Journal of Marine Science and Engineering

Editorial

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4 pages, 209 KiB

Open AccessEditorial

Hybrid Systems for Marine Energy Harvesting

by Paulo Rosa-Santos, Francisco Taveira-Pinto, Mario López and Claudio A. Rodríguez

J. Mar. Sci. Eng. 2022, 10(5), 633; https://doi.org/10.3390/jmse10050633 - 06 May 2022

Cited by 8 | Viewed by 1931

Abstract

The marine renewable energy (MRE) industry is being stimulated by the growing world energy demand, climate change mitigation policies, and land-use conflicts [...] Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

Research

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22 pages, 5817 KiB

Open AccessArticle

Assessing the Effectiveness of a Novel WEC Concept as a Co-Located Solution for Offshore Wind Farms

by Victor Ramos, Gianmaria Giannini, Tomás Calheiros-Cabral, Mario López, Paulo Rosa-Santos and Francisco Taveira-Pinto

J. Mar. Sci. Eng. 2022, 10(2), 267; https://doi.org/10.3390/jmse10020267 - 15 Feb 2022

Cited by 19 | Viewed by 2992

Abstract

The combined exploitation of wave and offshore wind energy resources is expected to improve the cost competitiveness of the wave energy industry as a result of shared capital and operational costs. In this context, the objective of this work is to explore the [...] Read more.

The combined exploitation of wave and offshore wind energy resources is expected to improve the cost competitiveness of the wave energy industry as a result of shared capital and operational costs. In this context, the objective of this work is to explore the potential benefits of co-locating CECO, an innovative wave energy converter, with the commercial WindFloat Atlantic wind farm, located on the northern coast of Portugal. For this purpose, the performance of the combined farm was assessed in terms of energy production, power smoothing and levelised cost of energy (LCoE). Overall, the co-located farm would increase the annual energy production by approximately 19% in comparison with the stand-alone wind farm. However, the benefits in terms of power output smoothing would be negligible due to the strong seasonal behaviour of the wave resource in the area of study. Finally, the LCoE of the co-located farm would be drastically reduced in comparison with the stand-alone wave farm, presenting a value of 0.115 per USD/kWh, which is similar to the levels of the offshore wind industry as of five years ago. Consequently, it becomes apparent that CECO could progress more rapidly towards commercialisation when combined with offshore wind farms. Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

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17 pages, 5556 KiB

Open AccessArticle

Hydraulic and Structural Assessment of a Rubble-Mound Breakwater with a Hybrid Wave Energy Converter

by Daniel Clemente, Tomás Calheiros-Cabral, Paulo Rosa-Santos and Francisco Taveira-Pinto

J. Mar. Sci. Eng. 2021, 9(9), 922; https://doi.org/10.3390/jmse9090922 - 25 Aug 2021

Cited by 9 | Viewed by 2884

Abstract

Seaports’ breakwaters serve as important infrastructures capable of sheltering ships, facilities, and harbour personnel from severe wave climate. Given their exposure to ocean waves and port authorities’ increasing awareness towards sustainability, it is important to develop and assess wave energy conversion technologies suitable [...] Read more.

Seaports’ breakwaters serve as important infrastructures capable of sheltering ships, facilities, and harbour personnel from severe wave climate. Given their exposure to ocean waves and port authorities’ increasing awareness towards sustainability, it is important to develop and assess wave energy conversion technologies suitable of being integrated into seaport breakwaters. To fulfil this goal whilst ensuring adequate sheltering conditions, this paper describes the performance and stability analysis of the armour layer and toe berm of a 1/50 geometric scale model of the north breakwater extension project, intended for the Port of Leixões, with an integrated hybrid wave energy converter. This novel hybrid concept combines an oscillating water column and an overtopping device. The breakwater was also studied without the hybrid wave energy device as to enable a thorough comparison between both solutions regarding structural stability, safety, and overtopping performance. The results point towards a considerable reduction in the overtopping volumes through the integration of the hybrid technology by an average value of 50%, while the stability analysis suggests that the toe berm of the breakwater is not significantly affected by the hybrid device, leading to acceptable safety levels. Even so, some block displacements were observed, and the attained stability numbers were slightly above the recommended thresholds from the literature. It is also shown that traditional damage assessment parameters should be applied with care when non-conventional structures are analysed, such as rubble-mound breakwaters with integrated wave energy converters. Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

