Search

The shipping industry is a significant source of global greenhouse gas emissions, so finding sustainable and low-carbon alternative fuels is crucial to reduce its environmental impact. Hydrogen is emerging as a promising fuel for shipping due to its high energy density, zero emissions, and the possibility of production from renewable sources. However, the use of hydrogen as a fuel in shipping requires significant infrastructure development and technological advances in hydrogen production, storage and transportation. In addition, the cost and availability of hydrogen fuel remain the main barriers to its widespread adoption in shipping. Despite these challenges, the potential benefits of using hydrogen as an environmentally friendly fuel for shipping make it an area of growing interest and investment. Hydrogen fuel is increasingly becoming a promising alternative to traditional fossil fuels for ships. It is a clean and renewable energy source that produces only water vapor as a byproduct, making it a desirable solution for reducing greenhouse gas emissions and mitigating climate change. Six percent of the world's natural gas and two percent of coal are currently used to produce hydrogen. Hydrogen can be used as a zero-emission fuel, but the production of the gas itself is not a low-carbon process if fossil fuels are used to produce it. Nevertheless, experts believe that hydrogen is a fuel solution for shipping. Even today, leading scientists and experienced ship operation and design professionals are calling for the wider use of hydrogen as a fuel, which will ultimately help the maritime industry achieve its goal of reducing emissions through the use of non-fossil fuels. This article explores the potential of hydrogen fuel for ships, including its benefits, challenges and current status., Судноплавна галузь є значним джерелом глобальних викидів парникових газів, тому пошук стійких і низьковуглецевих альтернативних видів палива має вирішальне значення для зменшення її впливу на навколишнє середовище. Водень стає перспективним видом палива для судноплавної галузі завдяки своїй високій енергетичній щільності, нульовим викидам і можливості виробництва з відновлюваних джерел. Однак використання водню як палива в судноплавстві потребує значного розвитку інфраструктури і технологічного прогресу у виробництві, зберіганні та транспортуванні водню. Крім того, вартість і доступність водневого палива залишаються основними бар'єрами на шляху його широкого впровадження в судноплавстві. Незважаючи на ці виклики, потенційні переваги використання водню як сталого палива для судноплавства роблять його сферою зростаючого інтересу та інвестицій. Водневе паливо дедалі стає багатообіцяльною альтернативою традиційному викопному паливу для суден. Це чисте і поновлюване джерело енергії, яке виробляє лише водяну пару як побічний продукт, що робить його бажаним рішенням для скорочення викидів парникових газів і пом'якшення наслідків зміни клімату. Шість відсотків світового природного газу і два відсотки вугілля наразі йде на виробництво водню. Водень можна використовувати як паливо з нульовими викидами, але при цьому виробництво самого газу не є низьковуглецевим процесом, якщо для його виробництва використовується викопне паливо. Тим не менш, на думку експертів, водень – це паливне рішення для судноплавства. Вже сьогодні провідні науковці та досвідчені фахівці у сфері експлуатації та проєктування суден закликають до більш широкого використання водню як палива, що в кінцевому підсумку допоможе морській індустрії досягти своєї мети щодо скорочення викидів за рахунок використання невикопних видів палива. У цій статті досліджується потенціал водневого палива для суден включаючи його переваги, виклики та поточний стан.

Nowadays, an increase in energy demand, environmental concerns, and the shortage of fossil fuel resources have made energy management researchers explore alternative resources for clean and renewable energy resources. The simultaneous incorporation of a comprehensive set of technical, economic, environmental, and social attributes in decision-making processes is recommended to improve the efficiency and effectiveness of sustainable decisions on energy resource planning. To tackle this challenge, an efficient method is proposed based on the Simultaneous Evaluation of Criteria and Alternatives (SECA) for the optimal selection of renewable energy resources. In the SECA technique, criteria and alternative evaluations are performed simultaneously. The proposed assessment framework is applied in Iran's electricity industry as a real case study, and a two-round fuzzy-based Delphi technique is also adopted to extract the assessment criteria from the experts' opinions. Moreover, the management insights are inferred from sensitivity analysis. According to the study results, solar, wind, biomass, hydroelectric, hydrogen, geothermal, and marine energy resources are sorted in descending order of priority. Finally, the best composite option of sustainable energies encompassing a combination of solar, wind, and biomass energy resources concludes the study.

