Therwil: Construction of new high-voltage transformer station

At the beginning of November 2010, construction work started on a new 220/145/50-kV substation in Therwil (BL). Alpiq Grid Ltd. Gösgen is building the facility in conjunction with its partners IWB and EBM. The old Froloo substation, which is still in operation after more than 50 years, will be demolished.

On 1 November 2010, under the lead of Alpiq Netz Ltd. Gösgen, construction work was started on a new 220/145/50-kV substation in the municipality of Therwil, canton Basel-Land. The facility will replace the Froloo open-air substation which has been operating since 1958 and for more than 50 years has been one of the most important feed-in points in the Basel region, supplying the two regional electricity utilities Elektra Birseck Münchenstein (EBM) and Industrielle Werke Basel (IWB).

7,000 square meters to be rehabilitated The new substation is to be built above the municipality of Therwil. The joint project between Alpiq, IWB and EBM will leverage synergies in terms of land, planning, technical installations and maintenance. The new technology built into the substation will reduce the surface area required to only 15 percent of the area covered by the old installation. Demolition of the old substation will free up around 7,000 square meters of land in the Bruderholz recreation area, roughly corresponding to the size of a football pitch. This area will be rehabilitated.

Construction work will last until 2014 The planning for the new substation began in the summer of 2009. In the first phase, between now and the autumn of 2012, the existing 220- and 150-kV switchgear will be replaced by modern, gas-insulated switchgear. The second phase, completed by 2014, will involve the installation of a 50-kV switching station, also featuring gas insulation technology. All installations such as switchgear, transformers and protection/control systems and equipment will be housed in a new building. The substation will no longer use loud pneumatic systems and be able to operate with zero noise emissions.