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Until the middle of 20th century, there was a strong conviction that the next century would be the age of renewable and nuclear energy resources. However, at present, the whole world is dependent on fossil fuels to satisfy their energy need. Environmental pollution and global warming are the main issues associated with the use of fossil fuels for electricity generation. As per the report of US Energy Information IE Outlook 2016, coal, natural gas, and petroleum share nearly 67.2% of global electricity generation whereas renewable energy shares only 21.9%. This share is only one-fifth of the global electricity demand. According to the IEA 2016 Medium Term Renewable Energy Market Report, worldwide power production capacity of marine was only 539 MW in 2014, and to reach at a level of 640 MW, it will take 2021. The oceans cover about 70% of the Earth and acts as the largest thermal energy collector. A recent study reveals that global development capability of ocean energy is approximated to be 337 GW, and more than 885 TWH of electricity can be produced from this potential.

Off-grid hybrid power generation systems are widely used in various applications. In particular, RES-based stand-alone power systems can be used to supply offshore load demands, river lighthouses, and other remote applications. The use of RESs has many environmental and economic benefits over other energy sources, especially for the reduction of marine pollution . Solar and wind energies are the most applicable RESs, which are extremely abundant and available at sea. They mainly depend on solar irradiation and wind speed. Therefore, they have many challenges since they are intermittent and unpredictable. In addition, the onboard utilization of PV panels and WT have been investigated from various technical, economic, and management aspects to obtain the maximum power on the limited space ofthe ship.

Marine energy devices harness power from attributes of ocean water to form a sustainable energy source. Knowledge gaps remain about whether marine energy systems can affect the environment, adding another threat to animal populations and habitats already under pressure from climate change and anthropogenic activities. To date, potential environmental effects have been studied under the scope of stressor–receptor interactions, where moving parts of, or emissions from, a system could harm the animals, habitats, and natural processes. While crucial for understanding effects and identifying knowledge gaps, this approach misses a holistic view of what animals may experience in the presence of marine energy systems. We look at six biological consequences and forces that drive the health of an animal population and the effects expected from marine energy development: success of early life stages; changes in competitive capabilities; growth and survival based on food availability; susceptibility to predators; injury or death; and reproductive success. We use case studies to develop this approach, focusing on a variety of marine animals. An approximate level of risk is assigned for each interaction based on the biological consequences. This work highlights the need to examine the effects of marine energy development on animal populations within their natural habitats.

As traditional energy sources are increasingly depleting, ocean energy has become an emergent potential clean energy source. Wave energy, as an important part of ocean-derived energy, has been studied and utilized by coastal countries worldwide, which have developed various wave energy converters. In this paper, a new wave energy converter is designed, and water movement in fluid channels is analyzed. The results are, then, used to generate a mathematical model that simulates water movement. Based on this approach, the water movement state is analyzed, and a formula for calculating the natural frequency of water movement in the power generator is derived. The formula shows that the characteristic length of the water movement in the proposed generator and the backboard tilt angle at the exit point of the fluid channel are two design-related variables that can be used to alter the natural frequency, a regular wave experiment is conducted based on the fluid model, which is designed based on the natural frequency formula, to verify the changes in model torque and speed as well as whether the model can operate under normal wave conditions. This study lays a theoretical foundation for the design of further experiments and engineering prototypes to verify the validity of mathematical models by way of experimental analysis.

Tidal power lagoons have the potential to provide a reliable and long-term source of renewable power. The implementation of tidal lagoons will impact the tidal conditions and hydrodynamics of the surrounding coastal system. Impact assessments in the academic literature have generally investigated working proposals from industry of various shapes and sizes. As such, differences between the impacts arising from considered power plants in varying sites are in part influenced by the individual scheme characteristics, potentially masking the influence of site-specific factors. In this study, scheme design consistency is maintained, providing a basis to focus solely on the merits of the selected locations with regards to any associated impacts. The simulated tidal power lagoons are located in the Bristol Channel and Irish Sea, two distinct but tidally connected regions on the British coastline with contrasting marine environment characteristics. Results indicate that the more constrained geometry of the Bristol Channel contributes to higher individual and cumulative impacts than potential developments in the Irish Sea. This is in part facilitated by the higher degree of blockage introduced by tidal lagoon developments in the Bristol Channel. Furthermore, far-field impacts are found to be less pronounced compared to predictions reported in tidal barrage modelling studies.

