Publikationen

2021

• Application of a New Dispatch Methodology to Identify the Influence of Inertia Supplying Wind Turbines on Day-Ahead Market Sales Volumes

  Thiesen, H. ., & Jauch, C. . (2021). Application of a New Dispatch Methodology to Identify the Influence of Inertia Supplying Wind Turbines on Day-Ahead Market Sales Volumes. Energies, 14(5). http://doi.org/10.3390/en14051255 (Original work published Februar 2021)

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  Power system inertia is an essential part of grid frequency control. The number of synchronously connected machines, which inherently provide inertia, is decreasing due to the transition to renewable energies. Conventional generation units are being replaced by renewable generation units which are connected to the grid via frequency converters. Some power systems already suffer from too little power system inertia. Hence, inertia is a valuable yet non-traded commodity. A day-ahead dispatch methodology to secure power system inertia was developed and is applied and assessed in this work. Day-ahead market data of the combined market of the Republic of Ireland and Northern Ireland is used. If the superimposition of sell and buy bids results in insufficient inertia, the dispatch algorithm is applied. In decreasing price order, non-inertia-providing sell bids get replaced by the following sell bids in the merit order. The iterative process is repeated until sufficient inertia is in the system. The provision of synthetic inertia by wind turbines is considered in the process. The costs for additional stored kinetic energy for the assessed time periods and scenarios result in costs ranging from 1.02 to 4.49 EUR/kgm2.

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  • Personenseiten

    • Thiesen, Henning
    • Jauch, Clemens

  • Abteilung/Einrichtung

    • Wind Energy Technology Institute

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  • 2021
  • Journal Article
  • • Henning Thiesen
    • Prof. Dr. Clemens Jauch

• Capturing shrinkage and neck growth with phase field simulations of the solid state sintering.

  Ivannikov, V. ., Thomsen, F. ., Ebel, T. ., & Willumeit-Römer, R. . (2021). Capturing shrinkage and neck growth with phase field simulations of the solid state sintering. Modelling and Simulation in Materials Science and Engineering, 29(7). http://doi.org/10.1088/1361-651X/ac1f87

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    • Thomsen, Fritz

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  • 2021
  • Journal Article
  • • Vladimir Ivannikov
    • Fritz Thomsen
    • Thomas Ebel
    • Regine Willumeit-Römer

• Grid Services and Stress Reduction with a Flywheel in the Rotor of a Wind Turbine

  Jauch, C. . (2021). Grid Services and Stress Reduction with a Flywheel in the Rotor of a Wind Turbine. Energies, 14. http://doi.org/10.3390/en14092556

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  Wind power penetration increases in most grids and the sizes of wind turbines increase. This leads to increasingly tough requirements, which are imposed on wind turbines, both from the grid as well as from economics. Some of these partially contradictory requirements can only be satisfied with additional control mechanisms in the wind turbines. In this paper, such a mechanism, i.e., a hydraulic–pneumatic flywheel system in the rotor of a wind turbine, is discussed. This flywheel system supports a wind turbine in providing grid services such as steadying the power infeed, fast frequency response, continuous inertia provision, power system stabilization, and low voltage ride-through. In addition, it can help mitigate the stress on the mechanical structure of a wind turbine, which results from varying operating points, imbalances in the rotor, gravitation that acts on the blades, in-plane vibrations, and emergency braking. The study presented in this paper is based on simulations of a publicly available reference wind turbine. Both the rotor blade design as well as the design of the flywheel system are as previously published. It is discussed how the aforementioned grid services and the stress reduction mechanisms can be combined. Finally, it is concluded that such a flywheel system broadens the range of control mechanisms of a wind turbine substantially, which is beneficial for the grid as well as for the wind turbine itself.

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    • Jauch, Clemens

  • Fachbereich

    • Fachbereich 2: Energy and Life Science

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  • 2021
  • Journal Article
  • • Prof. Dr. Clemens Jauch

• \# Covid-19: An Exploratory Investigation of Hashtag Usage on Twitter

  Petersen, K. ., & Gerken, J. M. (2021). \# Covid-19: An Exploratory Investigation of Hashtag Usage on Twitter. Health Policy.