In this paper, considering the oceanic multiple degree of freedom motion, a double stator linear-rotary permanent magnet (DSLRPM) generator with Halbach PM array is proposed for direct drive ocean energy conversion. It focuses on the power maximization generation resulting in a highly optimized DSLRPM generator to improve the generated power of the ocean energy conversion system in complex ocean condition. Based on the power-oriented design concept, the whole design process is divided into two steps. In the initial design procedure, the operating domain design is conducted, and the design point is selected. In the optimization design procedure, the non-dominated sorting genetic algorithm II (NSGA-II) coupled with response surface methodology (RSM) and sensitivity analysis is proposed to be as an optimization design technique. Finally, a prototype based on the optimized results is manufactured. The experimental results agree with the simulated result, and they both reveal that the proposed method can offer an effective design and optimization for the DSLRPM generator, where the multiple oceanic motions and complex operating conditions are considered.

Water-solid triboelectric nanogenerators (TENGs), as new energy collection devices, have attracted increasing attention in ocean energy harvesting and self-powered sensing. Polyacrylic acid (PAA) coating, usually used on the surface of marine equipment, has the property of anti-aging and anti-wear but limits triboelectrical output when used with TENGs. In this paper, polyacrylic acid coating was modified with fluorinated polyacrylate resin (F-PAA) to increase its triboelectrical output, by 6 times, and also to increase its anti-corrosion property. In addition, the corrosion resistance property can be further enhanced by cathodic protection using the electrical output generated by the water-flow triboelectrical energy transfer process. Given their easy fabrication, water-flow energy harvesting, and corrosion resistance, PAA/F-PAA coating-based TENGs have promising applications in river and ocean energy collection and corrosion protection.

The depletion of fossil fuel and their impact on the environment due to continual usage for our ever-increasing power needs has forced us to look pro-actively towards other renewable forms of clean energy like wind, solar, ocean energy, etc. Amongst all renewable sources of energy, solar energy is abundantly available throughout the world and can meet the energy needs of our planet if appropriately harnessed. Solar thermal collectors are used to collect solar thermal energy, and then it is transferred to the fluid. The fluid may be air, water, oil, etc. depending on the application. Many researchers are working towards performance enhancement of solar thermal collectors. This article concentrates on solar air collectors and different types of modifications made in the recent past to improve its efficiency. This study is an attempt to summarize and present solar air heaters and various modifications for performance enhancement. The effect of modifications on the Nusselt number, friction factor, and thermohydraulic performance of the solar thermal collector is reported. The present article also discusses the effect of impingement of air on the device thermal efficiency and the geometric modifications. This paper will enable researchers working in this field to get a summary of important work done related to solar thermal collectors.

In this investigation, instrumented mobile platforms are used to spatially map the turbulent flows in Grand Passage, one of the Bay of Fundy's more energetic tidal channels in Nova Scotia, Canada. The aim is to characterize the flow around the PLAT-I floating tidal energy platform developed by Sustainable Marine Energy Canada (SMEC). GPS-tracked surface drifters equipped with fast-sampling acoustic Doppler current profilers (ADCPs) provide turbulence-resolving vertical profiles of velocity and turbulent kinetic energy dissipation rate along drifter trajectories, while vessel-mounted ADCP transects complement the mean flow velocity measurements. These data are used to construct tridimensional quasi-synoptic maps of mean velocities and turbulence parameters for several stages of the tide around PLAT-I's location including peak ebb and flood currents. The data set includes measurements under natural flow conditions, and while the turbines installed on PLAT-I were both not operational and operational. The measurement techniques and resulting maps successfully capture the spatial and temporal structure of the flow for unsteady conditions for various tidal conditions. The combined wake of the four 6.3 m operational PLAT-I turbines was measured for a single tidal stage. Closer to the turbines, the vertical extent of the wake is about 6 m (approximately one turbine diameter), increasing with distance downstream, while the maximum observed velocity deficit is 26% relative to not operating conditions, decreasing with distance downstream.