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19 pages, 9797 KiB

Open AccessArticle

Flume Experiments on Energy Conversion Behavior for Oscillating Buoy Devices Interacting with Different Wave Types

by Shufang Qin, Jun Fan, Haiming Zhang, Junwei Su and Yi Wang

J. Mar. Sci. Eng. 2021, 9(8), 852; https://doi.org/10.3390/jmse9080852 - 08 Aug 2021

Cited by 6 | Viewed by 2479

Abstract

Oscillating buoy device, also known as point absorber, is an important wave energy converter (WEC) for wave energy development and utilization. The previous work primarily focused on the optimization of mechanical design, buoy’s array configuration and the site selection with larger wave energy [...] Read more.

Oscillating buoy device, also known as point absorber, is an important wave energy converter (WEC) for wave energy development and utilization. The previous work primarily focused on the optimization of mechanical design, buoy’s array configuration and the site selection with larger wave energy density in order to improve the wave energy generation performance. In this work, enlightened by the potential availability of Bragg reflection induced by multiple submerged breakwaters in nearshore areas, we investigate the energy conversion behavior of oscillating buoy devices under different wave types (traveling waves, partial and fully standing waves) by flume experiments. The localized partial standing wave field is generated by the Bragg resonance at the incident side of rippled bottoms. Furthermore, the fully standing wave field is generated by the wave reflection of vertical baffle installed in flume. Then the wave power generation performance is discussed under the conditions with the same wave height but different wave types. The experimental measurements show that the energy conversion performance of the oscillating buoy WEC could be improved under the condition of standing waves when compared with traveling waves. This work provides the experimental comparison evidence of wave energy conversion response of oscillating buoy devices between travelling waves and standing (fully or partial) wave conditions. Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

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27 pages, 14096 KiB

Open AccessArticle

Proof of Concept of a Breakwater-Integrated Hybrid Wave Energy Converter Using a Composite Modelling Approach

by Theofano I. Koutrouveli, Enrico Di Lauro, Luciana das Neves, Tomás Calheiros-Cabral, Paulo Rosa-Santos and Francisco Taveira-Pinto

J. Mar. Sci. Eng. 2021, 9(2), 226; https://doi.org/10.3390/jmse9020226 - 20 Feb 2021

Cited by 13 | Viewed by 4076

Abstract

Despite the efforts of developers, investors and scientific community, the successful development of a competitive wave energy industry is proving elusive. One of the most important barriers against wave energy conversion is the efficiency of the devices compared with all the associated costs [...] Read more.

Despite the efforts of developers, investors and scientific community, the successful development of a competitive wave energy industry is proving elusive. One of the most important barriers against wave energy conversion is the efficiency of the devices compared with all the associated costs over the lifetime of an electricity generating plant, which translates into a very high Levelised Cost of Energy (LCoE) compared to that of other renewable energy technologies such as wind or solar photovoltaic. Furthermore, the industrial roll-out of Wave Energy Converter (WEC) devices is severely hampered by problems related to their reliability and operability, particularly in open waters and during harsh environmental sea conditions. WEC technologies in multi-purpose breakwaters—i.e., a structure that retains its primary function of providing sheltered conditions for port operations to develop and includes electricity production as an added co-benefit—appears to be a promising approach to improve cost-effectiveness in terms of energy production. This paper presents the proof of concept study of a novel hybrid-WEC (HWEC) that uses two well understood power generating technologies, air and water turbines, integrated in breakwaters, by means of a composite modelling approach. Preliminary results indicate: firstly, hybridisation is an adequate approach to harness the available energy most efficiently over a wide range of metocean conditions; secondly, the hydraulic performance of the breakwater improves; finally, no evident negative impacts in the overall structural stability specific to the integration were observed. Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

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21 pages, 10390 KiB

Open AccessFeature PaperArticle

Wave Energy Converter Power Take-Off System Scaling and Physical Modelling

by Gianmaria Giannini, Irina Temiz, Paulo Rosa-Santos, Zahra Shahroozi, Victor Ramos, Malin Göteman, Jens Engström, Sandy Day and Francisco Taveira-Pinto

J. Mar. Sci. Eng. 2020, 8(9), 632; https://doi.org/10.3390/jmse8090632 - 20 Aug 2020

Cited by 26 | Viewed by 4263

Abstract

Absorbing wave power from oceans for producing a usable form of energy represents an attractive challenge, which for the most part concerns the development and integration, in a wave energy device, of a reliable, efficient and cost-effective power take-off mechanism. During the various [...] Read more.