Ocean energy is a kind of renewable energy contained in seawater, which has the characteristics of large total reserves, sustainable use, and its being green and clean. Influenced by rising oil prices and global climate change, an increasing number of countries are attaching great importance to the strategic position of ocean energy in the future energy sector, and are formulating national ocean energy development roadmaps and conducting research and development on ocean energy technologies. Ocean current energy is a widely existing kind of ocean energy with abundant reserves. However, due to the low current velocity in most of the deep sea, low current energy has not been effectively exploited. In this paper, the Blade element momentum (BEM) theory based on Vortex column theory is used to design a special airfoil for low current energy applications, and a prototype turbine with rotor diameter of 4.46 m and tip speed ratio (TSR) of 6 is fabricated. In order to achieve stable electric power output, this paper designs a hydraulic conversion power generation control system with flexible control, and the hydraulic system working pressure designed to 21 MPa. In this paper, we conducted towing experiments on the prototype of an ocean current energy turbine, with hydraulic transmission and a control power generation system applied to the low flow rate, and achieved the target of hydraulic motor speed in the range of 14.7~15.9 r/min and steady-state speed accuracy in the range of ±1%. The research conducted in this paper can provide a research basis for the efficient exploitation of low-flow ocean current energy.

Distribution grid resiliency enhancement is urgently needed in coastal communities, given the severe power outages induced by natural disasters, such as hurricanes, floods, among others. In this paper, a holistic coastal community resiliency enhancement framework is implemented through multiple networked microgrids (MGs) surrounding marine energy resources (MERs) and energy storage units (ESUs) with minimum capacity requirements. Particularly, the real-time sectionalization scheme of coastal communities is determined online driven by an optimization algorithm to maximize the load restoration during and after severe power outages, and more importantly, to ensure operational continuity in coastal communities, the distributed and resilient control schemes are developed at the MER asset level in coordination with system-level reconfiguration plans to enable autonomous and networked MGs. Further, based on the proposed networked MGs control schemes, system stability is evaluated considering various operation modes. Finally, the effectiveness of the proposed framework is validated using a 13-bus coastal community distribution feeder test system.

Wave Energy Converters (WECs) with optimised geometries and control systems have been developed in recent years to advance marine energy technologies towards commercialisation. In particular, a number of WEC hull geometry optimisation studies have been performed, due to the high cost reduction potential associated with the device structure. However, no standard and consistent method has been established for this purpose. For example, different optimisation formulations (single-objective and multi-objective), have been used, applying different optimisation algorithms. Additionally, a range of objective functions have been employed, where power maximisation has been represented through a variety of metrics, and cost minimisation expressed with diverse cost proxies. The goal of this study is to address the challenge of finding a suitable optimisation problem formulation with single-objective or multi-objective implementations, and the respective objective functions, that support the exploration of shapes that reduce the levelised cost of energy. Results show that submerged surface area cost proxies are more suitable for this purpose than volume-based cost proxies. Results from a multi-objective optimisation formulation can provide a good understanding of the solution space, whereas results from single-objective studies can be used for seeding these multi-objective optimisation approaches.

This work determines the variation in the fatigue loading on a tidal turbine at two depth positions and two different locations within a site. Site data were obtained at the European Marine Energy Centre, EMEC, test facility in Scotland, which has been compiled at the University of Edinburgh. The turbine modelled is the 18m Diameter DEEP-gen 1MW horizontal axis turbine. A blade element method is combined with a synthetic turbulence inflow to determine forces along the blade over a period of five tidal cycles. The focus is on establishing the difference between the loads at one tidal site, with an emphasis on the variety of turbulent conditions, with the onset flow fluctuations as great as 17% and the average integral lengthscales varying from 11 to 14 m at hub height. Fatigue loading is assessed using damage equivalent loads, with a 30% variation between turbine positions and 32% between turbine locations within a site, for one design case. When long term loading is assessed, a 41% difference is found for aggregated loads for a near surface turbine and a 28% difference for a near bed turbine.

The whole energy system requires renewables that scale and produce reliable, valuable energy at an acceptable cost. The key to increasing the deployment of ocean energy is bringing down development and operating costs. This paper proposes a structured approach to innovation in ocean energy systems that would spur innovation and expand the market for ocean energy. This approach can be used by a wide range of stakeholders—including technology and project developers and investors—when considering creating or improving designs. The Structured Innovation design tool within the DTOceanPlus suite is one of a kind beyond the current state-of-the-art. It enables the adaptation and integration of systematic problem-solving tools based on quality function deployment (QFD), the theory of inventive thinking (TRIZ), and the failure modes and effects analysis (FMEA) methodologies for the ocean energy sector. In obtaining and assessing innovative concepts, the integration of TRIZ into QFD enables the designers to define the innovation problem, identifies trade-offs in the system, and, with TRIZ as a systematic inventive problem-solving methodology, generates potential design concepts for the contradicting requirements. Additionally, the FMEA is used to assess the technical risks associated with the proposed design concepts. The methodology is demonstrated using high-level functional requirements for a small array of ten tidal turbines to improve the devices layout and power cabling architecture. The Structured Innovation design tool output comprises critical functional requirements with the highest overall impact and the least organisational effort to implement, along with appropriate alternative solutions to conflicting requirements.

