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This work aimed to test the feasibility, both experimentally and numerically, of a novel concept for a robust Wave Energy Converter (WEC) operating in the near-shore region. The converter uses a series of non-return valves, constrained by a tapered pipe, where the incoming wave builds up pressure in each compartment and finally drives a turbine onshore with the pressurised water. The device is aimed at remote communities, to gain energy security and reduce dependence on imports. The device facilitates local engagement, and it is intended that local people are trained to perform most maintenance tasks using low cost, readily available, parts. This work assessed the feasibility of the WEC through physical testing, the results of which were compared to initial numerical models. The device was shown to capture energy and, through a case study of Ushant Island off the coast of France, was shown to have the potential to become part of the future energy mix for remote communities. [ABSTRACT FROM AUTHOR]

The continuous advancement within the offshore wind energy industry is propelled by the imperatives of renewable energy generation, climate change policies, and the zero-emission targets established by governments and communities. Increasing the dimensions of offshore wind turbines to augment energy production, enhancing the power generation efficiency of existing systems, mitigating the environmental impacts of these installations, venturing into deeper waters for turbine deployment in regions with optimal wind conditions, and the drive to develop floating offshore turbines stand out as significant challenges in the domains of development, installation, operation, and maintenance of these systems. This work specifically centers on providing a comprehensive review of the research undertaken to tackle several of these challenges using machine learning and artificial intelligence. These machine learning-based techniques have been effectively applied to structural health monitoring and maintenance, facilitating the more accurate identification of potential failures and enabling the implementation of precision maintenance strategies. Furthermore, machine learning has played a pivotal role in optimizing wind farm layouts, improving power production forecasting, and mitigating wake effects, thereby leading to heightened energy generation efficiency. Additionally, the integration of machine learning-driven control systems has showcased considerable potential for enhancing the operational strategies of offshore wind farms, thereby augmenting their overall performance and energy output. Climatic data prediction and environmental studies have also benefited from the predictive capabilities of machine learning, resulting in the optimization of power generation and the comprehensive assessment of environmental impacts. The scope of this review primarily includes published articles spanning from 2005 to March 2023. [ABSTRACT FROM AUTHOR]

The continuous advancement within the offshore wind energy industry is propelled by the imperatives of renewable energy generation, climate change policies, and the zero-emission targets established by governments and communities. Increasing the dimensions of offshore wind turbines to augment energy production, enhancing the power generation efficiency of existing systems, mitigating the environmental impacts of these installations, venturing into deeper waters for turbine deployment in regions with optimal wind conditions, and the drive to develop floating offshore turbines stand out as significant challenges in the domains of development, installation, operation, and maintenance of these systems. This work specifically centers on providing a comprehensive review of the research undertaken to tackle several of these challenges using machine learning and artificial intelligence. These machine learning-based techniques have been effectively applied to structural health monitoring and maintenance, facilitating the more accurate identification of potential failures and enabling the implementation of precision maintenance strategies. Furthermore, machine learning has played a pivotal role in optimizing wind farm layouts, improving power production forecasting, and mitigating wake effects, thereby leading to heightened energy generation efficiency. Additionally, the integration of machine learning-driven control systems has showcased considerable potential for enhancing the operational strategies of offshore wind farms, thereby augmenting their overall performance and energy output. Climatic data prediction and environmental studies have also benefited from the predictive capabilities of machine learning, resulting in the optimization of power generation and the comprehensive assessment of environmental impacts. The scope of this review primarily includes published articles spanning from 2005 to March 2023.

