Switzerland’s national sustainable energy strategy and the resulting growth in hydroelectricity generation in the cantons of Berne, Valais, and Ticino require a significant increase in electricity transmission capacities, particularly to transport green energy to the Swiss Central Plateau and to ensure long-term security of supply throughout the country. This requires the upgrade of existing lines to 380kV and the construction of new high-capacity lines. One example of this is the 220kV line from Innertkirchen in the district of Interlaken-Oberhasli (canton of Bern) to Ulrichen/Obergoms in the district of Goms (canton of Valais), most parts of which are over 60 years old.
To maintain a secure connection between Haslital and Obergoms in the future, the Swiss transmission system operator (TSO) Swissgrid has developed various planning corridors for the construction of a new extra-high voltage line and submitted them to the Swiss Federal Office of Energy (FOE). The TSCNET shareholder has defined three main corridors, some of which include sub-corridors: The first option is a pure overhead line, which crosses high alpine terrain in parts. The second is partial cabling. Here, the middle section is implemented as underground cables, mainly in existing tunnels up to Obergoms. The third variant provides for underground cabling almost exclusively. Either in a new, yet to be built tunnel and then, as in the second alternative, in largely existing tunnels – or in the proposed multifunctional Grimsel Tunnel (envisaged for rail transport and power transmission). If the tunnel is used, the corridor variants for the last section to Ulrichen are possible as overhead line or underground cable .
Each of the submitted options has specific advantages and disadvantages in terms of spatial planning, environment, technology, and economic efficiency. What they all have in common is the relief of settlements in the affected area, where overhead lines currently run partly through villages. The FOE is now discussing and evaluating the planning corridors. Its recommendation will then be submitted to public consultation, and the Swiss Federal Council is expected to determine the planning corridor and transmission technology between Innertkirchen and Ulrichen at the end of 2022.