International audience; Ocean eddies, as a ubiquitous phenomenon of the global ocean, are extremely important for ocean energy and material exchanges. Therefore, efficient eddy detection and tracking are crucial for advancing our understanding of ocean dynamics. This work presents a framework for automatic ocean eddy detection and tracking by leveraging state-of-the-art machine learning algorithms. First, we propose a new convolutional neural network model for multieddies detection. This model is capable of extracting accurate boundary information of eddies and fitting the gap between semantic context and sea surface height (SSH). Second, a tracking algorithm is designed to track eddies lasting a number of days and provide visualization of the dynamical processes governing eddies’ movements. Finally, we have made our data set publicly available, which is named SCSE-Eddy and can be used as a benchmark to evaluate the performances of artificial intelligence (AI)-based eddy detection methods. The data set covers daily remotely sensed SSH data located in the South China Sea and its eastern sea areas over a period of 15 years. The experimental results show that our methods achieve promising performances compared to existing approaches, especially for the eddies with indistinct geographical border. We believe that this work opens a new avenue for oceanographers to better discover and understand the physical properties of ocean eddies.

This paper are concentrated on low-speed surface-mounted permanent magnet synchronous generator (LS-SMPMSG) electromagnetic design using finite-element (FEM)-based method. Introduced LS-SMPMSG as an important generator in the industry is utilized in marine energy conversion (MEC) and tidal energy conversion (TEC) systems. The main feature of the designed LS-SMPMSG exhibited is its ability to generate electrical power in MEC and TEC systems at a low speed of approximatively 100 rpm. In this paper, a new slot structure for LS-SMPMSG has been proposed to enhance the LS-SMPMSG performance. The FEM analysis and comparing results shows that the new slot structure reduced the torque ripple and the cogging torque equal to 19.54% and 87.5%. respectively. Also, it influenced the LS-SMPMSG Joule losses by reducing it close to 16.1%. Another advantage of the new slot structure of LS-SMPMSG is its easy construction and assembly. The FEM analysis as a powerful method validates the advantages of the proposed structure.

Paper: 19th International Conference on Renewable Energies and Power Quality (ICREPQ’21) Almeria (Spain), 28th to 30th July 2021 [Abstract] The objective of this paper is to examine the importance of independent arrays in the offshore renewable energy farms. In this context, several scenarios have been contemplated for a floating offshore renewable energy farm: a farm only using floating wave energy; a farm only using floating offshore wind energy; and a farm composed by floating wave energy and floating offshore wind energy installed in independent arrays. The article proposes a method to calculate the main economic parameters and decide their economic feasibility. A hypothetic offshore renewable energy farm located in the Galicia region (Spain) has been studied as case of study. Results show which of the scenarios has the best economic results. This method is worthwhile to compare different floating offshore renewable energy technologies in economic terms and help in the decision making of this new emerging sector that can help to rebuild Europe in the post-pandemic period. This research was funded by Project PID2019-105386RA-I00 “Design of a tool for the selection of offshore renewable energy locations and technologies: application to Spanish territorial waters (SEARENEW)”, financed by Ministerio de Ciencia e Innovación – Agencia Estatal de Investigación/10.13039/501100011033

To our knowledge, this paper represents an initial study of a novel concept in freshwater and lithium extraction from desalination powered off-grid by marine renewable energy sources. The project's ...

In the past decade, ocean and marine waves like other renewable energy sources attracted attention due to its high energy density. The most important part of a wave energy converter (WEC) is power take-off (PTO) system. In this study, a proper hydraulic power take-off system for centipede WECs has been evaluated and analyzed in experimental scale. Experimental analysis has been done in dry conditions. Important parameters are resistant load of rheostats and the opening percent of the flow control valve. System input is the wave force, which is modeled as an external mechanical force applied to the end of the lever. Resistant load of rheostats is changeable in the range of 9.5 to 55 ohms. In addition, according to the range of valve opening, six positions are selected to study. Results in this research show that, as resistance load increases, output power and efficiency, are enhanced significantly. On the other hand, in all the resistive loads tested, there is a maximum point (2 rev. valve opening) for efficiency, which shows the positive effect of controlling the input flow to the Hydro Motor (HM). The efficiency in this position of the flow control valve opening has enhanced by 40% compared to neighbor situations.