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  • Personenseiten

    • Petersen, Kai
    • Gerken, Jan

  • Abteilung/Einrichtung

    • FLAIR - Flensburg Artificial Intelligence Research

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  • 2021
  • Journal Article
  • • Kai Petersen
    • Jan Gerken

• Arbeiten Frauen aufgrund des Ehegattensplittings weniger? — Eine empirische Untersuchung für Deutschland

  Chirvi, M. . (2021). Arbeiten Frauen aufgrund des Ehegattensplittings weniger? — Eine empirische Untersuchung für Deutschland. Steuer Und Wirtschaft, 98(2). http://doi.org/10.9785/stuw-2021-980207

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  Der Beitrag soll zur Klärung der Frage beitragen, ob das Ehegattensplitting, wie vielfach behauptet wird, einen negativen Einfluss auf das Arbeitsverhalten verheirateter Frauen hat. Hierzu kommt für Deutschland erstmals ein von Quasi-Experimenten inspirierter Ansatz zum Einsatz, bei dem anhand des allgemeinen Effekts der Heirat auf das Erwerbsverhalten der heiratenden Frauen die Wirkung des Ehegattensplittings geschätzt wird. Die Veränderung des Arbeitsverhaltens heiratender Frauen wird dabei der Veränderung bei jenen Frauen gegenübergestellt, die im gleichen Zeitraum weiterhin mit ihrem festen Partner zusammenleben, ohne zu heiraten (Kontrollgruppe). Die Ergebnisse sprechen eindeutig gegen einen unmittelbaren negativen Effekt des Ehegattensplittings auf das Erwerbsverhalten von Frauen. Jedoch reduzieren heiratende und zeitgleich ein Kind bekommende Frauen ihre Erwerbstätigkeit stärker als gebärende Frauen in der Kontrollgruppe. In Folge einer lediglich teilweisen Abschaffung des Ehegattensplittings, die in den Entwürfen zu Parteiprogrammen zur Bundestagswahl 2021 teilweise gefordert wird, sind sogar noch geringere Effekte auf das Arbeitsverhalten zu erwarten.

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    • Chirvi, Malte

  • Fachbereich

    • Fachbereich 4: Wirtschaft

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  • 2021
  • Journal Article
  • • Malte Chirvi

• Implementation of Variable Blade Inertia in OpenFAST to Integrate a Flywheel System in the Rotor of a Wind Turbine

  Alhrshy, L. . (2021). Implementation of Variable Blade Inertia in OpenFAST to Integrate a Flywheel System in the Rotor of a Wind Turbine. Energies, 14. http://doi.org/10.3390/en14102783

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  In this paper, the integration of the dynamic behavior of the flywheel system into the load simulation tool OpenFAST is presented. The flywheel system enables a wind turbine to vary the inertia of its rotor blades to control the power production and, most importantly, to affect the vibratory behavior of wind turbine components. Consequently, in order to simulate the behavior of a wind turbine with a flywheel system in its rotor, the variable blade characteristics need to be considered in the load simulation tool. Currently, computer-aided engineering tools for simulating the mechanical loads of wind turbines are not designed to simulate variable blade inertia. Hence, the goal of this paper is to explain how variable inertias of rotor blades are implanted in such load simulation tools as OpenFAST. OpenFAST is used because of it is free, publicly available, and well documentation. Moreover, OpenFAST is open source, which allows modifications in its source code. This add-on in the load simulation is applied to correct rotor mass imbalance. It can also be applied in many cases related to the change in the inertia of wind turbine rotor blades during its operation as, for example, atmospheric ice accretion on the blades, smart blades, etc.

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  • Personenseiten

    • Alhrshy, Laurence

  • Forschungsprojekt

    • Schwungrad

  • Abteilung/Einrichtung

    • Wind Energy Technology Institute

  • Fachbereich

    • Fachbereich 2: Energy and Life Science

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  • 2021
  • Journal Article
  • • Laurence Alhrshy

• Marine microbial-derived molecules and their potential medical and cosmetic applications )

  Zhang, J. ., Zeng, R. ., & Labes, A. . (2021). Marine microbial-derived molecules and their potential medical and cosmetic applications ). Frontiers in Microbiology, 12, 1965. http://doi.org/10.3389/FMICB.2021.706152

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  • 2021
  • Journal Article
  • • J. Zhang
    • R. Zeng
    • Antje Labes

• Coupled power plant and geostorage simulations of porous media compressed air energy storage (PM-CAES)

  Pfeiffer, W. T., Witte, F. ., Tuschy, I. ., & Bauer, S. . (2021). Coupled power plant and geostorage simulations of porous media compressed air energy storage (PM-CAES). Energy Conversion and Management, 249, 114849. http://doi.org/https://doi.org/10.1016/j.enconman.2021.114849