In light of climate change and greenhouse gas reduction, countries around the world are doing their part to develop various types of eco-friendly energy. In this context, the Shihwa Tidal Power Plant is an advanced energy generation infrastructure which uses the resources of the sea, a project that pioneers and practices low-carbon, green growth engineering. Not only as an advanced energy generation infrastructure but also it is an eco-friendly infrastructure that resurrected ‘the dead lake’, which had suffered extreme water pollution due to cutoff in seawater circulation after the completion of the tide embankment in 1994. By circulating the water of the lake, new mud flats have appeared in the upstream area, an area once submerged due to the embankment. These new mud flats are providing new shelters for various organisms, thus transforming the lake into an eco-friendly, life-giving one. Most tidal power plants are difficult to construction due to geological features. The Sihwa tidal power plant was developed harmoniously by utilizing the unique geological features and tidal power plant principles on the West coast of the Korean peninsula. Shihwa Tidal Power Plant is a special and differentiated development example of renewable energy production and environmental improvement along with the significant water quality improvement effect of Shihwa Lake due to increased seawater exchange rates. This article therefore presents the review of Shihwa Lake’s environmental issues and eco-friendly energy production process with the aim to identify the good practices, the challenges as well as the lessons learnt from their experience. This development will be another case of a country seeking to develop new marine energy. This is also a good practice of improving the environment of freshwater lakes in coastal areas.

The Lagrangian eddies in the western Pacific Ocean are identified and analysed based on Maps of Sea Level Anomaly (MSLA) data from 1998 to 2018. By calculating the Lagrangian eddy advected by the AVISO velocity field, we analyzed the variations in Lagrangian eddies and the average transport effects on different time scales. By introducing the Nino coefficient, the lag response of the Lagrangian eddy to El Nino is found. These data are helpful to further explore the role of mesoscale eddies in ocean energy transfer. Through normalized chlorophyll data, we observed chlorophyll aggregation and hole effects caused by Lagrangian eddies. These findings demonstrate the important role of Lagrangian eddies in material transport. The transportation volume of the Lagrangian eddy is calculated quantitatively, and several major transport routes have been identified, which helps us to more accurately and objectively estimate the transport capacity of Lagrangian eddies in the western Pacific Ocean.

New approaches need to be taken into account in adopting the configuration of residual heat recovery systems, design, operation and control and to consider equipment and the energy conversion process in the perspective of integrated systems in order to increase measurable energy efficiency in existing marine energy systems as well as other new systems.

Air gun arrays are often used in marine energy exploration and marine geological surveys. The study of the single bubble dynamics and multibubbles produced by air guns interacting with each other is helpful in understanding pressure signals. We used the van der Waals air gun model to simulate the wavelets of a sleeve gun of various offsets and arrival angles. Several factors were taken into account, such as heat transfer, the thermodynamically open quasi-static system, the vertical rise of the bubble, and air gun post throttling. Marine vertical cables are located on the seafloor, but hydrophones are located in seawater and are far away from the air gun array vertically. This situation conforms to the acquisition conditions of the air gun far-field wavelet and thus avoids the problems of ship noise, ocean surges, and coupling. High-quality 3D wavelet data of air gun arrays were collected during a vertical cable test in the South China Sea in 2017. We proposed an evaluation method of multidimensional facial features, including zeropeak amplitude, peak-peak amplitude, bubble period, primary-to-bubble ratio, frequency spectrum, instantaneous amplitude, instantaneous phase, and instantaneous frequency, to characterize the 3D air gun wave field. The match between the facial features in the field and simulated data provides confidence for the use of the van der Waals air gun model to predict air gun wavelet and facial features to evaluate air gun array.