Regarding the interest in renewable energies, several sources of energy production have been studied and still under improvement. In this work, we are interested in harnessing marine energy currents exploiting the hydrokinetic turbines. The purpose of this study is to provide a comprehensive assessment of the hydrodynamic loads of a 3-blade horizontal-axis marine turbine using a rotor model adapted to the Moroccan potential. For that, the Blade Element Momentum (BEM) is used to calculate the hydrodynamic loads, to estimate the energetic performance, and to determine the blade optimal parameters for a turbine. In additions, the resulting equations are solved in order to obtain the hydrodynamic loads. For validation, a comparison of pressure coefficients along the chord length was made with the results of the Blade software. The Computations were accomplished for a specific NACA profile. Keywords: Marine current turbine, BEM theory, Hydrokinetic turbine, Hydrodynamics performance

Ocean state estimation is a basic problem in the field of ocean engineering. Under the trend of data-driven, the development of intelligent ship decision-making, ocean energy system design and other aspects, are inseparable from the estimation of wave parameters in the ocean area. In recent years, researchers have developed remote sensing technology to monitor ocean waves. However, sensor-based methods all have a key limitation, which is high cost and fault worry. More importantly, one major limitation exists in current research: due to lack of change information and relying on a single feature of spatial data, the final predictive results are inaccurate. Adopting a 3D Convolutional Neural Network is a possible solution to improve the detection accuracy. Unfortunately, it cannot be deployed in the ocean environment due to lack of physical network connections. To resolve these issues, we develop a light-weight version of 3D Convolutional Neural Network, namely a low-cost, high-accuracy detection scheme to foresee ocean wave parameters using a 3D Mobile Convolutional Neural Network technique called iOceanSee in the marine environment. iOceanSee employs a mobile terminal composed of low-cost measuring equipment and non-interference (except light) device-an RGB camera to collect video data in real time. It extracts both space and time features through three-dimensional depthwise separable convolutions. More specifically, iOceanSee is able to capture the encoding motion information from multiple adjacent frames of the video, according to which period and height of the waves being evaluated. Our experimental results conclude that iOceanSee obtains comparable performance to 3D Convolutional Neural Network and outperforms other models in terms of measurement accuracy in the marine environments.

Economic Model Predictive Control (EMPC) has recently been researched in many areas, especially in terms of energy. The development of advanced control algorithms has promoted the cost reduction of marine energy generation and improved the efficiency and reliability of marine current turbines. By reducing the loss on the marine turbine system, better economic indicators can be achieved. Based on this, the maximum marine power can be captured such that the entire marine current turbine system can obtain maximum economic benefits. In this paper, it is mainly based on the economic model predictive control framework to optimize the ocean current turbine power generation system. The system index is directly used for the objective function of the EMPC problem, as EMPC has the advantage of dealing with system constraints and cost functions. Compare the performance of the proposed control framework with the performance of commonly used basic MPC controllers, simulation results show that the proposed controller can reduce the loss of the turbine system and gearbox, indicating that more energy capture can be obtained for the system to achieve better economic effects.

Despite the fact that the ocean contains extensive undeveloped resources and energy, it is still being underutilized owing to the current technical flaws, such as low conversion efficiency and complex manufacture. Compared to an electromagnetic generator (EMG), a triboelectric nanogenerator (TENG) has advantages in harvesting the flow energy, particularly in the low frequency range. As a rapid development in TENG for utilizing the ocean energy, it is necessary to summarize its periodic progress. In this review, the recent research achievements of TENG in the ocean energy field are reviewed, which concentrate on the optimized structural design and working mechanism in macro-scale blue energy and small-scale marine sensing systems. First, the performance comparison of TENG and EMG is conducted. Then, the latest achievements of the three types of devices, namely water-involved TENG, non-water-involved TENG and hybrid TENG, are summarized. Next, the self-powered small-scale marine sensing system based on TENG for ocean environmental monitoring and water treatment is exhibited. Finally, we summarized the prospects and challenges of the macro-scale blue energy and small-scale marine applications with TENG.

Morocco has an exceptional maritime potential especially on its two 500-km Mediterranean and 300-km Atlantic coastlines. The assessment of this potential for marine currents, wind and temperature is largely necessary for the various activities related to the coastline: fishing, exploitation of aggregates, tourism, transport services, desalination and marine renewable energies. Morocco is engaged in a policy of preservation of the environment, the fight against global warming and reducing the emission of greenhouse gases. It is reviewing its 'electric mix' and promoting all renewable energies including marine energy. The results of this study show clearly that Morocco can boast of the potential of its Atlantic and Mediterranean coasts, thanks to the strong winds that blow in the North Atlantic and around the city of Dakhla, at sea currents speeds in vicinity of the Strait of Gibraltar and the difference in temperature between the surface and deep sea. We are particularly interested in the study of the behavior of the marine current, temperature and wind. This is based on monthly data provided by a credible website with free access and statistics from the MATLAB Software.

