Grid project Innertkirchen – Ulrichen

The 27-kilometre-long line section between Innertkirchen (BE) and Ulrichen (VS) is to be replaced and increased from 220 to 380 kilovolts. Swissgrid has developed various technically feasible planning corridors. They include both overhead line and cable variants. The multifunctional Grimselbahn Tunnel is one of these cable variants.

Your contact for this grid project

Jan Schenk
Jan Schenk

Phone +41 58 580 21 11
info@swissgrid.ch

Planning area
Planning area
Existing line
Existing line
Substation
Substation

Overview

  • Most of the line between Innertkirchen and Ulrichen is over 60 years old and must be brought into line with the current state of the art.
  • As part of the modernisation, the line will be prepared for an increase in voltage from today’s 220 kV to 380 kV. This is necessary to ensure that the growing electricity production from hydroelectric power in Ticino, Valais and Bern is transported to Central Switzerland.
  • For the replacement of the extra-high-voltage line between Innertkirchen and Ulrichen, the monitoring group appointed by the Swiss Federal Office of Energy (SFOE) recommends an underground cable between Innertkirchen and Oberwald and an overhead line between Oberwald and Ulrichen. The un-derground cable will be installed either in existing and new tunnels or in the multifunctional Grimsel-bahn tunnel.
  • The project is undergoing the federal government’s sectoral planning process for transmission lines (SÜL). Following public consultation, the Federal Council will define the planning corridor and transmission technology. This decision is expected to be made at the end of 2022. Swissgrid will then kick off a construction project.

Project description

Initial situation

Most of the extra-high-voltage line between Innertkirchen and Ulrichen, which covers a distance of 27 kilometres over the Grimsel Pass, is over 60 years old and must be brought into line with the current state of the art. The modernisation will also encompass an increase in voltage from the existing 220 kilovolts (kV) to 380 kV throughout. The increase in the capacity of the line between Mettlen (LU) and Ulrichen is an important project in Swissgrid’s «Strategic Grid 2025».

Why the project is necessary

The expansion of electricity production from hydropower is a central pillar of the Energy Strategy 2050. The replacement and increase in voltage of the line between Innertkirchen and Ulrichen is important for the transportation of the growing electricity generation from the cantons of Bern, Valais and Ticino to the conurbations in Central Switzerland. The distribution of energy flows along several north-south axes also increases grid stability. The increase in capacity is necessary in light of the federal government’s energy strategy, in order to transport the increasing electricity production from hydropower in the cantons of Bern, Valais and Ticino to Central Switzerland and to permanently enhance security of supply throughout Switzerland.

Sectoral planning process for transmission lines (SÜL)

At the start of July 2020, Swissgrid submitted an application to establish a planning corridor between Innertkirchen and Ulrichen to the Swiss Federal Office of Energy (SFOE) in the federal government’s sectoral planning process for transmission lines (SÜL). As a first step, Swissgrid developed a range of possible corridors, i.e. geographic areas in which a route can be established with a certain transmission technology – overhead line or underground cable – during the further course of the project.

Each of the variants has specific advantages and disadvantages with respect to regional planning, the environment, technology and economic viability. The SFOE set up a monitoring group to assess and evaluate these aspects as objectively as possible. This monitoring group incorporated various federal offices, the Swiss Foundation for the Protection of the Landscape, the cantons of Valais and Bern, and Swissgrid. The monitoring group examined and evaluated a total of six corridor variants based on 39 criteria on the topics of «spatial development», «environment», «technology» and «economic viability».

Monitoring group proposal

The monitoring group’s recommendation to the SFOE consists of an underground cable between Innertkirchen and Oberwald and an overhead line between Oberwald and Ulrichen. There are two variants for the underground cabling between Innertkirchen and Oberwald, which will cover a distance of around 23 kilometres.

«Long cabling 2-A variant (tunnel variant)»

«Long cabling 2-A variant (tunnel variant)»

  • This variant features a long underground cable with new and existing tunnels. The transmission line will run through a new cable tunnel between the Innertkirchen substation and Handegg. Between Handegg and the Grimsel 2 power plant, the line will be laid in existing tunnels belonging to Kraftwerke Oberhasli. Between the Grimsel 2 power plant and Oberwald, the line will be again be routed underground in a new cable tunnel that is still to be built.
  • In Oberwald, the line crosses the valley floor as an underground cable approximately 10 metres below the surface. A transition structure is planned on the south side of the valley south-west of the construction zone in Unterwassern, a part of the village of Oberwald. From there, the transmission line will run as an overhead line along the south side of the valley before reaching the existing line above the Nufenen Pass in the Ulrichen area.
«Long cabling 2-A multifunctional Grimselbahn tunnel» alternative variant

