VAG EKN® S – the innovative high-performance valves in operation

A significant milestone for Europe’s sustainable energy supply has been reached: In the scope of the Austrian large-scale project Kühtai 2 Pumped Storage Hydropower Station implemented by TIWAG (Tiroler Wasserkraft AG), the newly developed butterfly valves of the VAG EKN® S type will be installed for the first time. The shut-off and safety valves, specially designed for high-performance applications in the hydropower area, set new standards in terms of technology, safety and efficiency – and will demonstrate their strengths in one of Europe’s highest pumped storage hydropower stations in the future.

The new Kühtai storage reservoir is being created in the Tyrolean Alps at an altitude of more than 2,000 metres. Central component of this plant: Two EKN^® S Butterfly Valves made by VAG – each of them DN 4000 PN 15, and provided with high-precision technical equipment. The first butterfly valve was installed in February 2025, the second one followed in May 2025. One of them serves as an isolation valve, the other one as a safety valve designed for reliable emergency shut-off in the event of a pipe burst at a flow rate of 190 m³/s.

The VAG EKN^® S Butterfly Valve is a completely new development based on the proven VAG EKN^® H1200 Butterfly Valve – but specifically adapted to the extreme requirements in hydropower stations. The “S” in its name stands for Special and Speed: It has been designed for extraordinarily high flow velocities at minimal pressure losses. With nominal diameters ranging from DN 800 to DN 5000 and nominal pressures of up to PN 25, the VAG EKN^® S Butterfly Valve covers a wide range of applications.

With its Kühtai 2 Project, TIWAG makes an essential contribution to energy transition – and with its state-of-the-art disk technology, the VAG Group is a central part of it.  The VAG EKN^® S Butterfly Valve ensures safe, precise and maintenance-friendly shut-off even under extreme operating conditions. Its use in the high alpine mountains impressively underlines VAG’s power of innovation and technical excellence.

The VAG Group looks at the Kühtai Project with pride and is looking forward to its further steps – not least because this project sets a clear example of technological innovation and a sustainable energy future.

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