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  Porous media compressed air energy storage (PM-CAES) systems that use porous geological formations such as sandstone may provide large storage capacities in future energy systems based primarily on fluctuating renewable energy sources. In CAES systems, the instantaneous power and stored energy are closely linked to the storage pressure and the mass flow rate achievable in the geological reservoir. Therefore, a coupled simulator that accurately represents the power plant, the geostorage site, and their interactions during all potential PM-CAES system operation modes is presented in this paper. Using adiabatic and diabatic power plant topology test designs, strong feedback between the achievable storage rates and capacities of the chosen power plant design and geostorage site are found, thus confirming the benefit of this integrated modelling approach. Using a generic, highly cyclic load profile for daily peak shaving with charging and discharging rates of 100 MW and an adiabatic power plant topology, it is found that all discharging targets can be met but the achievable charging rates decrease to approximately 95 MW due to increased pressure in the geostorage after approximately 10 cycles. When a diabatic power plant design is considered, a long-term decrease in the geostorage pressure is found. Correspondingly, the charging power always meets the specifications, while the discharging power decreases slowly from the 20th storage cycle onwards to 79 MW in the 31st cycle. The newly developed simulation tool thus allows one to predict achievable power rates and geostorage pressures for PM-CAES systems, enabling the identification of efficient PM-CAES designs.

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    • Witte, Francesco
    • Tuschy, Ilja

  • Profilbereich

    • Erneuerbare Energien und nachhaltige Entwicklung

  • Forschungsfeld

    • Wärme
    • Netzintegration

  • Fachbereich

    • Fachbereich 2: Energy and Life Science

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  • 2021
  • Journal Article
  • • Wolf Pfeiffer
    • Francesco Witte
    • Ilja Tuschy
    • Sebastian Bauer
  • • PM-CAES
    • Compressed air energy storage
    • Geological storage
    • Coupled simulations

• Grid Support with Wind Turbines: The Case of the 2019 Blackout in Flensburg

  Gloe, A. ., Jauch, C. ., & Räther, T. . (2021). Grid Support with Wind Turbines: The Case of the 2019 Blackout in Flensburg. Energies, 14(6), 1697. http://doi.org/10.3390/en14061697

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  The work presented in this paper aims to show how modern wind turbines can help to control the frequency in a small grid which suffers from large power imbalances. It is shown for an exemplary situation, which occurred in Flensburg’s distribution grid in 2019: a major blackout, which occurred after almost two hours in islanding operation, affecting almost the entire distribution grid, which supplies approximately 55,000 households and businesses. For the analysis, a wind turbine model and a grid support controller developed at the Wind Energy Technology Institute are combined with real measurements from the day of the blackout to generate a fictional yet realistic case study for such an islanding situation. For this case study, it is assumed that wind turbines with grid support functionalities are connected to the medium voltage distribution grid of the city. It is shown to what extent wind turbines can help to operate the grid by providing grid frequency support in two ways: By supplying synthetic inertia only, where the wind turbines can help to limit the rate of change of frequency in the islanded grid directly after losing the connection to the central European grid. In combination with the primary frequency control capabilities of the wind turbines (WTs), the disconnection of one gen set in the local power station might have been avoided. Furthermore, wind turbines with primary frequency control capabilities could have restored the grid frequency to 50 Hz shortly after the islanding situation even if the aforementioned gen-set was lost. This would have allowed connecting a backup medium voltage line to the central European grid and thereby avoiding the blackout.

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  • Personenseiten

    • Gloe, Arne
    • Jauch, Clemens

  • Forschungsprojekt

    • Grenzland INNOVATIV Schleswig-Holstein

  • Abteilung/Einrichtung

    • Wind Energy Technology Institute

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  • 2021
  • Journal Article
  • • Arne Gloe
    • Prof. Dr. Clemens Jauch
    • Thomas Räther
  • • WETI

• Adapting Behavior Driven Development (BDD) for large-scale software systems

  Irshad, M. ., Britto, R. ., & Petersen, K. . (2021). Adapting Behavior Driven Development (BDD) for large-scale software systems. Journal of Systems and Software, 177, 110944.

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    • Petersen, Kai

  • Abteilung/Einrichtung

    • FLAIR - Flensburg Artificial Intelligence Research

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  • 2021
  • Journal Article
  • • Mohsin Irshad
    • Ricardo Britto
    • Kai Petersen