The star herringbone gear transmission system has a high load-carrying capacity, and is widely used in aviation, marine power drives, off-road vehicles, and hybrid electric-drive vehicles. Vibration and noise are the key concerns with this transmission system. The lumped mass method was adopted to establish the dynamic model and equations of this system. The modes of the system were analyzed and classified, and the eigenvalues and their multiplicities were determined. The results showed that the system has four typical vibration modes: (1) a lateral-rotational coupled vibration mode (multiplicity m = 1), (2) star gear compound mode (multiplicity m = N-3, N > 3), (3) center component lateral vibration mode (multiplicity m = 2), and (4) star gear and center gear-coupled mode (multiplicity m = 2). The contribution of this paper lies in the discovery of the coupling vibration modes in the star herringbone gear transmission system and the multiplicities of these modes. This work provides the foundation for further research on vibration suppression for the star herringbone gear transmission system and the theory of planet phasing.

As one of the largest energy-consumption nations, the South Korean government has recently invested in the deployment and commercialization of various renewable energy sources to reduce the environmental impacts of fossil fuel-based energy sources. Thus, in order to investigate the likelihood the government will default on the investment of research and development (R&D) in the renewable energy industry, this study utilizes a system-dynamics approach to develop a default-prediction model based on the Black-Scholes-Merton model, while investigating the interactions of uncertainty factors and the impacts of the probability of default (PD) on renewable energy production and carbon emission reduction amounts from 2017 to 2030. The results of this study indicate that R&D investments in marine energy (2.64%) has a high default risk, while the use of waste energy (46.95 B kg CO2) results in the largest reduction in the amount of carbon emissions. In addition, the results show that the PD of the R&D investment decreases when the uncertainty of the unit price, the R&D investment amount, and the renewable energy production amount have increased. Further, the results of a Monte Carlo simulation indicate that the PD of the R&D investment is not greatly affected by the risk-free interest rate.

Object and purpose of research. This paper discusses the challenge of making eco-friendly marine fuels readily available. The purpose of this study is to estimate the prospects of such fuels as low-sulfur fuel oil, LNG, etc., in Russian shipping industry. Materials and methods. The study discusses main technological and organizational approaches to introduction of such MARPOL-approved eco-protection measures for ships as scrubbers and eco-friendly fuels to Russian shipping practice. Main results. The paper gives the projections for implementation of eco-friendly fuels and scrubbers aboard Russian ships and vessels. Conclusion. The authors suppose that introduction of LNG as fuel to Russian shipping practice would reduce SOX and NOX emissions, as well as provide sufficient fuel supply and replenishment infrastructure for up to 100 newly built Russian LNG-powered sea-going and inland navigation ships, which will certainly reduce environmental footprint of Russian shipping.

A call for flexible power generation for a wide range of applications is gradually increasing, making Small Modular Reactor (SMR) a heat topic, especially for marine power. Unlike normal reactors, marine reactors demand a long lifetime up to 15 years without refueling, a high power-density and also a higher reliability and security. The standard PWR cannot achieve this goal. Here, a new 13 × 13 assembly loaded with Accident Tolerant Fuels (ATFs): U3Si2 – FeCrAl system, is proposed and analyzed on an assembly-level. U3Si2 is one kind of ATFs with high heavy metal density and thermal conductivity. It has a lower parasitic absorption. FeCrAl has a great radiation resistance, corrosion resistance and thermodynamic properties although with serious neutron penalties. It is currently the fastest researched accident tolerant cladding material. The fuel enrichment of this assembly is raised to 13%, prolonging the burnup to up to 95,000 MWD/tU, which means that the reactor can survive for more than 15 years at its rated power density. Using 15 B4C control rods can help achieve the beginning-of-life cool shutdown (K

