The Eurospider team set off for the Grimselwelt in beautiful fall weather. We took the Postbus through the picturesque Haslital valley to the Grimsel Hospiz. The guide from Kraftwerke Oberhasli AG (KWO) was waiting for us there to tell us exciting things about the world of power generation and storage. Alongside Emossen and Linth-Limmern, Grimsel is one of the largest pumped storage power plants in Switzerland, which can compensate for electricity shortages and oversupply (e.g. from photovoltaics). He also reported on the complexity of raising the new dam wall. After the tour and a small snack, we continued on foot up to the Gelmer dam. The Grimsel Railway, the steepest funicular in Europe, took us back down to the valley in spectacular style.