The northern Gulf of Mexico (nGoM) is a globally important region for oil extraction and supports a diverse assemblage of marine birds. Due to their frequent contact with surface waters, diverse foraging strategies, and the ease with which oil adheres to feathers, seabirds are particularly susceptible to hydrocarbon contamination. Given the chronic and acute exposure of seabirds to oiling and a lack of studies that focus on the exposure of seabirds to oiling in sub-tropical and tropical regions, a greater understanding of the vulnerability of seabirds to oil in the nGoM appears warranted. We present an oil vulnerability index for seabirds in the nGoM tailored to the current state of knowledge using new, spatiotemporally expensive vessel-based seabird observations. We use information on the exposure and sensitivity of seabirds to oil to rank seabird vulnerability. Exposure variables characterized the potential to encounter oil and gas (O&G). Sensitivity variables characterized the potential impact of seabirds interacting with O&G and are related to life history and productivity. We also incorporated uncertainty in each variable, identifying data gaps. We found that the percent of seabirds’ habitat defined as highly suitable within 10 km of an O&G platform ranged from 0%-65% among 24 species. Though O&G platforms only overlap with 15% of highly suitable seabird habitat, overlap occurs in areas of moderate to high vulnerability of seabirds, particularly along the shelf-slope. Productivity-associated sensitivity variables were primarily responsible for creating the gradient in vulnerability scores and had greater uncertainty than exposure variables. Highly vulnerable species (e.g., Northern gannet (Morus bassanus)) tended to have high exposure to the water surface via foraging behaviors (e.g., plunge-diving), older age at first breeding, and an extended incubating and fledging period compared to less vulnerable species (e.g., Pomarine jaeger (Stercorarius pomarinus)). Uncertainty related to productivity could be reduced through at-colony monitoring. Strategic seabird satellite tagging could help target monitoring efforts to colonies known to use the nGoM, and continued vessel-based observations could improve habitat characterization. As offshore energy development in the nGoM continues, managers and researchers could use these vulnerability ranks to identify information gaps to prioritize research and focal species.

Despite the EU's ambitious goals regarding the expansion of marine renewables as a promising climate mitigation and energy security measure, the majority of hydrocarbon exploitation continues occurring offshore with more than 500 oil and gas installations operating in European seas. Given the grave environmental risks these activities pose, the EU has developed secondary rules with implications for the regulation of offshore energy generation. These normative developments have added an extra layer of regional, supra-national regulation of ocean energy production across European seas, which necessarily interacts with the simultaneously applicable rules under regional sea agreements. The article examines the implications of the normative interplay between EU law and regional sea agreements in terms of shaping the environmental regulation of offshore energy production across Europe. In that respect, it explores whether EU law instruments and the EU's sophisticated institutional framework can enhance the rules and standards under the regional sea agreements, in terms both of adding normative content to them and supporting their enforcement. In light of the mutual cross-fertilization between the two applicable regimes, the article equally looks into the normative impact of regional sea conventions on the EU legal framework and its implementation in the context of offshore energy production. [ABSTRACT FROM AUTHOR]

Initially, international investment law and international law on the protection of the marine environment were two branches that developed separately. As these international regimes mature, they often speak to the same facts, bringing about their ever-increasing normative interaction, way before any disputes arise. The regulation of investments in offshore energy production is chosen as a case study because it exemplifies how these two bodies of international law can interact. The article does not conceptualize these two international regimes as inherently antagonistic but instead highlights their potential complementarity. Yet, it is primarily the issue of normative conflicts between those two regimes which has generated heated scholarly debates. Against the backdrop of sweeping critiques about the potential 'regulatory chill' of international investment agreements and their investor-State dispute settlement mechanism, this contribution examines whether arbitral tribunals have interpreted and applied investment rules in a fashion that can unduly restrict the discretion of host States to honour their marine environmental obligations. First, it explores why and how international investment law and marine environmental law interact and influence each other's implementation. In a second step, the article investigates the impact (if any) of investment obligations on the discretion of host States to comply with their marine environmental protection obligations. Adopting a forward-looking perspective, it finally enquires into the potential impact of the reformed provisions under new generation IIAs on the right and duty of States to take all necessary measures to protect the marine environment against pollution from offshore energy production activities. [ABSTRACT FROM AUTHOR]