In order to overcome the electricity demand in the country and in its effort to reduce the greenhouse gas emission and climate change, South African (SA) government is encouraging research in the field of renewable energy (RE). Higher educational institutions in each province are involve in different renewable energy projects found by provincial governments and private companies. This paper presents an evaluation of RE potential sources in the province of KwaZulu-Natal (KZN). It is found that KZN province has a RE potential exploitable of about 45 GW divided into 53.63 % of global normal irradiance (GHI), 23.28 % of direct normal irradiance (DNI), 13.52 % of wind energy, 9.51 % of geothermal and 0.06 % of biomass energy that can be converted into electricity, ocean energy and hydropower excluded. With the results exposed in this article, further investigations can be done to determine the net electrical energy that can be produced from those sources for design of RE systems and energy harvesting as well as the appropriate areas to install RE systems. Keywords: Potential energy, Solar energy, Wind energy, Biomass energy, Geothermal energy

Vertical mixing is important in the ocean for maintaining its stratification, redistributing temperature and salinity, distributing nutrients and pollutants, and the energy cascade. It plays a key role in ocean energy transport, climate change, and marine ecosystems. Getting the mixing right in ocean circulation and climate models is critical in reproducing ocean and climate physics. Ocean models, like the Regional Ocean Modeling System (Rutgers ROMS 3.4), provide several options for determining vertical mixing through the vertical mixing parameterization schemes. To evaluate which of these methods best reproduces realistic vertical mixing by internal tides, simulations of baroclinic tides generated by a seamount were performed using seven different vertical mixing parameterizations: Mellor-Yamada 2.5 (MY), Large-McWilliams-Doney’s Kpp (LMD), Nakanishi-Niino’s modification of Mellor-Yamada (NN), and four versions of Generic Length Scale (GLS). The GLS versions in ROMS 3.4 severely overmixed the water column within a day and were not considered realistic. We suspect that a coding error has been introduced for it. We focused on the performance of the MY, LMD, and NN vertical mixing parameterizations. LMD was found to overmix the water column. The performance of MY and NN were nearly equivalent and both well reproduced the observed velocity and diffusivity fields. NN performed slightly better by having a lower rms for M2 and K1, less benthic mixing, more mid-water column mixing, less overmixing, and fewer extremely high diffusivities (> 1 m2 s−1).

Indonesia has many archipelagos with long and complex coastlines that connect to the Pacific Ocean in the northeast and to the Indian Ocean in the southwest. Several species of fish in this area are easily attracted to fish aggregating devices (FADs), which are a type of environmentally friendly artificial ocean infrastructures. We investigated characteristics of tidal currents in the Indonesia archipelagos and suitably designed a small-scale tidal-current turbine with an FAD to independently supply electric power to the archipelagos. Moreover, we estimated the amount of electric power generated by the setup. The results indicate that the tidal currents in narrow straits are considerably higher in archipelagos, such as the Maluku and Nusa Tenggara Islands including Bali Strait. Lombok Strait also exhibited the maximum tidal-current velocity of 4 m/s. The small-scale tidal-current turbine was theoretically and numerically designed to utilize the tidal current specific to the Indonesian archipelagos. We estimated the amount of electric power generated by the 2.2-m-diameter turbine with 10-kW class to adjust to the specific archipelagos.

The performance assessment of industrial marine energy converters involves the integrated treatment of their hydrodynamic design and the optimization of their device hulls. Nowadays, such tasks require extensive experimental work and simulation plans, consuming considerable resources and time. In this comprehensive review of integrated approaches to numerical and experimental testing, the advantages and disadvantages of existing tools, from full-scale prototype and wave tank models to Computational Fluid Dynamics (CFD) and potential flow simulations, are all analysed. Likewise, current challenges such as experimental scale effects, numerical viscosity, and turbulence treatment are all studied. The novelty of this research is an integrated approach that employs experimental wave tank tests to validate a numerical wave tank model based on CFD that serves to calibrate a fast potential flow solver with Morison's correction terms. The model allows running, on tight resources, the necessary simulation for the design and optimisation of marine energy converters under multiple sea state conditions. Given the operating regimes of conventional marine energy converters, the results show that the influence of turbulence may be small, due to the unsteady nature of the oscillatory boundary layer flows.

Variability in the predicted cost of energy of an ocean energy converter array is more substantial than for other forms of energy generation, due to the combined stochastic action of weather conditions and failures. If the variability is great enough, then this may influence future financial decisions. This paper provides the unique contribution of quantifying variability in the predicted cost of energy and introduces a framework for investigating reduction of variability through investment in components. Following review of existing methodologies for parametric analysis of ocean energy array design, the development of the DTOcean software tool is presented. DTOcean can quantify variability by simulating the design, deployment and operation of arrays with higher complexity than previous models, designing sub-systems at component level. A case study of a theoretical floating wave energy converter array is used to demonstrate that the variability in levelised cost of energy (LCOE) can be greatest for the smallest arrays and that investment in improved component reliability can reduce both the variability and most likely value of LCOE. A hypothetical study of improved electrical cables and connectors shows reductions in LCOE up to 2.51% and reductions in the variability of LCOE of over 50%; these minima occur for different combinations of components. The research leading to this publication is part of the DTOceanPlus project which has received funding from the EuropeanUnion's Horizon 2020 research and innovation programme under grant agreement No 785921. Funding was also received from the European Community's Seventh Framework Programme for the DTOcean Project (grant agreement No. 608597). The contribution of Sandia National Laboratories was funded by the U.S. Department of Energy's Water Power Technologies Office. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government. The image of the RM3 device, in Fig. 7, was reproduced with the permission of Sandia National Laboratories