Tidal turbine applications will place composite materials such as glass-fibre-reinforced polymers (GFRPs) and carbon-fibre-reinforced polymers under surprisingly high pressure due to the significant water depths they operate in (to depths of 50 m). The technical reliability of tidal turbines must be guaranteed despite the high dynamic loads resulting from the combination of plant operation, wind and waves with irregular swell. These external effects could lead to operation downtime and accelerated degradation. Research has already established that (unpressurised) moisture saturation is detrimental to both the tensile and fatigue strengths of a GFRP material compared with its dry laminate performance. This degradation has been shown to be stress dependent. It is possible that hydrophobic coatings could help protect the material while in service. Therefore, two commercially available coatings were applied to five variations of composite materials. These materials are commonly used in tidal and wave turbine blades, as they have excellent corrosion resistance and mechanical properties. All five were subjected to the same conditioning processes: non-pressurised and pressurised immersion conditioning in water. A glass-fibre epoxy (Ampreg) composite, along with a glass-fibre powdered epoxy composite, a glass-fibre polyether ether ketone composite and a carbon-fibre powdered epoxy composite, was investigated. The glass-fibre epoxy (Ampreg) was also subjected to static/fatigue tensile tests.

This article proposes a multiport magnetic bus (MMB)-based novel wind-wave hybrid ocean energy technology (HOET). The ocean waves are mixed frequency waves and generate unique frequency spectra. The wave energy converters (WECs) connected to the linear permanent magnet generators generate voltages with varying amplitudes and frequencies due to the variation of the wind speed and direction. The proposed MMB of the proposed compact wind-wave HOET can provide galvanic isolation and allow a high-frequency operation of the MMB. A decoupled voltage and current control architecture is proposed to regulate the voltage and current waveforms in the high-frequency inverter modules of the MMB that can integrate multiple WECs. An Archimedes wave swing-based conversion method is utilized for the modeling and the design of the proposed WEC. A damping controller is designed to extract the maximum power from the irregular waves. For the wind-energy generation system, a doubly fed induction generator-based technology is considered. The simulation and the laboratory-scale experimental results validate the potential and the applicability of the proposed wind-wave HOET as an effective means to harness ocean energy.

Most tidal energy site studies concentrate on resource size; few examine other factors that may be of equal or even greater importance in determining site feasibility for tidal turbine array deployments. These factors include aspects such as electrical grid proximity, water depth, the location of marine protected areas, pre-existing users, environmentally significant regions and other restrictions. Using these factors, a more holistic approach to site selection was conducted for Australian waters using a Multi-Criteria Evaluation (MCE) process. This MCE method uses standardized factors combined with weighted linear combinations to calculate a site suitability index, where each factor is multiplied by a weight of relative importance. A sensitivity analysis on the factor weighting was performed to ensure the suitable selection of weighting factors to reduce conformation bias. The developed MCE model identified three promising locations in Australia, with contiguous areas in regions to the north of Broome Western Australia of 534 km2, the Banks Strait region northeast of Tasmania of 67 km2, and the Clarence Strait located in the Northern Territory of

In this paper, a strategic decision making model for the sustainable development of marine renewable energy is proposed, and a specific application to the United Kingdom (UK) is demonstrated. As an island nation the UK benefits from significant marine energy potential which is providing an increasing contribution to UK's renewable energy portfolio. The paper investigates the question of how decision makers can be aided to reach a decision on which types of marine renewable energy projects should be chosen for development given that strategic energy planning is subject to a number of uncertain parameters and multiple sustainability objectives. In this context, the contribution of this paper lies in the combination of renewable energy portfolio selection and the application of multi-objective methods. Interval coefficient goal programming models are adopted in order to address the impreciseness and uncertainty associated with the goals and coefficients of the models in the context of renewable energy selection. The potential renewable energy projects are clustered in order to aid the decision making process and preferential weight sensitivity methods are employed. Conclusions are drawn for optimistic and pessimistic scenarios in the context of UK marine renewable energy planning.