Compactness and weight minimization are key aspects for successful and widespread implementation of waste heat recovery steam cycles in off-shore oil and gas platforms due to the site weight and volume footprint constraints. The power plant off-shore must be designed for flexibility in its operations to provide varying power demands across multiple time scales. Reliability of the heat and power production units is crucial. Within a case study in an off-shore platform in the Norwegian Continental Shelf, this article conducts design optimization of compact and low-weight steam cycles for power production from gas turbine exhaust and transient analysis of the core of heat recovery steam generators (HRSGs) via dynamic modeling and simulation, considering once-through steam generators (OTSGs) for the HRSGs. A method for simultaneous thermodynamic and heat exchanger geometry optimization design for bottoming cycles is applied, with the main objective being weight minimization and compactness of the cycle heat exchangers. Ten different optimal minimum weight bottoming cycle designs are provided by selecting ten different manufacturable tubes. The resulting bottoming cycle designs are compared in terms of weight, OTSG core weight distribution, heat transfer area, and footprint. The resulting bottoming cycle weight varies from 48.4 to ca. 87.10 ton for designs sensible for off-shore applications, and from 95.8 to 178.9 ton when selecting outer tube diameters typical of onshore applications. Smaller outer tube diameter selection in OTSG bundles is a key driver for low-weight and compact steam cycle designs. Three different designs representing light, normal, and heavy OTSG designs are compared by dynamic trajectory and response time analysis under transient scenarios by means of dynamic modeling and simulation. More compact and lighter designs respond faster to changes in the gas turbine (GT) operation upstream the OTSG. The results in this analysis indicate the need for feedforward control. Feedback control alone is probably not a good option due to the high OTSG open loop stabilization time and large sensitivity to GT exhaust gas variations. More compact and low-weight designs based on the OTSG can reduce potential challenges in controlling and stabilizing bottoming cycles for power production.

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Offshore photovoltaic energy is possibly the most important future step in the harnessing of solar energy. Since no long-term offshore photovoltaic installation exists to date, various unknowns are still present, creating a research gap. For instance, floating structures will have some type of response to incoming waves. This response is highly dependent on the design of the floating structure. This response will have some effect on the insolation on offshore photovoltaic systems installed on floating structures. This research presents a simulation tool that would allow an offshore system designer to assess this effect in order to minimize it and thus, optimize the energy yield of the system. Furthermore, this simulation tool was verified with an experimental setup simulating sinusoidal wave responses and the results are presented in this research. Finally, a parametric analysis was performed taking days close to the 21st of each month of the year for photovoltaic installations facing south with fixed inclinations of 30 ° and 5 ° This research will improve the design of offshore floating platforms used for photovoltaic installations.

Advances in renewable energy recourses technologies have paved the way for increased utilization of DC grids in modern power systems. In particular, high voltage DC (HVDC) transmission cables are used to harvest offshore energy. Since failure diagnosis and repair of the buried offshore cables under the sea bed involve quite laborious tasks, accurate fault location is of vital importance. This paper proposes a novel fault location method based on the synchronized measurement of conductors and sheaths currents in each terminal without requiring the voltage signal. Unlike the traveling-wave-based methods, the proposed method is developed for multi-terminal HVDC systems without requiring any high precision measurement infrastructure. The proposed method can be implemented for different system topologies as well as fault resistance and fault distance. The fault location method can provide accurate results even if 10 ms time window samples are imported into the proposed algorithm. In addition, accuracy of the fault location using the proposed method is not affected significantly by noisy condition. Different test systems have been simulated to evaluate performance of the proposed method in various scenarios. Obtained results confirm that the proposed practical method can provide the accurate fault location for all different scenarios and conditions. [ABSTRACT FROM AUTHOR]

This paper revisits research undertaken by the Authors with Professor J B Burland in which key contributions were made to the pioneering Magnus Foundation Monitoring Project (FMP), Hutton Tension Leg Platform (TLP) and Gullfaks-C platform oil production platform projects in the North Sea. Close liaison with industry and an integrated approach that combined high quality laboratory and in-situ testing with cutting-edge numerical analysis and accurate observations of full-scale field behaviour were central to the improvements achieved in analysing the foundations of these and similar structures. The paper asserts the central importance of understanding regional geology before reviewing how teams led by John Burland developed new laboratory and field monitoring instruments, as well as experimental and numerical approaches that have had a lasting impact in many areas of geotechnical engineering. Recent developments that sprang from the projects and the associated research programmes are highlighted. Particular attention is given to subsequent improvements to pile design methods whose development started with the first two cited case histories, as these and later developments are now contributing to a worldwide shift towards renewable, low-carbon, wind-energy production. [ABSTRACT FROM AUTHOR]

