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oai:digital.library.adelaide.edu.au:2440/1396162026-06-14T23:47:54Zcom_2440_14759col_2440_14760

Ertugrul, Nesimi Ding, Boyin Gao, Qiang School of Electrical and Mechanical Engineering 2023 https://hdl.handle.net/2440/139616 Offshore wind and wave energy represent vast untapped resources in the ocean, holding significant potential for making long-term contributions to future energy supplies and facilitating the ongoing energy transition. The integration of these ocean renewables has emerged as a compelling concept, garnering increasing interest from research, industry and government sectors, primarily due to its potential benefits, such as enhanced energy production, reduced energy costs and energy variability. However, the successful implementation of offshore wind, wave and combined energy systems requires addressing various challenges, including complex system dynamics, optimal justifications (such as technology and location selection), grid integration and energy reliability and dispatchability. Although the concept of integrating offshore wind and wave energy systems has been proposed and studied over the past decade, there have several gaps that have not been thoroughly investigated. Currently, offshore wind and wave sources are studied separately, lacking a thorough analysis of combined energy systems, particularly on Australian coasts. As a result, there is a need for systematic studies on the combined farms by considering various factors. In addition, traditional economic metrics have limitations and fail to capture energy benefits and power regulation impacts. Integrating WECs with WTs requires power smoothing mechanisms, but their impact on the combined system performance and optimal sizing are lacking in the literature. Moreover, understanding the power intermittence and energy variability characteristics of offshore wind and wave is crucial for combined system design in terms of mechanical stress, control strategies, generator sizing and power regulation. To enhance the firmness of the ocean energy supply, further research is also needed to investigate the feasibility, optimal selection and comparison of energy storage systems under different offshore farm configurations. Therefore, addressing these gaps is vital for informed decision-making and successful offshore energy development. Firstly, this research develops a multi-factor method for evaluating and selecting optimal locations for hybrid development by conducting a comprehensive assessment of offshore wind and wave energy along the Australian coastline. The thesis also investigates the spatial variation of technical feasibility and economic potential of different offshore energy farm configurations by utilizing innovative evaluation matrices developed in this research. Furthermore, this thesis examines the impact of energy storage systems on WECs performance and addresses gaps in the optimal sizing of WEC generators. In addition, a new method is developed for capturing the short-term power intermittence and a novel concept of ”virtual energy storage” is proposed to explore the long-term energy variability of the combined system, to quantify the energy smoothing benefits in both technical and economic aspects. Lastly, this thesis proposes an effective approach to determining the technical parameters of ESS for offshore energy systems, considering various options and their applicability. Overall, the findings of this thesis highlight the advantages of combined wind and wave energy farms and their competitiveness in terms of lifecycle costs and technical feasibility and provide analytical tools to address the critical challenges of developing combined energy farms in the future. These contributions advance knowledge and provide valuable insights and practical recommendations to advance the successful deployment and integration of offshore wind and wave energy systems. Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Mechanical Engineering, 2023 en Offshore wind energy Wave energy Combined wind and wave Techno-economic analysis Energy variability Energy storage Resources, Economics and Technology Feasibility of Hybrid Offshore Energy Farm Thesis This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals.open.access