Secure supply of electricity in Greater Bern: Swissgrid strengthens Bassecourt – Mühleberg line


Swissgrid is modernising and strengthening the transmission line between Bassecourt (JU) and Mühleberg (BE). The line is part of the «Strategic Grid 2025» and will secure the supply for Greater Bern when the Mühleberg power plant will be shut down in 2019. In late August, Swissgrid will inform the local population during two information evenings.

The reinforcement of the Bassecourt – Mühleberg extra high-voltage line is part of the «Strategic Grid 2025» and one of Swissgrid's central grid projects. The voltage increase from 220 to 380 kilovolts (kV) and the installation of a transformer will guarantee the power supply in Greater Bern after the Mühleberg nuclear power plant is decommissioned at the end of 2019. The feed-in of 370 megawatts (MW) that will be lost as a result will be compensated through electricity imports and transformation of the imported energy to a lower voltage level. The transformer (380-/220 kV) in Mühleberg will also strengthen the infrastructure and increase the feed-in amount for Greater Bern.

The voltage increase is necessary in order to guarantee the medium-term import capacity and grid stability. This can be seen from the tense energy and grid situation in the winter of 2015/2016. On 30 June 2017, Swissgrid submitted the planning approval dossier for the voltage increase of the Bassecourt – Mühleberg line to the Federal Inspectorate for Heavy Current Installations (ESTI). Given a smooth procedural and project flow, Swissgrid will put the reinforced line into operation at the end of 2019.

Expansion of the existing route

The line will be modernised along the existing pylons and will not change the landscape. Construction work is planned on only 54 of a total of 142 pylons: individual pylon foundations will be reinforced, double anchor chains will be installed, or the cable winch tension will be increased. The future operation at 380 kilovolts will result in an increase in noise emissions that will be hardly noticeable. The emissions will remain within the statutory planning limits. Compliance with the applicable limits of the Noise Abatement Ordinance (NAO) is thus ensured. Thanks to technical measures taken for the existing line, the noise has already been minimised.

Already approved for 380 kilovolts when built in 1978

The Bassecourt – Mühleberg extra-high-voltage line has a length of 45 kilometres and was built in 1978. It was approved and built for an operating voltage of 380 and 220 kilovolts per circuit. Since then, the 380-kV circuit has been operated with 220 kV and the 220-kV circuit with 132 kV. The circuit operated with 220 kV is to be equipped for power transmission with 380 kV. The voltage increase will take place in compliance with the limits specified in the Ordinance on Protection against Non-Ionising Radiation (NISV).

Swissgrid in dialogue with the population

Dialogue with the population, municipalities, authorities and associations is very important to Swissgrid. From 14 September to 13 October 2017, the project will be publicly disclosed in the affected municipalities. Prior to the public disclosure, Swissgrid will inform the local population about the project and answer questions. The first information event will take place today from 6 to 9 pm in Lyss, and the second will he held on 31 August 2017 in Tavannes, also from 6 to 9 pm.