Wind and wave energy are the main forms of offshore energy. In this study, a new joint wind and wave energy (JWWE) power conversion system, which simultaneously features wind power generation and wave power generation, is investigated. In the JWWE power generation system, a dual‐stator linear and rotary permanent magnet generator (DSLRPMG) is employed to directly convert the wind and wave energy. The topology and operating principles of the power generation system are analysed, and the rectifier topology with two three‐phase bridge converter is introduced for the JWWE power generation system. On the basis of the vector control method, the mathematical model of the DSLRPMG is deduced. The virtual flux direct power control method without any AC voltage sensors is applied for the power generation system. A new decoupling control method including flux decoupling and power decoupling is proposed and analysed. Meanwhile, an experimental setup is constructed, and the experiments are done. Both the simulation and experimental results show the validity and correctness of the control strategy. [ABSTRACT FROM AUTHOR]

Connectivity of marine populations and ecosystems is crucial to maintaining and enhancing their structure, distribution, persistence, resilience and productivity. Artificial hard substrate, such as that associated with oil and gas platforms, provides settlement opportunities for species adapted to hard substrates in areas of soft sediment. The contribution of artificial hard substrate and the consequences of its removal (e.g. through decommissioning) to marine connectivity is not clear, yet such information is vital to inform marine spatial planning and future policy decisions on the use and protection of marine resources.This study demonstrates the application of a social network analysis approach to quantify and describe the ecological connectivity, informed by particle tracking model outputs, of hard substrate marine communities in the North Sea. Through comparison of networks with and without artificial hard substrate, and based on hypothetical decommissioning scenarios, this study provides insight into the contribution of artificial hard substrate, and the consequence of decommissioning, to the structure and function of marine community connectivity.This study highlights that artificial hard substrate, despite providing only a small proportion of the total area of hard substrate, increases the geographic extent and connectivity of the hard substrate network, bridging gaps, thereby providing 'stepping stones' between otherwise disconnected areas of natural hard substrate. Compared to the baseline scenario, a decommissioning scenario with full removal of oil and gas platforms results in a nearly 60% reduction in connectivity. Such reduction in connectivity may have negative implications for species' distribution, gene flow and resilience following disturbance or exploitation of marine hard substrate communities.Synthesis and applications. Social network analysis can provide valuable insight into connectivity between marine communities and enable the evaluation of impacts associated with changes to the marine environment. Providing standardized, transparent and robust outputs, such a tool is useful to facilitate understanding across different disciplines, including marine science, marine spatial planning and marine policy. Social network analysis therefore has great potential to address current knowledge gaps with respect to marine connectivity and crucially facilitate assessment of the impacts of changes in offshore substrate as part of the marine spatial planning process, thereby informing policy and marine management decisions. [ABSTRACT FROM AUTHOR]

Knowledge about the impact of anthropogenic disturbances on the behavioural responses of cetaceans is constrained by lack of data on fine-scale movements of individuals. We equipped five free-ranging harbour porpoises (Phocoena phocoena) with high-resolution location and dive loggers and exposed them to a single 10 inch3 underwater airgun producing high-intensity noise pulses (2–3 s intervals) for 1 min. All five porpoises responded to capture and tagging with longer, faster and more directed movements as well as with shorter, shallower, less wiggly dives immediately after release, with natural behaviour resumed in less than or equal to 24 h. When we exposed porpoises to airgun pulses at ranges of 420–690 m with noise level estimates of 135–147 dB re 1 µPa2s (sound exposure level), one individual displayed rapid and directed movements away from the exposure site and two individuals used shorter and shallower dives compared to natural behaviour immediately after exposure. Noise-induced movement typically lasted for less than or equal to 8 h with an additional 24 h recovery period until natural behaviour was resumed. The remaining individuals did not show any quantifiable responses to the noise exposure. Changes in natural behaviour following anthropogenic disturbances may reduce feeding opportunities, and evaluating potential population-level consequences should be a priority research area.

