A novel methodology for the assessment or wave energy opions at early stages

276 p.El aumento de la proporción de generación de electricidad a partir de fuentes renovables es clave para garantizar un sistema energético totalmente descarbonizado y luchar contra el cambio climático. La energía undimotriz es un recurso abundante pero, al mismo tiempo, es la menos desarrollada de todas las tecnologías renovables. El marco de evaluación común desarrollado en la tesis se basa en principios sólidos de ingeniería de sistemas y abarca el contexto externo, los requisitos del sistema y los criterios de evaluación. Se puede aplicar a diferentes niveles de madurez tecnológica y capta los aspectos cualitativos relacionados con las expectativas de las partes interesadas. El enfoque novedoso guía las decisiones de diseño a lo largo del proceso de desarrollo para la gestión adecuada del riesgo y la incertidumbre, y facilita la selección y evaluación comparativa de la tecnología undimotriz a diferentes niveles de madurez de manera controlada. Los métodos propuestos en esta investigación brindan información valiosa para enfocar los esfuerzos de innovación en aquellas áreas que tienen la mayor influencia en el desempeño de la tecnología. La incorporación de estrategias de innovación eficaces en el desarrollo de la energía undimotriz ayuda a gestionar la complejidad del sistema y canalizar la innovación hacia mejoras útiles.Tecnali

Applying International Power Quality Standards for Current Harmonic Distortion to Wave Energy Converters and Verified Device Emulators

The push for carbon-free energy sources has helped encourage the development of the ocean renewable energy sector. As ocean renewable energy approaches commercial maturity, the industry must be able to prove it can provide clean electrical power of good quality for consumers. As part of the EU funded Open Sea Operating Experience to Reduce Wave Energy Cost (OPERA) project that is tasked with developing the wave energy sector, the International Electrotechnical Commission (IEC) developed electrical power quality standards for marine energy converters, which were applied to an oscillating water column (OWC). This was done both in the laboratory and in the real world. Precise electrical monitoring equipment was installed in the Mutriku Wave Power Plant in Spain and to an OWC emulator in the Lir National Ocean Test Facility at University College Cork in Ireland to monitor the electrical power of both. The electrical power generated was analysed for harmonic current distortion and the results were compared. The observations from sea trials and laboratory trials demonstrate that laboratory emulators can be used in early stage development to identify the harmonic characteristics of a wave energy converter.This research has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 654444 (OPERA project

An international perspective on marine renewable energy

Peer Reviewe

Technology-Agnostic Assessment of Wave Energy System Capabilities

Developing new wave energy technologies is risky, costly and time-consuming. The large diversity of concepts, components and evaluation criteria creates a vast design space of potentially feasible solutions. This paper aims to introduce a novel methodology for the holistic assessment of wave energy capabilities in various market applications based on sound Systems Engineering methods. The methodology provides a consistent hierarchy of performance metrics relevant to the given system of reference, design activity and development stage under consideration as a means to scrutinise wave energy requirements. Full traceability of system requirements and performance metrics is then facilitated by multi-criteria decision tools and aggregation logic, respectively. The qualitative assessment in the case studies has resulted in very different rankings of System Drivers and Stakeholders for the two market applications considered. However, the Stakeholder Requirements and Functional Requirements present a small variation in the weights for the two application markets which results in a quantitative assessment with very similar Global Merit. Finally, the performance benchmark using the Commercial Attractiveness and Technical Achievability concepts enables a more objective comparison in the utility-scale and remote generation markets and a way to concentrate innovation efforts before proceeding to the next development stage.This research received no external fundin

Review of Systems Engineering (SE) Methods and Their Application to Wave Energy Technology Development

The design of effective and economically viable wave energy devices involves complex decision-making about the product based on conceptual design information, including stakeholder requirements, functions, components and technical parameters. The great diversity of concepts makes it extremely difficult to create fair comparisons of the relative merits of the many different designs. Conventional design approaches have proved insufficient to guarantee wave energy technologies meet their technical and economic goals. Systems engineering can provide a suitable framework to overcome the obstacles towards a successful wave energy technology. The main objective of this work is to review the well-established systems engineering approaches that have been successfully implemented in complex engineering problems and to what extent they have been applied to wave energy technology development. The paper first reviews how system information can be organised in different design domains to guide the synthesis and analysis activities and the definition of requirements and metrics, as well as the search for solutions and decision-making. Then, an exhaustive literature review on the application of systems engineering approaches to wave energy development is presented per design domain. Finally, a set of conclusions is drawn, along with some suggestions for improving the effectiveness of wave energy technology development.Authors would like to thank the Basque Government through the research groups IT1314‐19 and GIU19/276 and the Scottish Government for the support of Wave Energy Scotland

