The International Energy Agency Technology Collaboration Program for Ocean Energy Systems (OES) initiated the OES Wave Energy Conversion Modeling Task, which focused on the verification and validation of numerical models for simulating wave energy converters (WECs). The long-term goal is to assess the accuracy of and establish confidence in the use of numerical models used in design as well as power performance assessment of WECs. To establish this confidence, the authors used different existing computational modeling tools to simulate given tasks to identify uncertainties related to simulation methodologies: (i) linear potential flow methods; (ii) weakly nonlinear Froude–Krylov methods; and (iii) fully nonlinear methods (fully nonlinear potential flow and Navier–Stokes models). This article summarizes the code-to-code task and code-to-experiment task that have been performed so far in this project, with a focus on investigating the impact of different levels of nonlinearities in the numerical models. Two different WECs were studied and simulated. The first was a heaving semi-submerged sphere, where free-decay tests and both regular and irregular wave cases were investigated in a code-to-code comparison. The second case was a heaving float corresponding to a physical model tested in a wave tank. We considered radiation, diffraction, and regular wave cases and compared quantities, such as the WEC motion, power output and hydrodynamic loading.
Rigid fisheries management frameworks often leave fishermen with limited possibilities and incentives to adjust the selectivity of their gears to the specific fishing conditions. Implementation of the landing obligation in European fisheries emphasizes fishermen's need for flexibility in which gear to use to be able to match the selectivity of the gear to the quota available. How fishermen can play an important role in facilitating a more regionalised and flexible technical regulation by actively participating in the development of gears and contributing to the scientific documentation of their selectivity is discussed. Perspectives in the proposed technical regulation for EU fisheries and the regionalization in the 2013 Common Fisheries Policy are discussed based on an analysis of the current EU technical regulation. Then a new pathway to address the problem, currently being trialled in Danish fisheries, is discussed. Throughout the article, three themes are discussed: Identifying gear needs, development and testing of gear with fishermen as central actors; how the selectivity of the gear should be documented; and opportunities for faster evaluation of new gear, following the regionalization of the technical measure regulation. The paper concludes that a more flexible system of gear development and evaluation is possible by a) involvement of fishermen in proposing gear adjustments, self-sampling and documenting results following scientific protocols and evaluation, testing a range of designs before scientific testing, and b) open for faster approval of gear use under a regionalized technical regulation regime with annual adjustments of management plans containing the technical regulation.
The space occupied by traditional and new human-based marine uses at sea is expanding, creating a need for developing methods to assess interactions between co-located uses in maritime spatial planning (MSP). However, no clear terminology for use-use interactions exists. Thus, an analytical framework for spatial decision support tools (DSTs) to assess use-use interactions is deduced from literature. Four spatial-temporal links are found to either alone or together constitute use-use interactions: location links, environmental links, technical links, and user attraction links. It is found to be important for DSTs to support co-location management in MSP by iteratively through the MSP process 1) spatially-temporally locate spatial-temporal links constituting use-use interactions, 2) list conflicts and synergies of the located use-use interactions, and 3) weight the conflicts and synergies. With this analytical framework, two types of DSTs are analysed for their ability to include co-location; matrix- and ranking-based DSTs to detect conflicts and synergies and space allocating DSTs to avoid/minimise conflicts and optimise synergies. Whereas the first group of tools categorise or rank use-use combinations, the latter group use information about which multi-use combinations are possible as pre-existing knowledge, and thus the two groups of DSTs can advantageously be used together. A discrepancy is found between the co-location framework and the DSTs. It is argued that future tools could work on removing this discrepancy by considering the spatial-temporal links of use-use interactions, strengthen the focus on synergies, as well as prioritize ranking of synergies and conflicts over binary approaches that only evaluate spatial compatibility.
Green Liner Shipping Network Design refers to the problems in green logistics related to the design of maritime services in liner shipping with a focus on reducing the environmental impact. This chapter discusses how to more efficiently plan the vessel services with the use of mathematical optimization models. A brief introduction to the main characteristics of Liner Shipping Network Design is given, as well as the different variants and assumptions that can be considered when defining this problem. The chapter also includes an overview of the algorithms and approaches that have been presented in the literature to design such networks.
In order to enhance sustainability in maritime shipping, shipping companies spend good efforts in improving the operational energy efficiency of existing ships. Accurate fuel consumption prediction model is a prerequisite of such operational improvements. Existing grey-box models (GBMs) are found with significant performance potential for ship fuel consumption prediction, although having a limitation of separating weather directions. Aiming to overcome this limitation, we propose a novel genetic algorithm-based GBM (GA-based GBM), where ship fuel consumption is modelled in a procedure based on basic principles of ship propulsion and the unknown parameters in this model are estimated with a GA-based procedure. Real ship operation data from a crude oil tanker over a 7-year sailing period are used to demonstrate the accuracy and reliability of the proposed model. To highlight the contribution of this work, we compare the proposed model against the latest GBM. The results show that the fitting performance of the proposed model is remarkably better, especially for oblique weather directions. The proposed model can be employed as a basis of ship energy efficiency management programs to reduce fuel consumption and greenhouse gas (GHG) emissions of a ship. This is beneficial to achieve the goal of sustainable shipping.