The new Act of the Electrical sector sets up a complex regulating framework that covers above all the tariff system of premiums by the renewable power producers. The drastic measures enacted by the executive in crisis times try to stop the financial imbalances of a sector that expanded protected by public incentives. But changes threat the viability of an industry that had became leader in the Spanish economy and at the same time they create conflicts related to basic principles of our legal order as competence, free competition, non retroactivity of the unfavourable norms, legal certainty, public interest, etc. From amongst the several renewable power sources that exist, in this work we focus on the regime of «offshore energy» or «ocean energy» checking how normative changes do affect it. In spite of being on a pre-commercial stage of technological development, offshore energy is a renewable source with great prediction that has a positive enviromental impact which has made to place hopes in it so as to assure the power supply in the future in a sustainable way. In this work we note that the need to provide renewable oceanic sources with an independent regulation with the aim of foreseeing their development over the course of next decades and as a way to rise the political and social commitment with enviroment.

Abstract Maritime industries routinely collect critical environmental data needed for sustainable management of marine ecosystems, supporting both the blue economy and future growth. Collating this information would provide a valuable resource for all stakeholders. For the North Sea, the oil and gas industry has been a dominant presence for over 50 years that has contributed to a wealth of knowledge about the environment. As the industry begins to decommission its offshore structures, this information will be critical for avoiding duplication of effort in data collection and ensuring best environmental management of offshore activities. This paper summarises the outcomes of a Blue Growth Data Challenge Workshop held in 2017 with participants from: the oil and gas industry; the key UK regulatory and management bodies for oil and gas decommissioning; open access data facilitators; and academic and research institutes. Here, environmental data collection and archiving by oil and gas operators in the North Sea are described, alongside how this compares to other offshore industries; what the barriers and opportunities surrounding environmental data sharing are; and how wider data sharing from offshore industries could be achieved. Five primary barriers to data sharing were identified: 1) Incentives, 2) Risk Perception, 3) Working Cultures, 4) Financial Models, and 5) Data Ownership. Active and transparent communication and collaboration between stakeholders including industry, regulatory bodies, data portals and academic institutions will be key to unlocking the data that will be critical to informing responsible decommissioning decisions for offshore oil and gas structures in the North Sea. Highlights • The oil and gas industry has a 50 year archive of environmental data. • There have been successful collaborations to make these data widely available. • A standardised approach is now needed to facilitate environmental data sharing. [ABSTRACT FROM AUTHOR]

With the need to integrate renewable energy sources into the current energy portfolio and the proximity of power consumers to ocean coastlines, it is important to evaluate marine energy systems, specifically wave energy converters (WECs), as potential solutions for meeting electricity needs. The ability to model these systems computationally is vital to their eventual deployment. The power development, economics, grid integration requirements, operations and maintenance requirements, and ecological impacts must be understood before these devices are physically installed. However, the research area of WEC array optimization is young, and the few available results of previously implemented optimization methods are preliminary. The purpose of this work is to introduce a new WEC array optimization framework to explore systems-level concerns, specifically WEC layout and device spacing. A genetic algorithm approach that utilizes an analytical hydrodynamic model and includes an array cost model is presented, and the resulting optimal layouts for a preliminary test case are discussed. This initial work is integral in providing an understanding of device layout and spacing and is a foundational starting point for subsequent and more advanced WEC array optimization research. [ABSTRACT FROM AUTHOR]

This paper presents a review of the main electrical components that are expected to be present in marine renewable energy arrays. The review is put in context by appraising the current needs of the industry and identifying the key components required in both device and array-scale developments. For each component, electrical, mechanical and cost considerations are discussed; with quantitative data collected during the review made freely available for use by the community via an open access online repository. This data collection updates previous research and addresses gaps specific to emerging offshore technologies, such as marine and floating wind, and provides a comprehensive resource for the techno-economic assessment of offshore energy arrays. [ABSTRACT FROM AUTHOR]