O&M Models for Ocean Energy Converters: Calibrating through Real Sea Data

Of the cost centres that combine to result in Levelised Cost of Energy (LCOE), O&M costs play a significant part. Several developers have calculated component costs, demonstrating how they can become commercially competitive with other forms of renewable energy. However, there are uncertainties relating to the O&M figures that can only be reduced through lessons learned at sea. This work presents an O&M model calibrated with data from real sea experience of a wave energy device deployed at the Biscay Marine energy Platform (BiMEP): the OPERA O&M Model. Two additional case studies, utilising two other O&M calculation methodologies, are presented for comparison with the OPERA O&M Model. The second case study assumes the inexistence of an O&M model, utilising a Simplified Approach. The third case study applies DTOcean’s (a design tool for ocean energy arrays) O&M module. The results illustrate the potential advantages of utilising real sea data for the calibration and development of an O&M model. The Simplified Approach was observed to overestimate LCOE when compared to the OPERA O&M Model. This work also shows that O&M models can be used for the definition of optimal maintenance plans to assist with OPEX reduction.The authors are grateful to the European commission for funding the OPERA and EnFAIT projects as part of the Horizon 2020 framework. The authors also thankful to Oceantec-Idom for providing feedback to OPERA model’s inputs. A special thanks to Shona Pennock and Donald Noble for their diligent proofreading of this paper

Estimating Future Costs of Emerging Wave Energy Technologies

The development of new renewable energy technologies is generally perceived as a critical factor in the fight against climate change. However, significant difficulties arise when estimating the future performance and costs of nascent technologies such as wave energy. Robust methods to estimate the commercial costs that emerging technologies may reach in the future are needed to inform decision-making. The aim of this paper is to increase the clarity, consistency, and utility of future cost estimates for emerging wave energy technologies. It proposes a novel three-step method: (1) using a combination of existing bottom-up and top-down approaches to derive the current cost breakdown; (2) assigning uncertainty ranges, depending on the estimation reliability then used, to derive the first-of-a-kind cost of the commercial technology; and (3) applying component-based learning rates to produce the LCOE of a mature technology using the upper bound from (2) to account for optimism bias. This novel method counters the human propensity toward over-optimism. Compared with state-of-the-art direct estimation approaches, it provides a tool that can be used to explore uncertainties and focus attention on the accuracy of cost estimates and potential learning from the early stage of technology development. Moreover, this approach delivers useful information to identify remaining technology challenges, concentrate innovation efforts, and collect evidence through testing activities

Reducing variability in the cost of energy of ocean energy arrays

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 Laboratorie

Electrical Connectors for Underwater Application

Nowadays, numerous companies offer a large choice of underwater connectors and assemblies, and it can be complex to distinguish the different technologies employed for each of them. This chapter provides an overview of the types of connectors that exist for underwater and subsea electrical connections. It presents different types of commercial‐off‐the‐shelf electrical connectors, and lists their performances and defaults, as well as typical failure modes and their known causes. Although each manufacturer has its own designs and technologies, underwater connectors can be grouped into five main categories: rubber‐molded, rigid‐shell or bulkhead assemblies, fluid‐filled underwater mateable, inductive coupling, and assemblies (non‐unmateable). The chapter contains the theory on sealing and on connectors’ thermal, electrical, and mechanical properties. It provides information on connection procedures and other details about connecting subsea cables with a focus on the connection of offshore renewable energy farms.The research leading to these results is part of the OceaNET project, which has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 607656

Review of Electrical Connectors for Underwater Applications

The history of underwater electrical connectors is relativelynew: In 1858, the first transatlantic communication cable was created. Sincethen, the need for subsea electrical connectors has been growing very fastin the offshore industry. Today numerous companies offer a large choiceof underwater connectors and assemblies, and it can be intricate to distinguish the different technologies employed for each of them. However theuse, deployment, maintenance, and lifetime of any subsea equipment, froma simple sonar to a wave energy converter, relies on its connectors. Hencethe design of an underwater electrical connector is to be carefully lookedat, and especially for tailor-made applications that have more specific requirements. To produce a good connector, it is necessary to account for thermal, electrical, and mechanical properties, as well as to determine thebest materials that should be used for the application. Finally, connector issues go hand in hand with the deployment and operation of any electrical equipment, and it is of interest to review the different techniques for cable connection, as well as the challenges related to cable layout. Those challenges can be of different nature, but they should all be taken into account for any subsea connection