Capacity at the Rüchlig hydroelectric project in Aarau, Switzerland has been raised by about 10% following an extensive refurbishment project, technology group Voith has announced.

In mid-June 2015, the country’s state-owned energy group Axpo and Voith joined with other suppliers to celebrate the plant’s official opening following a construction phase of around three and a half years. With its new capacity of 11MW, the modernized run-of-river power plant on the Aare river will be capable of generating approximately 64 GWh/year.

"As a result of the upgrades we have increased the capacity of the existing bulb turbines by more than 25%, primarily due to the significantly higher water flow through the turbines. The total output of the power plant could therefore be increased by around 10%," said Rolf Geissberger, Axpo’s project manager responsible for the plant’s electromechanical systems.

In the main powerhouse, Voith modernized the electromechanical equipment of the existing three Kaplan bulb turbines and built a new, structurally identical power unit. The company also supplied the gear units, generators, turbine governors and a specially developed cooling water system. The three existing vertical power units were eliminated as a result of installing two additional flood relieve gates.

Despite a tight schedule and restricted working times due to noise emission constraints, Voith was able to connect the last machine to the grid one month earlier than planned.

The hydropower facility at Rüchlig has been in existence since the 1920s. Following expiry of the concession in 2011, its current operator Axpo decided to undertake a comprehensive upgrade. As a result of the modernization, the plant is now licensed for electricity production until the end of 2074. The plant now meets stringent environmental standards, with fish friendly turbines installed to allow fish passage.

Image: The scope of supply included a new cooling water system in addition to the four primary machines.