Ocean energy technologies are still at an early stage of development; only a handful of concepts are being invented and tested worldwide. The environmental impact of these devices is not always taken into account, mainly because of the prevailing uncertainty regarding its assessment. It is vital that attention is paid to the mitigation of potential negative impacts on physical and biotic marine systems. In this study, the direct and indirect effects of ocean energy projects on biophysical systems, and their interactions, are identified from an analysis of current literature on the subject. A tool that could be applied to any ocean energy project at any stage of an EIA is then proposed from a framework designed to evaluate the widely varying impacts of devices. This framework uses a categorisation of the environmental impacts of MRE devices (biophysical, chemical and socio-economic), based on the technology used and the device location. It is hoped that this tool will facilitate the identification of the potential environmental impacts of MRE devices and thus serve as a guide to quantitatively assess these impacts.

With consideration to research nature, scope of available materials and industrial feature, we investigate cultivation of professionals in the three new marine industries such as marine energy, marine bio-industry and submarine hydrothermal deposits development. More specific, we investigate trends of marine science and technology manpower at the national level in Korea nurturing policy to forecast mid and long term expert manpower demand and to respond to trends and forecasts of major fields. Cultivation of necessary professionals is an essential prerequisite for growth of new marine industry and its contribution to national economy. Because the new marine industry was recently introduced, the established system and policies for professionals in science and technology did not reflect demand for this new industry, which requires improvement. Since new marine industry is a new field, it is difficult for customized talent to be supplied directly from existing manpower training system. Therefore, it is necessary to cultivate talented people with fused thinking and ability. In the existing system, it is necessary to strengthen efforts to develop professional manpower with fusion competence, and it is also necessary to make policy efforts to build a new system such as cooperation process.

Owing to the depletion of oil reserves and the low efficiency of traditional deep-water semi-submersible drilling platforms, the application of photovoltaic generation and energy storage systems in marine power systems has been increasingly attracting attention. However, the intermittent and uncertain nature of solar energy brings crucial challenges in maintaining stable and sustainable operations. Furthermore, unlike land-based power systems, the deep-water semi-submersible drilling platform depends on a dynamic positioning system to be fixed in an area of deep water for producing oil, but irregular and stochastic waves make the outputs of a dynamic positioning system uncertain, increasing the difficulty and complexity of energy management. This paper develops a novel hybrid day-ahead probabilistic scheduling method to reduce the total fuel cost of the whole system and improve the energy efficiency; the method combines Taguchi's orthogonal algorithm with particle swarm optimization and a probabilistic load flow method. A detailed model of the deep-water semi-submersible drilling platform is established to validate the proposed method, which is compared with various classical methods. With the help of the proposed method, the total operation cost and greenhouse gas emissions are reduced from $7562.52 to $7333.68, and from 18.95 tons to 16.81 tons, respectively. Furthermore, compared to the two-point estimation method, the experimental times drops by half, which minimizes the computational burden. The simulation results clearly demonstrate the necessity for day-ahead energy scheduling, and the advantages of the proposed method.

Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benefits of seawater desalination, the desalination load can be combined with renewable energy sources such as solar energy, wind energy, and ocean energy or with the power grid to ensure its effective regulation. Utilizing energy internet (EI) technology, energy balance demand of the regional power grid, and coordinated control between coastal multi-source multi-load and regional distribution network with desalination load is reviewed herein. Several key technologies, including coordinated control of coastal multi-source multi-load system with seawater desalination load, flexible interaction between seawater desalination and regional distribution network, and combined control of coastal multi-source multi-load storage system with seawater desalination load, are discussed in detail. Adoption of the flexible interaction between seawater desalination and regional distribution networks is beneficial for solving water resource problems, improving the ability to dissipate distributed renewable energy, balancing and increasing grid loads, improving the safety and economy of coastal power grids, and achieving coordinated and comprehensive application of power grids, renewable energy sources, and coastal loads. Keywords: Desalination, Distribution network, Power grids, Multi-source multi-load, Coordinated control