The International Council for the Exploration of the Sea (ICES) occupies a central role in the advice system to support the implementation of an ecosystem approach to fisheries management (EAFM) in the European Union (EU). Despite improvements, its capacity to deliver ecosystem advice seems to be far from a fully functional operational framework. To what extent availability of appropriate scientific advice is a barrier for a more widespread use of an EAFM in Europe remains an open question. Building on the findings of a large research project, this article explores what advice ICES can provide. The article concludes that: (i) ICES has taken a leading role in generating an EAFM framework in which management decisions can operate; (ii) the advice “suppliers” and the advice “users” agree on the feasibility of using existing knowledge to “do EAFM now”; (iii) ICES can address a range of shortcomings, but some of the present bottlenecks demand concerted action between the advisory system and the political realm. The implementation of an EAFM requires consistency between science and management. ICES appears as well-suited to facilitate the dialogue on applying an EAFM in the EU, but it is unrealistic to expect ICES to produce all the answers.
Ports are crucial hubs in the functioning of the global economy, and maritime transport is a major emitter of air pollutants. Ports have considerable potential for promoting environmental upgrading in maritime transport and along global value chains more generally, but so far have been only partially successful in doing so. We examine results, limitations and future potential of voluntary initiatives that have been carried out by selected European and North American port authorities, which are considered frontrunners in environmental management. Drawing from the insights of global value chain analysis and organizational theory, we find that low ‘tool implementation complexity’ and high ‘issue visibility’ concerning emissions are key facilitators of environmental upgrading. We suggest that ports can intervene in two main ways to improve the environmental performance of maritime transport beyond their organizational and physical boundaries: by lowering tool implementation complexity through stronger collaboration within global value chains; and by enhancing emission visibility through alliances with cargo-owners and regulators.
The wave loads and the resulting motions of floating wave energy converters are traditionally computed using linear radiation–diffraction methods. Yet for certain cases such as survival conditions, phase control and wave energy converters operating in the resonance region, more complete mathematical models such as computational fluid dynamics are preferred and over the last 5 years, computational fluid dynamics has become more frequently used in the wave energy field. However, rigorous estimation of numerical errors, convergence rates and uncertainties associated with computational fluid dynamics simulations have largely been overlooked in the wave energy sector. In this article, we apply formal verification and validation techniques to computational fluid dynamics simulations of a passively controlled point absorber.
The phase control causes the motion response to be highly nonlinear even for almost linear incident waves. First, we show that the computational fluid dynamics simulations have acceptable agreement to experimental data. We then present a verification and validation study focusing on the solution verification covering spatial and temporal discretization, iterative and domain modelling errors. It is shown that the dominating source of errors is, as expected, the spatial discretization, but temporal and iterative errors cannot be neglected. Using hexahedral cells with low aspect ratio and 30 cells per wave height, we obtain results with less than 5% uncertainty in motion response (except for surge) and restraining forces for the buoy without phase control. The amplified nonlinear response due to phase control caused a large increase in numerical uncertainty, illustrating the difficulty to obtain reliable solutions for highly nonlinear responses, and that much denser meshes are required for such cases.
This paper examines if eco-rating schemes improve environmental outcomes in the context of the international shipping industry. Shipping faces global environmental challenges and has recently witnessed the introduction of several eco-rating schemes aiming to improve the environmental performance of ships. Extending the private environmental governance literature into a mature service industry with global operations, the paper shows that concerns about eco-rating schemes’ effectiveness also have relevance here. Shipping eco-rating schemes fall short of best practices for design and governance, and this hampers improvement efforts. The study has policy implications for the achievement of improved environmental outcomes in the shipping industry.
The use of the seas and oceans is generally regulated by the United Nations through the UN Convention on the Law of the Sea, which defines the rights and responsibilities. However, with the rapidly increasing use of the sea and oceans it is inevitable that conflicts may arise. Accordingly, there has been an increasing international recognition of the need to manage human activities that influence the marine environment and its ecosystems in an integrated, cross-sectoral manner. Recently, Maritime Spatial Planning (MSP) has gained significant attention as a new paradigm aiming at minimizing the conflicts among different sea uses through involving various stakeholders and sectors while aiming for sustainable growth. The aim of this research is to build a conceptual model for a Data Infrastructure to support marine space in a transnational context addressing the challenges related to the increasing use of marine areas and resources. The work was carried out in a close cooperation between several public authorities and research institutes in the Baltic Sea Region.