Performance evaluation of a variable-speed contra-rotating pump-turbine for low-head pumped hydro energy storage

An experimental study

authored by

Ruben Ansorena Ruiz, David Schürenkamp, Daan P.K. Truijen, Justus P. Hoffstaedt, Antonio Jarquin Laguna, Jonathan Fahlbeck, Håkan Nilsson, Melvin Joseph, Mehrdad Zangeneh, Jeroen D.M. De Kooning, Jonas Oldeweme, Heiko Schwarz, Nils Goseberg

Abstract

Pumped Hydro Energy Storage (PHS) provides over 90% of the global long-duration energy storage capacity, yet many regions lack the steep terrain required for conventional high-head PHS. Low-head pumped hydro energy storage (LH PHS) systems address this gap in flat topographic regions but requires efficient pump-turbine technology for operation at variable low heads. This study investigates the use of a variable-speed contra-rotating pump-turbine (CR RPT) for LH PHS applications, presenting experimental results from a model-scale test rig stablished at Technische Universität Braunschweig. This test rig uses two open water surface tanks to provide head, unlike conventional hydraulic test rigs that use pumps. The CR RPT achieved hydraulic efficiencies over 80% for a wide range of operating conditions, peaking at 86.1% and 88.4% for pump and turbine modes, respectively. Additionally, dimensionless analysis revealed that the CR-RPT occupies a unique place in the market and that it achieves the largest power density among comparable hydraulic machines, facilitating greater power output and thus streamlining mechanical and civil engineering requirements for LH PHS.

Organisation(s)

Coastal Research Centre

External Organisation(s)

Technische Universität Braunschweig
Ghent University
Flanders Make
Delft University of Technology (TU Delft)
Chalmers University of Technology
Advanced Design Technology Ltd.

Type

Article

Journal

Energy Conversion and Management: X

Volume

26

ISSN

2590-1745

Publication date

04.2025

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Renewable Energy, Sustainability and the Environment, Nuclear Energy and Engineering, Fuel Technology, Energy Engineering and Power Technology

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://doi.org/10.1016/j.ecmx.2025.101009 (Access: Open)