Rellswerk in Vandans, the latest pumped storage power plant by Vorarlberg-based Illwerke AG, has been on the grid since the middle of last year.

The facility functions as an important part of the Obere Ill-Lünersee complex by contributing a significant share of the peak energy and regulating power generated at the Lünerseewerk. The operators invested around € 38 million in the project, which was implemented with considerable effort over the last three years. Rellswerk is equipped with a modern reversible pump turbine, which is designed for an output of 15 MW in pumped mode and 12 MW in turbine mode. The power station pumps around 17 million m3 of water into the Lünersee every year. Facilities like the Lünerseewerk play an important role in mitigating and compensating for fluctuations in the grid that are caused by the volatility of wind and solar energy.