Centre for Marine and Renewable Energy (MaREI) - Conference Items

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    EV specific time-of-use rates analysis for workplace charging
    (Institute of Electrical and Electronics Engineers (IEEE), 2021-08-02) Kucuksari, Sadik; Erdogan, Nuh; Sustainable Energy Authority of Ireland
    EV specific time-of-use rate plans have been recently introduced by several utilities to overcome the demand charge issue that is the main barrier impeding EV growth in the commercial and industrial sector. This study analyses two EV specific TOU rates in place from a customer and the grid perspectives. The analysis relies on a developed optimal cost model with coordinated charging strategies that minimizes the total cost of a workplace charging station over its lifetime. From a customer perspective, it is shown that the cost benefits are not always achievable and depends on the rates provided. From the grid perspective, the peak demand is found to be increased. Thus, the EV specific rates may not always provide an efficient use of the grid assets.
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    Looking for a simplified approach for the propagation of systematic uncertainty in the motion response of a floater
    (IOP Publishing, 2022-11) Gueydon, S.; Lyden, Eoin; Judge, Frances M.; O'Shea, Michael; Murphy, Jimmy; Horizon 2020
    This new research considers the 3 main motions of the moored floater (surge, heave and pitch) in head waves and it explores ways to estimate the systematic uncertainties on the RAOs, and 2 other metrics for these signals. Based on linear hydrostatics and the linear potential flow theory, simple relations can be found that bind the main characteristics of a floater. These relations are transformed using linear algebra to express how uncertainty bias on the main characteristics of the tested system can be propagated to the motion responses of the floater. Thanks to this approach, variations of the mooring stiffness, position of the centre of mass, radia of gyration can be represented through simple formulations that allow to very effectively assess their impact of the motion RAOs and other metrics. This approach is verified by comparing simulation and test results of the semisubmersible of the MARINET2 floating wind round robin campaign to approximations deduced from these theoretical relations.
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    Combined current and wind simulation for floating offshore wind turbines
    (IOP Publishing, 2022) Otter, Aldert; Desmond, C.; Flannery, Brian; Murphy, Jimmy; Science Foundation Ireland
    This paper describes the validation of a novel method to simulate current loading on a floating offshore wind turbine model. A dynamic winch actuator is used to emulate the drag force of current on the platform of the model with a Software in the Loop application. Current loads are combined with wave- and wind loads. The results of experiments with physical current are validated against the results of experiments with simulated current. A method to simulate wave-current interactions is also described. The results show that the winch actuator can reliably emulate current induced drag forces in comparison with physical current under various combinations of environmental loads. Experimental repeatability of the response of the platform is shown to be superior when using simulated- rather than physical current.
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    Structure design and assessment of a floating foundation for offshore wind turbines
    (American Society of Mechanical Engineers (ASME), 2019-11-03) Ye, Q.; Cheng, S.; Kim, B.; Collins, K.; Iglesias, Gregorio
    This paper summarizes the assessment of the structural analysis and design of a floating foundation for offshore floating wind turbine (FWT) based on DNVGL standard and Eurocode in terms of economy and reliability. The wind loads are calculated using empirical equations. The wave loads are obtained and verified using various methods including hand calculation, AQWA and Flow-3D. It is found that the shell thickness could be reduced significantly by introducing the stiffeners (stringer or ring), which can decrease the weight of the hull and lower the cost. While DNVGL and Eurocode yield similar design solutions if using plane shell structures, Eurocode significantly underestimates the buckling resistance of stiffened cylindrical shells.
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    Comparative realistic objectives oriented optimization framework for EV charging scheduling in a distribution system
    (Institute of Electrical and Electronics Engineers (IEEE), 2022-05-18) Güldorum, Hilmi Cihan; Erenoğlu, Ayşe Kübra; Erdinç, Ozan; Şengör, İbrahim; Türkiye Bilimsel ve Teknolojik Araştirma Kurumu; Türkiye Bilimler Akademisi
    The integration of large-scale electric vehicles (EVs) into the distribution system has emerged as a critical topic of research with the proliferation of EVs over the years. To mitigate the negative effects of EVs on the distribution system (DS), in this study, the optimal operation of an EVPL is investigated with a model in the form of mixed-integer quadratic constrained programming (MIQCP) that aims to minimize a variety of realistic objectives including active power losses, charging cost or voltage deviations while taking DS constraints into account. Also, uncertain behavior of the EVPL has been considered via machine-learning based forecasting by using historic data. The effectiveness of the proposed model has been evaluated using a 33-bus test system with 15-minute time granularity and compared to models that had various objective functions.