Articles | Volume 11, issue 5
https://doi.org/10.5194/wes-11-1553-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wes-11-1553-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Reliability and O&M key performance indicators of onshore and offshore wind turbines based on field-data analysis
Julia Walgern
CORRESPONDING AUTHOR
Fraunhofer Institute for Wind Energy Systems IWES, 30159 Hannover, Germany
University of Strathclyde, 16 Richmond St, Glasgow G1 1XQ, United Kingdom
Nils Stratmann
Fraunhofer Institute for Wind Energy Systems IWES, 30159 Hannover, Germany
Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany
Martin Horn
Fraunhofer Institute for Wind Energy Systems IWES, 30159 Hannover, Germany
Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany
Nathalene W. Y. Then
Fraunhofer Institute for Wind Energy Systems IWES, 30159 Hannover, Germany
Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany
Moritz Menzel
Fraunhofer Institute for Wind Energy Systems IWES, 30159 Hannover, Germany
Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany
Fraser Anderson
Fraunhofer Institute for Wind Energy Systems IWES, 30159 Hannover, Germany
Fraunhofer UK Research Ltd., 99 George St., Glasgow G1 1RD, United Kingdom
Athanasios Kolios
University of Strathclyde, 16 Richmond St, Glasgow G1 1XQ, United Kingdom
Technical University of Denmark, Department of Wind & Energy Systems, Risø Campus, Frederiksborgvej 399, 4000 Roskilde, Denmark
Katharina Fischer
Fraunhofer Institute for Wind Energy Systems IWES, 30159 Hannover, Germany
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Timo Lichtenstein, Martin Hippenstiel, and Katharina Fischer
Wind Energ. Sci., 11, 1963–1970, https://doi.org/10.5194/wes-11-1963-2026, https://doi.org/10.5194/wes-11-1963-2026, 2026
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Power converter faults in wind turbines often lead to costly downtime and repeated maintenance. We present a practical, explainable, and fully data-driven approach that utilizes high-resolution converter control system records, 1 min operating data, and event logs to predict whether a fault leads to a long or short standstill. By combining engineered features with interpretable feature reduction, we achieve 89 % accuracy and an F1 score of 0.86, providing support for remote decision-making.
Bruno Rodrigues Faria, Nikolay Dimitrov, Nikhil Sudhakaran, Matthias Stammler, Athanasios Kolios, W. Dheelibun Remigius, Xiaodong Zhang, and Asger Bech Abrahamsen
Wind Energ. Sci., 11, 1583–1606, https://doi.org/10.5194/wes-11-1583-2026, https://doi.org/10.5194/wes-11-1583-2026, 2026
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This study presents continuous lifetime assessments of wind turbine structural (tower) and rotating components (main bearings) over nearly a decade, combining controller data, calibrated load measurements, and a virtual load sensor at the tower bottom. The components' estimated lifetimes exceeded the design lifetime. Contrary to expectations, lower turbulence intensity at rated wind speed increased fatigue loads of the locating main bearing due to turbulence averaging.
Carlo L. Bottasso, Sandrine Aubrun, Nicolaos A. Cutululis, Julia Gottschall, Athanasios Kolios, Jakob Mann, and Paul Veers
Wind Energ. Sci., 11, 347–348, https://doi.org/10.5194/wes-11-347-2026, https://doi.org/10.5194/wes-11-347-2026, 2026
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This editorial celebrates the 10th anniversary of Wind Energy Science, reflecting on a decade of rapid scientific progress and the journal’s role in advancing fundamental, interdisciplinary research. It highlights key developments in wind energy, the importance of open science and academia–industry collaboration, and emerging challenges such as data sharing and artificial intelligence. Above all, it honors the research community that has shaped the journal and looks ahead to the next decade.
Moritz Johann Gräfe, Azélice Ludot, Matt Shields, Athanasios Kolios, Rajasekhar Pulikollu, and Nikolay Dimitrov
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2026-31, https://doi.org/10.5194/wes-2026-31, 2026
Preprint under review for WES
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This study examines the risk drivers of the economic success of wind energy projects and how interacting risks threaten that success. We combined expert opinions, survey results, and literature findings to identify key challenges in planning and operation. The results show that risks interact and can cause uneven financial losses, highlighting the need for integrated decision support tools.
Innes Murdo Black, Moritz Werther Häckell, and Athanasios Kolios
Wind Energ. Sci., 10, 2889–2901, https://doi.org/10.5194/wes-10-2889-2025, https://doi.org/10.5194/wes-10-2889-2025, 2025
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Population-based structural health monitoring minimises costs by efficiently sharing information within a wind farm, reducing the need for many sensors and model updates.
Büsra Yildirim, Nikolay Dimitrov, Athanasios Kolios, and Asger Bech Abrahamsen
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2025-115, https://doi.org/10.5194/wes-2025-115, 2025
Revised manuscript not accepted
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A surrogate-based design optimization framework has been implemented for a floating wind turbine. By integrating surrogate modeling and analytical design constraints, computationally efficient exploration of design spaces is ensured. This integration provides a connection between conceptual and detailed design. The proposed methodology achieved a reduction of 3.7 % in the Levelized Cost of Energy, considering ultimate, fatigue, and serviceability limit states.
Azélice Ludot, Thor Heine Snedker, Athanasios Kolios, and Ilmas Bayati
Wind Energ. Sci. Discuss., https://doi.org/10.5194/wes-2024-162, https://doi.org/10.5194/wes-2024-162, 2025
Preprint withdrawn
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This paper presents a methodology to develop machine learning models designed to predict, in real-time, hourly fatigue damage accumulation in the mooring lines of floating wind turbines, from measurements of five environmental variables: wind speed, wind direction, wave height, wave period, and wind-wave misalignment. The proposed tool is intended for predictive maintenance applications, which has been identified as a key area for cost reduction in floating wind.
Mareike Leimeister, Maurizio Collu, and Athanasios Kolios
Wind Energ. Sci., 7, 259–281, https://doi.org/10.5194/wes-7-259-2022, https://doi.org/10.5194/wes-7-259-2022, 2022
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Floating offshore wind technology has high potential but still faces challenges for gaining economic competitiveness to allow commercial market uptake. Hence, design optimization plays a key role; however, the final optimum floater obtained highly depends on the specified optimization problem. Thus, by considering alternative structural realization approaches, not very stringent limitations on the structure and dimensions are required. This way, more innovative floater designs can be captured.
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Short summary
This study analyses maintenance data from over 1000 onshore and offshore wind turbines, covering 4200 operating years, to assess failure rates, repair times, and maintenance needs. It compares failure rates per turbine and per megawatt, examines time-dependent failure behaviour, and evaluates maintenance interventions. Results show higher onshore failure rates and identify the pitch, control, and converter systems as most critical.
This study analyses maintenance data from over 1000 onshore and offshore wind turbines, covering...
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