Reliable protection is the key requirement for modern multi-megawatt‐capacity marine power systems with multiple synchronous generators of various capacities operated in parallel. Outage of the mains or unavailability of the other generators results in momentary overload to the healthy generator(s). Conventional load surge protection relays based on a zero-crossing detection algorithm require a minimum of 10 ms to detect a momentary overload, which could be detrimental for lower inertia/capacity generators. This article presents a novel supervised machine-learning‐based Kalman predictor algorithm that could detect momentary overloads in

This work presents a series of devices that generate renewable energy from the marine environment which, in recent years, have aroused increasing interest. In particular, the main types of floating wind generators and marine current turbines are described. Over time, some of these floating generators have evolved in various hybrid modalities, integrating different generation devices into the same system, wind turbines, marine current turbines, wave energy converters, etc., with the objective of multiplying their generation capacity and optimizing the investment made in the floating system. However, this hybridization offers, in some cases, an opportunity to address the problem of controlling the structural stability of the system. Such stability enhancement has been considered a major challenge since the early days of floating wind turbine design. With this objective, in this work, a specific solution is proposed, consisting of a floating hybrid system composed of a wind generation subsystem and a generation subsystem with two marine current turbines. This proposal allows the development of an integrated control system which deals simultaneously with the structural stability of the system and the optimization of the generation capacity. Additionally, other requirements are also highlighted relating to the achievement of economic viability objectives, considering the reliability and availability of the system in the particularly aggressive marine environment, where maintenance operations are especially costly. In this sense, a model of intelligent integration of the tasks of supervision, diagnosis, and predictive maintenance is proposed.

The serious environmental pollution and energy crisis have become a global issue, which makes it a pressing task to develop sustainable and clean energy sources. There exists a large amount of renewable energy in the ocean; unfortunately, most resources are underutilized. In this work, we demonstrate a performance-enhancing rolling triboelectric nanogenerator (TENG) based on nano-micro-structured polytetrafluoroethylene (PTFE) films. The nano-micro structure on the PTFE surface can increase the effective contact area and enhance the triboelectric effect, which is beneficial to improve the output performance. As a result, the output voltage and output current are 25.1 V and 7.3 μA, respectively. We further investigate the effect of nano-micro PTFE concentration on the output performance. The TENG based on a 45% concentration of nano-micro PTFE presents the maximum output power. Furthermore, this TENG can effectively harvest water wave energy with various amplitudes and frequencies, which has the potential to harvest ocean energy for environmental monitoring.

The liquid-solid triboelectric nanogenerator (LS-TENG) has been demonstrated to harvest energy efficiently through the contact electrification effect between liquid and solid triboelectric materials, which can avoid the wear issue in solid-solid TENG. However, the droplet-based LS-TENG reveals the problems that it generally works with the continuous falling droplets or needs to be fully packaged, which greatly limit its practical application. Here, a droplet-based triboelectric nanogenerator (DB-TENG) with a simple open structure is designed to effectively solve these problems. The nonpackaged DB-TENG can work stably under extreme conditions with high humidity or high concentrations of salt, acid, or alkali solutions, showing the DB-TENGs can be flexibly utilized in all types of working environments with better reliability and lower maintenance costs. It is of great significance that the integrated DB-TENG network array can realize the all-weather ocean energy harvesting. Furthermore, under the simulated ocean wave, a scaled-up DB-TENG with considerable output performance can charge capacitors and drive electrical devices. Overall, the DB-TENG shows many advantages: simple open structure, all-weather working ability, timely supplement of water loss, no tight packaging, wear resistance, suitable for extreme working environments. This work provides a convenient and feasible way toward all-weather wave energy harvesting in real marine environments.

With an increasing demand for ocean resources to fulfil the needs of an ever growing population, humanity has been pushed to utilise the ocean resources. To be successful in these efforts, they hav...

Ocean waves are a valuable resource of renewable energy that can make a significant contribution to the supply of electricity to countries situated offshore when used in great measure. An extensive range of innovations was proposed, investigated, and assessed in some cases under actual ocean conditions. OWC devices are an important class of wave energy method. The majority of designs used in the conversion of wave energy into the sea are OWC. There is a fixed or floating hollow structure in an OWC under the water surface, which pits the air over the inner free zone. The wave action alternately compresses and separates the air that is forced to flow into a turbine together with a generator. A detailed analysis of OWC technologies is discussed in this paper.