This study explores the effects of black carbon (BC) and sulfate (SO4) on global and tropical precipitation with a climate model. Results show that BC causes a decrease in global annual mean precipitation, consisting of a large negative tendency of a fast precipitation response scaling with instantaneous atmospheric absorption and a small positive tendency of a slow precipitation response scaling with the BC-caused global warming. SO4 also causes a decrease in global annual mean precipitation, which is dominated by a slow precipitation response corresponding to the surface cooling caused by SO4. BC causes a northward shift of the intertropical convergence zone (ITCZ), mainly through a fast precipitation response, whereas SO4 causes a southward shift of the ITCZ through a slow precipitation response. The displacements of the ITCZ caused by BC and SO4 are found to linearly correlate with the corresponding changes in cross-equatorial heat transport in the atmosphere, with a regression coefficient of about −3° PW−1, implying that the ITCZ shifts occur as manifestations of the atmospheric cross-equatorial heat transport changes in response to the BC and SO4 forcings. The atmospheric cross-equatorial heat transport anomaly caused by BC is basically driven by the BC-induced interhemispheric contrast in instantaneous atmospheric absorption, whereas the atmospheric cross-equatorial heat transport anomaly caused by SO4 is mostly attributable to the response of evaporation. It is found that a slab-ocean model exaggerates the cross-equatorial heat transport response in the atmosphere and the ITCZ shift both for BC and SO4, as compared with an ocean-coupled model. This underscores the importance of using an ocean-coupled model in modeling studies of the tropical climate response to aerosols.

In the development of ocean energy technologies, full-scale sea trials have proven technically challenging and expensive. As a contribution to the development of flexible, reliable, and affordable measurement systems for such sea trials, this paper presents and evaluates a portable data acquisition system. The system offers a cheap and flexible option for when and where signal infrastructure at site is not available. It is battery powered and consists of a sensor system and a logger unit. The sensor system is placed inside the object of study, which for this application is a wave power generator standing on the seafloor. The logger unit, which contains a logger with integrated data storage and a battery, is placed outside the object of study in a submersible and retrievable vessel. Sensor output is carried with 4–20-mA current signals between the sensor system and the logger, which makes the system directly compatible with a wide range of industrial sensors. For the specific setup implemented in this paper, the sensor system was used to measure voltage and current inside the generator. Beyond this, the system is designed to be adaptable for a wider range of sensors, with 16 individual signals and a sampling frequency up to 1 kHz. The custom logger is programmable and offers many options to apply different logging schedules and to limit the sensor system power supply accordingly. Evaluations show that the implemented system offers 5–22 weeks of 1-kHz and 16-b monitoring of 16 signals, depending on a chosen logging schedule. Suggestions are also given for how to raise the operation time up to 50 weeks. The system has been tested offshore for the collection of power production data from two wave energy converters, with good results.

Purpose High-quality development of marine economy is a new concept put forward in response to the current national strategy in China. The purpose of this paper is to thoroughly understand the connotation and significance of high-quality development of marine economy through literature review, and further analyze the prospects for further research. Design/methodology/approach The authors first use the information visualization technology of CiteSpace to present a systematic review of the published literature from 2010 to 2019. Then, the authors analyze the researches on high-quality development of marine economy in terms of connotation, evaluation dimension, development path and guarantee mechanism. Findings Analysis results show that there is still insufficient understanding of the differences and links between the high-quality development of marine economy and the construction of marine power, intelligent ocean and transparent ocean. Originality/value Based on a thorough understanding of the subject, this paper puts forward the direction of further research on evaluation index system, path design scheme and policy system construction for high-quality development of marine economy.

Renewable energy usually refers to those natural resources of energy whose availability does not decrease with its usage. Various sources of renewable energy are there such as solar energy, wind energy, marine energy. The Marine Current Turbine (MCT), is an exciting proposition for the extraction of tidal and marine current power. CFD simulation is being widely used in the research on marine current turbines. The present research also represents a step in this direction. Solution of incompressible unsteady Navier-Stokes (N-S) equations is required in the numerical simulation of flow around MCT. Large Eddy Simulation (LES) has been opted which fully resolves the energetic turbulent flow structures and models only the sub-grid scale turbulence. IB method has been used to enforce the boundary conditions on complex geometry. Due to computational limitations we have been able to perform only a coarse grid LES of the marine turbine for specific operating conditions. Nevertheless, the results provide insights into the flow structures around the marine turbine. Analysis shows that the effect of vorticity diminishes after 11R from the turbine rotor blade. However, the velocity deficit region remains until the end of the domain used in our simulations which is 10D distance downstream of the rotor blades.