Complex large hydropower scheme (FLEXSTOR)

FLEXSTOR will test a set of innovative tools for flexible operation of storage hydropower plants in changing environment and market conditions at a complex hydropower scheme. This demostrator is motivated by the main hydropower challenge in Switzerland, namely the need for flexible operation targeting premium remuneration hours, for which comprehensive methodologies for hydropower upgrading projects are still missing.

Specific goals of FLEXSTOR are to demonstrate how to: concentrate production in less hours, while mitigating negative impacts (e.g. river up/down surges); manage reservoir sedimentation to expand storage capacity while complying with the Waters Protection Act; address mountain slope instability risks in periglacial zone, avoiding non-optimal “preventive reservoir lowering”; identify the changing demand structure and the required adaptation of the  storage management; extend the operating range of hydraulic machinery, whilst avoiding instabilities; optimally manage a compensation basin in order to minimize the ecological impacts of hydropeaking in the downstream river reach.

All these developments, which are at the core of the WP2 efforts, will be validated with proof-of-concept in the complex system of KWO Oberhasli, which allows later replication to other hydropwer schemes in Switzerland. The demonstration project has now been approved by CTI and industry (1'360kCHF) and will last till end 2018.

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Partners: EPFL-LCH, all participants to WP2

Media reports

Impulse wave experiment (media visit on 1 October 2018)

Gletschersturz in die Kiesgrube (NZZ, 2 October 2018)

ETH simuliert gefürchtete Wellen in der Kiesgrube (Der Landbote, 2 October 2018)

ETH-Forscher simulieren Bergsturz in einer Kiesgrube in Bülach (Tages-Anzeiger, 2 October 2018)

Tsunami in der Kiesgrube: Grossversuch zu Impulswellen (Spiegel online, 3 October 2018)

Weltweit erster Versuch: ETH simuliert Flutwelle in Kiesgrube (Tages-Anzeiger online, 2 October 2018)

Wissenschafter simulieren Gletschersturz in einer Bülacher Kiesgrube (NZZ online, 2 October 2018)

ETH experimentiert mit 7-Tonnen-Schlitten am Risiko der Stauseen (, 1 October 2018)

Versuchs-Tsunami in Kiesgrube (Zürcher Unterländer online)


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Does Switzerland need more dams and reservoirs? Blog article by Anton J. Schleiss. Available in English, German and French.