At autonomous electricity grids Renewable Energy (RE) contributes significantly to energy production. Offshore resources benefit from higher energy density, smaller visual impacts, and higher availability levels. Offshore locations at the West of Crete obtain wind availability ≈80%, combining this with the installation potential for large scale modern wind turbines (rated power) then expected annual benefits are immense. Temporal variability of production is a limiting factor for wider adaptation of large offshore farms. To this end multi-generation with wave energy can alleviate issues of non-generation for wind. Spatio-temporal correlation of wind and wave energy production exhibit that wind and wave hybrid stations can contribute significant amounts of clean energy, while at the same time reducing spatial constrains and public acceptance issues. Offshore technologies can be combined as co-located or not, altering contribution profiles of wave energy to non-operating wind turbine production. In this study a co-located option contributes up to 626 h per annum, while a non co-located solution is found to complement over 4000 h of a non-operative wind turbine. Findings indicate the opportunities associated not only in terms of capital expenditure reduction, but also in the ever important issue of renewable variability and grid stability.

For developing a large-scale combined system with a number of distributed resources, an appropriate compensation strategy based on the system components and changeable condition must be configured to handle the characteristics of the internal systems. Since renewable sources generate various fluctuations, the compensation plans for the storage device connected along with the sources should be supported by a precise expectation method. A cooperative strategy involving the sharing of the DC section with environmentally sensitive generators, like photovoltaic system (PVs) or waves, demands appropriate ESS compensation solutions, owing to its complexity. An active power-control algorithm with voltage-expectation based on the DC power flow is introduced in this paper and is applied in the designed case studies performed on the electromagnetic transient simulation. DC based multi-generation system is composed by applying tidal generator and super capacitor. To utilize wind energy, an offshore wind-wave generation system was utilized in the verification process. [ABSTRACT FROM AUTHOR]

This paper presents a review of the main electrical components that are expected to be present in marine renewable energy arrays. The review is put in context by appraising the current needs of the industry and identifying the key components required in both device and array-scale developments. For each component, electrical, mechanical and cost considerations are discussed; with quantitative data collected during the review made freely available for use by the community via an open access online repository. This data collection updates previous research and addresses gaps specific to emerging offshore technologies, such as marine and floating wind, and provides a comprehensive resource for the techno-economic assessment of offshore energy arrays.

In the energy system, the renewable energy sources (RES) play an increasingly important place, contributing to a sustainable and efficient development, compatible with a cleaner environment. Among these energy sources, the marine RES, and especially the offshore energy increased from one year to another. The paper contains a desk analysis of the offshore energy area, showing figures, images, dates and conclusions on these new technologies and their effects on short and long terms. Also, a SWOT analysis is included, representing a necessary assessment of the strong and weak points, trying to adjust the strengths to the opportunities and reduction at a minimum level of the threats, eliminated the weak points. The projects based on this type of energy source, their positive results outline a promising perspective for the investors and authorities. The benefits are conclusive in this area: this inexhaustible and free resource generates energy with zero emissions, provides permanent and temporary jobs, services and economic growth, a balanced proportion between supply and demand of energy. [ABSTRACT FROM AUTHOR]

This paper explores the social dimensions of an experimental release of carbon dioxide (CO 2 ) carried out in Ardmucknish Bay, Argyll, United Kingdom. The experiment, which aimed to understand detectability and potential effects on the marine environment should there be any leakage from a CO 2 storage site, provided a rare opportunity to study the social aspects of a carbon dioxide capture and storage-related event taking place in a lived-in environment. Qualitative research was carried out in the form of observation at public information events about the release, in-depth interviews with key project staff and local stakeholders/community members, and a review of online media coverage of the experiment. Focusing mainly on the observation and interview data, we discuss three key findings: the role of experience and analogues in learning about unfamiliar concepts like CO 2 storage; the challenge of addressing questions of uncertainty in public engagement; and the issue of when to commence engagement and how to frame the discussion. We conclude that whilst there are clearly slippages between a small-scale experiment and full-scale CCS, the social research carried out for this project demonstrates that issues of public and stakeholder perception are as relevant for offshore CO 2 storage as they are for onshore. [ABSTRACT FROM AUTHOR]