Axpo inspecting cable network of Horgen-Wädenswil high-voltage line

05.10.2017 - Axpo has reassessed the voltage conversion project for the 8.2-km long high-voltage line between Horgen and Wädenswil (ZH). Axpo is currently inspecting the entire cable network between Horgen and Wädenswil in connection with the Electricity Grid Strategy currently under debate in the Swiss Parliament.

The high voltage grid south of Zurich ensures electricity supply to the towns on the left bank of the Lake of Zurich. Axpo is planning to convert the line between the Horgen substation and Wädenswil from 50 kilovolts (kV) to 110 kV in order to provide reliable, sustainable energy supply in this region. Conversion will increase transmission capacities and reduce grid losses by 75 per cent. In 2016, Axpo initiated a planning approval process with the Swiss Federal Inspectorate for Heavy Current Installations (ESTI) for the necessary construction measures including the partial cabling of the route between Horgen and Wädenswil. It was planned to leave the overhead line between Hanegg (mast 30) and the Wädenswil substation in place with just some minor structural adjustments to the masts.

In view the approval of the Electricity Grid Strategy, Axpo has suspended the current planning approval procedure as of the end of September 2017 until further notice. According to the new strategy, distribution grid lines must be placed under ground when possible and if the costs in comparison to a new or modified overhead line do not exceed a factor (3.0 at the highest) to be determined by the Federal Council.

The changed political and regulatory requirements prompted a reassessment of the project. New electrical insulation of the existing Horgen-Wädenswil overhead line would require major structural measures. In comparison, the additional costs for new, state-of-the-art cabling are lower by a factor of three.

As a result, Axpo is reviewing the possible installation of new underground cabling on the entire route between the Horgen and Wädenswil substations taking into account technical, economical, spatial development, and environmental aspects. 

The review will take several months to complete. Thanks to regular inspection and optimisation of its grid structure and grid projects Axpo ensures the reliability of the power gird at low grid tariffs.