meteorologist at MET Group. He studied Physics and Meteorology in Greece and Great Britain and held various positions in the energy sector and in academia in Great Britain and Germany. He has been working at MET Group’s headquarters in Switzerland for around two years and is responsible for weather analytics at MET Group. Along with the rest of the Analytics team, as well as input from the Power Trading desk, he creates various scenarios for MET Group's renewable energy plants. Vasilis is convinced that the wind conditions in Switzerland favour investments in wind energy.
The situation in Switzerland
Switzerland is unique in terms of its landscape. High mountains with steep slopes in the south, valleys with lakes in central Switzerland and the north-east, and the Jura mountains in the north-west (Figure 1). In terms of wind potential, this results in a complex mosaic of strong and weak wind regions and a wide range of different wind directions.
Proof of the uniqueness of the Swiss landscape are the winds that are characteristic of the region called the Foehn, Bise and westerly winds. The first is a wind which blows through the inner Alpine valleys on the north and south sides of the Alps. The last two are north-easterly and south-westerly winds, respectively, that mainly blow over the Central Plateau.
Figure 1. Map of the mountainous regions of Switzerland 2023 (Source: Wikipedia).
Wind power potential
Most wind turbines are currently installed in western Switzerland (Figure 2). This coincides in part with the windy locations according to the wind atlas of the Swiss Federal Office of Energy 2020 (Figure 3). However, there are still numerous locations with interesting wind power potential on the Central Plateau between the Jura and the northern side of the Alps, in the Foehn valleys north of the Alps, along the Alpine passes and in the south-western regions north and south of the Rhone.
Figure 2. Wind parks in operation. (Source: https://suisse-eole.ch/de/windenergie/windparks/)
Figure 3. Yearly average of the simulated wind speed and wind direction at 125 m above the ground. Source: Windatlas Schweiz.
Measurements and simulations
Simulations of wind speed and wind direction are more difficult for Switzerland than for other, less complex regions, such as northern Germany or the Benelux countries, due to the comparatively complex landscape. Nowadays MET Group, like others, has advanced simulation methods with artificial intelligence that enable it to make well-founded decisions even under complex conditions.
These same methods have already been successfully utilised for MET Group’s wind farms in Bulgaria as well as for other projects that are in planning and construction. The right combination of measurements and simulations is not only important for the planning phase, i.e. for the choice of optimum location, but also for calculating the electricity price, the quantities to be sold and the expected revenue.
In addition, a weather forecast which is as accurate as possible, is important during the operating phase in order to further optimise the yields from the wind farm. Maintenance timing can also be optimally planned with the help of medium and long-term weather forecasts.
Wind power potential is available
So, is it worth investing in wind energy in Switzerland and facing up to the challenges of the complex terrain? There are numerous studies in literature that classify and characterise the variability of wind speed in Europe on the basis of weather regimes. The following figure is taken from one of these studies (Cortesi et al., 2019) and shows the relative wind speed anomalies for each of the four weather regimes (we only show here the winter months from their Figure 4).
This shows that although wind blows stronger in north-west Europe, this is not always the case. It often happens that storms originating in the Atlantic are channelled towards southern Europe. This leads to the well-known autumn and winter storms in westerly weather conditions in Switzerland.
Figure 4. Average (1981-2016) JRA-55 10-m wind speed relative anomalies (in %) for each of the four monthly regimes from December (top row) to February (bottom row). Regimes are shown, from left to right, in decreasing order of average monthly frequency of occurrence (1981-2016). Contour lines show associated SLP anomalies, with a separation of 2 hPa. Bold black lines show null anomalies, while dashed lines show negative ones. Black points indicate areas where anomalies are significantly different from zero (t-test at 99% confidence level). Source: Cortesi, N., Torralba, V., Gonzalez-Reviriego, N., Soret, A., Doblas-Reyes F. J., 2019: Characterization of European wind speed variability using weather regimes, Climate Dynamics 53:4961-4976.
Using the weather statistics, the answer is: Yes, it is worth investing in wind energy in Switzerland too. A supporting fact is that wind power is generated in Switzerland, particularly in winter, when domestic hydropower and solar energy produce less.
Moreover, Switzerland is strongly interconnected with the wider European electricity grid and it is likely that export capacity to Switzerland will increasingly be a limiting factor in winter in Europe in the future due to many thermal power plants shutting down. This means that Swiss wind farms can also contribute to the energy supply when production from renewable energy sources in other countries is low (e.g. during regime 2 in December or regime 4 in January in Figure 4).
Wind power is also an ideal supplement to solar energy from PV systems. Together, they perfectly complement the existing Swiss power plant portfolio of renewable hydropower with the proven run-of-river, pumped and storage power plants.