Absorbing wave power from oceans for producing a usable form of energy represents an attractive challenge, which for the most part concerns the development and integration, in a wave energy device, of a reliable, efficient and cost-effective power take-off mechanism. During the various stages of progress, for assessing a wave energy device, it is convenient to carry out experimental testing that, opportunely, takes into account the realistic behaviour of the power take-off mechanism at a small scale. To successfully replicate and assess the power take-off, good practices need to be implemented aiming to correctly scale and evaluate the power take-off mechanism and its behaviour. The present paper aims to explore and propose solutions that can be applied for reproducing and assessing the power take-off element during experimental studies, namely experimental set-ups enhancements, calibration practices, and error estimation methods. A series of recommendations on how to practically organize and carry out experiments were identified and three case studies are briefly covered. It was found that, despite specific options that can be strictly technology-dependent, various recommendations could be universally applicable. Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

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20 pages, 2566 KiB

Open AccessFeature PaperArticle

Combined Floating Offshore Wind and Solar PV

by Mario López, Noel Rodríguez and Gregorio Iglesias

J. Mar. Sci. Eng. 2020, 8(8), 576; https://doi.org/10.3390/jmse8080576 - 30 Jul 2020

Cited by 71 | Viewed by 10435

Abstract

To mitigate the effects of wind variability on power output, hybrid systems that combine offshore wind with other renewables are a promising option. In this work we explore the potential of combining offshore wind and solar power through a case study in Asturias [...] Read more.

To mitigate the effects of wind variability on power output, hybrid systems that combine offshore wind with other renewables are a promising option. In this work we explore the potential of combining offshore wind and solar power through a case study in Asturias (Spain)—a region where floating solutions are the only option for marine renewables due to the lack of shallow water areas, which renders bottom-fixed wind turbines inviable. Offshore wind and solar power resources and production are assessed based on high-resolution data and the technical specifications of commercial wind turbines and solar photovoltaic (PV) panels. Relative to a typical offshore wind farm, a combined offshore wind–solar farm is found to increase the capacity and the energy production per unit surface area by factors of ten and seven, respectively. In this manner, the utilization of the marine space is optimized. Moreover, the power output is significantly smoother. To quantify this benefit, a novel Power Smoothing (PS) index is introduced in this work. The PS index achieved by combining floating offshore wind and solar PV is found to be of up to 63%. Beyond the interest of hybrid systems in the case study, the advantages of combining floating wind and solar PV are extensible to other regions where marine renewable energies are being considered. Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

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37 pages, 9714 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Theoretical Evaluation of the Hydrodynamic Characteristics of Arrays of Vertical Axisymmetric Floaters of Arbitrary Shape in front of a Vertical Breakwater

by Dimitrios N. Konispoliatis, Spyridon A. Mavrakos and Georgios M. Katsaounis

J. Mar. Sci. Eng. 2020, 8(1), 62; https://doi.org/10.3390/jmse8010062 - 20 Jan 2020

Cited by 22 | Viewed by 2966

Abstract

The present paper deals with the analytical evaluation of the hydrodynamic characteristics of an array of vertical axisymmetric bodies of arbitrary shape, placed in front of a reflecting vertical breakwater, which can be conceived as floaters for wave power absorption. At the first [...] Read more.

The present paper deals with the analytical evaluation of the hydrodynamic characteristics of an array of vertical axisymmetric bodies of arbitrary shape, placed in front of a reflecting vertical breakwater, which can be conceived as floaters for wave power absorption. At the first part of the paper, the hydrodynamic interactions between the floaters and the adjacent breakwater are exactly taken into account using the method of images, whereas, the interaction phenomena between the floaters of the array are estimated using the multiple scattering approach. For the solution of the problem, the flow field around each floater of the array is subdivided into ring-shaped fluid regions, in each of which axisymmetric eigenfunction expansions for the velocity potential are made. In the second part of the paper, extensive theoretical results are presented concerning the exciting wave forces and the hydrodynamic coefficients for various arrays’ arrangements of axisymmetric floaters. The aim of the study is to show parametrically the effect that the vertical breakwater has on the hydrodynamic characteristics of each particular floater. Full article

(This article belongs to the Special Issue Hybrid Systems for Marine Energy Harvesting)

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