«Long cabling 2-A multifunctional Grimselbahn tunnel» alternative variant

  • For the multifunctional Grimselbahn tunnel variant, the transmission line will be laid in the Grimsel tunnel. This tunnel stretches from Innertkirchen to Oberwald. The line is located in a separate cable tunnel that runs parallel to the railway tunnel.
  • In Oberwald, the line crosses the valley floor as an underground cable approximately 10 metres below the surface. A transition structure is planned on the south side of the valley south-west of the construction zone in Unterwassern, a part of the village of Oberwald. From there, the transmission line will run as an overhead line along the south side of the valley as far as Ulrichen where it will reach the existing line above the Nufenen Pass.

Tunnel or multifunctional Grimselbahn tunnel?

If the Federal Council accepts the recommendation of the monitoring group, a decision will subsequently have to be made as to whether the tunnel variant or the multifunctional Grimselbahn tunnel variant will be implemented. Various conditions must be fulfilled before the Grimselbahn tunnel variant can go ahead. Firstly, the funding for the railway tunnel must be secured in the national parliament by 2027 at the latest. Secondly, a construction permit will be required by 2030 at the latest. If both conditions are met – in addition to the operating and technical requirements – the extra-high-voltage line will run through the tunnel parallel to the Grimselbahn tunnel. Otherwise, the line will follow the route set out for the tunnel variant. According to the latest plans, the extra-high-voltage line should become operational around the middle of the 2030s.

Swissgrid is aware of the advantages of bundling large, linear infrastructures, particularly in the area of landscape protection. It examines the corresponding synergy potential in all line projects. With the proposal to combine a railway tunnel and an underground cable, a variant on the Grimsel is now available that is technically feasible and is suitable for approval. Grimselbahn AG has demonstrated this in a feasibility study (2015) and in an in-depth technical analysis (2019). Further information: www.grimseltunnel.ch

Significant relief for residential areas

All the corridor variants submitted by Swissgrid have one thing in common: they reduce the burden on residential areas in and around Innertkirchen, Guttannen and Obergesteln. Today’s 220 kV line runs partly through the middle of these villages and restricts their development. National and international protected areas will be preserved. These include the Bernese High Alps and Aletsch-Bietschhorn area of national importance that is protected by the Federal Inventory of Landscapes and Natural Monuments of National Importance (ILNM), the Grimsel mire landscape included in the Federal Inventory of Mire Landscapes, and the Jungfrau-Aletsch UNESCO World Heritage Site. The current line will be removed in all variants.

Heutige Leitungsführung in Guttannen (BE)
Existing overhead line routing in Guttannen (BE)

Next steps

In the second half of June 2022, the two variants will continue on to the public consultation stage for three months. After evaluating the submissions, the SFOE will make a final recommendation to the Federal Council. The Federal Council – on the basis of the monitoring group’s recommendation and the results of the consultation – is expected to decide on the planning corridor and the transmission technology between Innertkirchen and Ulrichen at the end of 2022. Swissgrid will then draw up a corresponding construction project.

Schedule in the best case scenario. If it comes to legal proceedings, the timetable will be delayed by two to four years.

Further grid projects in the Haslital Valley

Swissgrid is planning a new line lead-in into the Innertkirchen substation to relieve the village of the current overhead lines. In addition, Swissgrid has replaced the outdated outdoor switching substation in Innertkirchen with a modern gas-insulated switchgear (GIS).

Innertkirchen lead-in

As is well known, Swissgrid is planning a new line lead-in into the Innertkirchen substation to relieve the village of the three current overhead lines. According to the SFOE, the line lead-in will now be included in the Innertkirchen – Mettlen (LU) sectoral planning process in order to avoid any delays. Three variants are currently being examined. According to the current planning, the new line route will be in place by the end of 2028. The dismantling of existing lines is scheduled for 2029.


Renovation of Innertkirchen substation

Swissgrid commissioned a 220 kV modern, gas-insulated switchgear (GIS) in the Innertkirchen substation in September 2020 following a construction period of around two years. Nine line bays, two transformer bays, two longitudinal separations and a cross-coupler form the core of the new 220 kV plant. The switchgear was prepared for all technical variants of the new line from Innertkirchen (underground cable or overhead line). Housed in the building of the substation, the modern GIS system replaces the outdated outdoor switching substation, which further relieves the burden on Innertkirchen’s landscape.

The substation in Innertkirchen is an important grid node in the Swiss transmission grid. It is very important for security of supply in Central Switzerland as well as for regional supply. The switchgear serves as the feed-in point for the Oberhasli power plant.

Erneuerung der Schaltanlage Innertkirchen

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