Where tradition meets innovation

Switzerland – After nearly nine decades of continuous operation, the Klingnau hydropower plant on the River Aare in Switzerland is set to undergo a full-scale modernization. As one of the important hydropower stations in the country, Klingnau plays a vital role in the region’s electricity supply. Now, its next chapter is about to begin.

The Swiss arm of international technology group ANDRITZ has secured a major contract to refurbish Klingnau’s turbines. The project, commissioned by Aarekraftwerk Klingnau AG — a joint venture owned by Axpo (60%) and AEW Energie AG (40%) — marks a significant investment in the long-term sustainability of one of Switzerland’s key hydroelectric assets.

First commissioned in 1935 in the canton of Aargau, the 43 MW Klingnau plant is nearing its 90th year of operation and is due for a comprehensive modernization. Over the next six years, all three of its vertical, double-regulated Kaplan turbines will undergo a full general overhaul. The goal: to improve efficiency, extend service life, and boost power generation by 11%.

Once the refurbishment is completed, in 2032, the plant is expected to generate around 210 GWh annually — enough to power 55,000 four-person households. This is around 3,000 more than before.

A historic plant at a strategic location

Klingnau is the last hydroelectric facility on the River Aare before it flows into the High Rhine near Koblenz. Fed by the Klingnau reservoir, now a protected nature reserve, it is one of the most important stations along the Aare’s eleven-step cascade. This cascade, which runs between Lake Biel and the Rhine, allows a 100 m elevation drop to be harnessed for clean energy.

Two of the original turbine units were supplied by Escher Wyss — now ANDRITZ — making ANDRITZ not only the original OEM supplier but also the chosen contractor for the refurbishment of the three vertical, double-regulated Kaplan turbines and auxiliary systems. ANDRITZ’s Swiss team will manage the entire refurbishment project, including planning, logistics, turbine disassembly and reassembly, and commissioning.

A comprehensive overhaul 

The scope of supply and services provided by ANDRITZ for the refurbishment includes design, engineering, manufacturing of new parts, workshop refurbishment, transport, installation, testing, and commissioning. Highlights include homologous model testing, the supply of new Kaplan runner blades, new oil supply systems, and upgrades to the auxiliary operating units. Additional components to be refurbished or partially renewed include guide vanes and guide vane rings, wicket gates and their control systems, turbine shafts (including FEM calculations), runner hubs, runner casings, turbine covers, draft tube linings, aeration valves, and more.

Model testing will be carried out at ANDRITZ’s state-of-the-art test rig in Linz, Austria. Manufacturing of the new Kaplan runner blades and the refurbishment of the large turbine components will take place in Graz, Austria.

Supporting Switzerland's energy future

This project aligns with the goals of the Swiss Energy Strategy 2050, which promotes renewable energy and aims to reduce CO2 emissions. By enhancing the efficiency of an existing plant, the Klingnau refurbishment helps meet increasing demand for clean electricity without building new infrastructure.

ANDRITZ is deeply rooted in Switzerland’s energy landscape. Roughly 90% of the country’s installed hydropower turbines were originally supplied or refurbished by ANDRITZ or its predecessor companies. The Klingnau contract underscores ANDRITZ’s ongoing commitment to supporting the Swiss hydropower sector with a full range of technology and services.

Author: Marco Turnell