The issue. The Swiss Federal Office of Energy (SFOE) has estimated the potential of wind energy, among other things on the basis of measurements and model calculations on the speed, stability and direction of the winds. The wind atlas shows to an accuracy of 100 metres where the worthwhile areas lie. Before the vote on the Energy Strategy 2050 in May 2017, optimism prevailed on the basis of wind data from 2016.
Wide areas from Lake Geneva to Vaud, the Jura heights, Freiburg and Bern to Thurgau appeared in the atlas in dark blue and violet with mean wind speeds of 5.5 to 6.5 metres per second. In the Valais and Grisons Alps, the atlas showed numerous red and dark red areas with 7 to 8 metres per second.
Wind map - 2016
Since a few weeks a new, updated wind atlas is online, and here you can see a rather sobering picture. The red areas with strong winds have practically disappeared into thin air, and instead of violet and dark blue, medium and light blue now dominate.
Wind map - 2019
”Compared to the 2016 edition, the Wind Atlas 2019 shows slightly lower wind speeds in most regions”, stated the BfE when it was published. On the other hand, the spatial distribution of wind resources remains practically unchanged. And it is still true that in many regions of Switzerland the wind is so strong and regular that it can be used to produce electricity.
However, it is now difficult to determine to what extent speeds are shrinking and where the biggest corrections have been made, as the comparative map for 2016 has been switched off. A detailed picture can be found in a November report by Energie Schweiz on updating the wind atlas, which can be found with some effort on the BfE website.
The reasons. In southern central Switzerland and eastern Valais, the speeds in the 2019 version are very similar to those of 2016, it says. In the following regions, however, they are "much lower": in the cantons of Geneva and Vaud, parts of Neuchâtel, western Valais, Misox in Canton Graubünden, the northern region of Canton Graubünden, the southern part of Canton St. Gallen and Canton Thurgau. In the other regions, the differences are 0 to 0.5 metres per second, “although the 2016 version tended to overestimate wind speeds”.
On average, the wind speeds in the new wind atlas are 0.42 to 0.55 metres per second lower than before. They are "significantly lower" in western and eastern Switzerland. "It was known that the values from the Wind Atlas 2016 were too high in these regions," the report says. “The excessive wind speeds were corrected downwards in the update.”
What do the opponents say? The wind power opponents of “Freie Landschaft Schweiz” have called the corrections onto the scene. They consider that new data confirm that wind energy with large turbines is the wrong way to go in Switzerland. They accuse the federal government of exaggerating the potential for 2016 in order to win the vote on the Energy Act 2017. “Before the vote, the BfE looked for ways to sell wind energy as a strong resource that would make it possible to phase out nuclear power”, says Elias Meier, President of the organisation, upon request. Since only 850 plants are feasible in Switzerland and, according to the measurements known at the time, these could not make a significant contribution, “the Wind Atlas 2016 has been massively styled“. After the vote, the withdrawal now follows.
What is the Confederation's response? The Federal Office of Energy (BfE) rejects this. “The updated wind atlas is based on four times more data than the previous version and is therefore a more accurate basis for the cantons and private companies. It provides clues for planning. For a location decision to be made, the data would still have to be supplemented with measurements at the specific location. In fact, the refined measurements have resulted in slightly lower wind speeds on average nationwide”, says Frank Rutschmann, Head of Renewable Energies.