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New methods enable a more flexible hydropower

Published: 26 April 2021

Hydropower is used to balance the Swedish power grid, but the role as regulating power entails great wear and tear on the turbines because they are often run at operating points for which they are not designed. As part of the work to enable a more flexible hydropower, researchers at Luleå University of Technology are now investigating two new methods for reducing wear on water turbines when they are used as regulating power.

− The new methods we develop will lead to increased performance and production flexibility, which in turn enables better integration of intermittent renewable energy. We also envisage a reduced environmental impact by improving the use of water, says Michel Cervantes, professor in fluid mechanics at Luleå University of Technology.

The objective of AFC4Hydro is to design, implement and validate in full-scale hydraulic turbine an active flow control system that permit to increase efficiency and reduce the dynamic loads on the structure at any off-design operating conditions and during transient operations. The implication of the term active is that some physical quantity like pressure, strain or vibration will be measured online, and if the level of this signal is above some threshold value, a flow control system will be activated. 

A challenging project

− A unique feature of this project is that the control system will be validated at four different scales; ranging from a 50 Watt turbine at LTU, to a 200 Megawatt turbine in Norway over the project period, says Michel Cervantes and continues.

− The project will enable the water turbines to run with a more varied flow. This should optimize the use of water resources and contribute positively to the effects of climate change. Our research aims to reduce the pressure fluctuations, the induced loads on the structure and the vibration levels in off-design. As a result, the life of the turbines will increase and the costs of improving their performance will decrease.

Close collaboration between academia and industry

A novel method to mitigate the adverse effects of off-design operation is being developed at Luleå University of Technology in which water is being injected into the turbine’s draft tube.

− Until now, the developed control system to minimize pressure pulsations in hydropower has been passive and mainly dealt with consequences, not causes. Our method aims to control instability that develops in the turbine by manipulating the flow in an active way and thereby remedy the cause of the pressure pulsations directly, says Michel Cervantes.

The development takes place in close collaboration with Universitat Politecnica de Catalunya (Spain), Flow Design Bureau (Norway), Vattenfall and Porjus hydropower foundation (Sweden) and Statkraft (Norway). The project started in fall 2019, and currently, measurements are being performed at the LTU model turbine.
The project has been granted 16 million SEK from Horizon 2020 but is also funded by Luleå University of Technology, Vattenfall and Statskraft. The work involves eight employees at two departments at Luleå University of Technology.


Michel Cervantes

Cervantes, Michel - Professor

Organisation: Fluid Mechanics, Fluid and Experimental Mechanics, Department of Engineering Sciences and Mathematics
Phone: +46 (0)920 493014