Offshore wind and wave energy resources are possibly the last significantly untapped renewable energy resource, and could play a significant role in mitigating the impacts of climate change via the generation of renewable electricity. While often considered independently, there are significant technical advantages to co-deployment of wave and offshore wind technologies, and will be future competition for limited marine real estate, so there is a distinct need to development holistic assessments of these offshore resources. Currently, offshore wind and wave energy resource assessments have been conducted as independent parallel processes, with little interaction with regard to best practices, lessons learnt, or opportunities to create compatible methodologies for future utilization by the broader marine energy sector. Based on the latest technical specifications from the International Electrotechnical Commission, and the highest fidelity publicly available datasets, the offshore wind and wave conditions at the PacWave site off Oregon, USA were quantified. At the 70m depth site, the results clearly show a significant untapped energy resource an annual average wave energy flux of ∼35 kW/m and a mean average wind speed of 7.8 m/s; suitable for significant offshore wind (fixed and floating) and wave energy technology deployment The offshore wind and wave energy resources both show significant seasonal variation, with offshore wind also featuring a consistent daily profile during summer. Finally, opportunities and challenges associated with developing a holistic assessment of offshore marine energy resources were discussed and recommendations provided.

The use of condition monitoring and fault diagnosis (CMFD) in marine power systems significantly influences ship safety. This study divides the development of CMFD for marine power systems into three periods and reviews the content, state and limitations of CMFD research for each period. According to the research achievements and engineering experience of the authors’ team, typical application cases are introduced for CMFD in ships, including CMFD platforms on engineering ships, salvage ships, container ships and ro-ro ships powered by solar photovoltaic systems. Finally, prospective research directions are proposed for CMFD in marine power systems, considering the research status of CMFD and the trend toward intelligent and eco-friendly ships.

In response to the growing interest in offshore wind energy development in California, the U.S. Bureau of Ocean Energy Management delineated three Call Areas for potential leasing. This study provides a comprehensive characterization and comparison of offshore wind power potential within the two Central California Call Areas (Diablo Canyon and Morro Bay) using 12‐ and 15‐MW turbines under different inter‐turbine spacing and wind farm size scenarios. Our analysis shows similar daily and seasonal patterns of wind power produced within the Call Areas, which peak in spring and during evening hours. Per‐turbine power production is higher in the Morro Bay Call Area due to slightly higher hub‐height wind speeds, whereas total power production is higher in the Diablo Canyon Call Area due to its larger size. Turbine type had a negligible impact on average power production per‐unit‐area because while larger turbines produce more power, they require greater inter‐turbine spacing. Combined power production from the two fully built out Call Areas could equal nearly a quarter of California's current annual electrical energy production. A commercial‐scale wind farm with a realized power output of 960 MW would require a footprint of at least half of the Morro Bay Call Area or at least a quarter of the Diablo Canyon Call Area. These results provide guidance on offshore wind development over the Central California Coast, and the framework demonstrated here could be applied to other wind data sets in other regions.

Development of ocean energy conversion technique is a strategic requirement to optimize the energy structure and expand the "blue economic" space. Triboelectric nanogenerator (TENG) provides a potential approach for efficiently capturing wave energy with its unique advantages. Herein, a nodding duck structure multi-track freestanding triboelectric-layer nanogenerator (NDM-FTENG) is developed for ocean wave energy harvesting at a low-frequency range. Configuration parameters including track numbers, connection approach, oscillation frequency, and swing amplitude on electrical output performances of NDM-FTENG are systematically investigated and optimized; the maximum instantaneous power density of 4 W/m3 is obtained by one NDM-FTENG block with 320 LEDs lighted up simultaneously. Overall, NDM-FTENG is proved to be an efficient device for driving small electronics with excellent stability and durability in a real water wave environment, and the power potential can be further magnified by combining more NDM-FTENG devices in parallel to form a network toward large-scale blue energy harvesting.