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La crisis causada por la COVID-19 ha despertado el miedo a olvidar la lucha contra el Cambio Climatico promoviendo varias iniciativas que exigen acelerar el Pacto Verde Europeo como via para salir de esta crisis. Las fuentes de energia renovable en el mar, incluyendo la eolica marina, la energia de las olas y las corrientes de marea, pueden desempenar un papel crucial en el cumplimiento de los objetivos de un sistema energetico bajo en carbono, uno de los seis ejes principales de la Recuperacion Verde, contribuyendo al mismo tiempo al crecimiento economico y la creacion de empleo. Sin embargo, se necesita una reduccion continua de costes para lograr tecnologias mas eficientes y competitivas. Las herramientas de diseno pueden ayudar a acelerar la reduccion de costes en las primeras etapas de desarrollo tecnologico o en la planificacion de proyectos. Este articulo muestra algunos ejemplos de herramientas de diseno desarrolladas en cuatro proyectos de I+D con financiacion europea: • DTOcean y DTOceanPlus proporcionan herramientas de diseno avanzadas para la innovacion, desarrollo e implementacion de sistemas de energia oceanica. • LIFES50 + aporta soluciones competitivas de subestructuras flotantes para aerogeneradores de 10 MW a profundidades superiores a 50 m. • OPERA recopila, analiza y comparte datos y experiencias operativas en mar abierto para validar y eliminar riesgos de varias innovaciones industriales para energia undimotriz. Las herramientas de diseno presentadas cubren diferentes etapas del desarrollo tecnologico o de proyectos: • Herramientas de modelizacion numerica multi-fisica para el diseno de aerogeneradores flotantes. • Herramientas para la toma de decisiones durante la fase de planificacion de parques renovables offshore. • Innovacion estructurada y validacion por fases para la evaluacion de innovaciones aplicables a renovables offshore en las primeras etapas de desarrollo. El lector podra encontrar referencias a utiles herramientas de codigo abierto y documentos publicos producidos por estos proyectos. Palabras clave: herramientas de diseno, eolica offshore, energia de las olas, corrientes de marea, modelado numerico, innovacion estructurada, planificacion de proyectos de despliegue

Demand for renewable energy is increasing steadily and regulated by national and international policies. Offshore wind energy sector has been clearly the fastest in its development among other options, and development of new wind farms requires large ocean space. Therefore, there is a need of efficient spatial planning process, including the site selection constrained by technical (wind resource, coastal distance, seafloor) and environmental (impacts) factors and competence of uses. We present a novel approach, using Bayesian Belief Networks (BBN), for an integrated spatially explicit site feasibility identification for offshore wind farms. Our objectives are to: (i) develop a spatially explicit model that integrates the technical, economic, environmental and social dimensions; (ii) operationalize the BBN model; (iii) implement the model at local (Basque Country) and regional (North East Atlantic and Western Mediterranean), and (iv) develop and analyse future scenarios for wind farm installation in a local case study. Results demonstrated a total of 1% (23 km(2)) of moderate feasibility areas in local scaled analysis, compared to 4% of (21,600 km(2)) very high, and 5% (30,000 km(2)) of high feasibility in larger scale analysis. The main challenges were data availability and discretization when trying to expand the model from local to regional level. The use of BBN models to determine the feasibility of offshore wind farm areas has been demonstrated adequate and possible, both at local and regional scales, allowing managers to take management decisions regarding marine spatial planning when including different activities, environmental problems and technological constraints. (C) 2019 Elsevier B.V. All rights reserved.

The floating offshore wind turbine (FOWT) market is currently dominated by single unit demonstration projects and first pre-commercial wind farms such as the Hywind Scotland wind farm. Today’s FOWT substructure design process is therefore not yet at a level of industrialization comparable to fixed-bottom substructure design methodologies, where standardized design and realization procedures are well established throughout the industry. Aligned with work performed in the Ramboll and University of Stuttgart-led work packages “Concept Industrialization” and “Design practice” of the European H2020 LIFES50+ project, the ambition of this paper is to define state-of-the-art fixed-bottom and floating design methods and based on these identify key differences through comparative analysis. In the first part of the paper the scope and selected details of today’s industrialized design process for fixed-bottom substructure design is presented, including e.g. load iteration schemes and applied numerical methods, risk assessment incorporation, optimization, and cost modelling. In the second part, the key elements of this industrialized procedure which are different to FOWT design are identified and described: This is done based on a review of the current FOWT common design practice, where elements are identified that are unique and/or different for FOWTs — this includes e.g. the requirement to adapt the controller to the specific platform behaviour, as well as a tower and/or selected rotor-nacelle assembly (RNA) component redesign, and also includes differences in terms of defining and performing load case simulations. Another observation that is described relates to the floating specific required numerical methodologies applied for the detailed structural and mooring design, where challenges exist regarding the interface between coupled global loads analyses tools and detailed structural, mooring, and geotechnical tools. A further key item discussed in this respect is the industry-common load exchange practice for fixed-bottom design, where only a limited data exchange between WT manufacturers and platform designers is done; a procedure that is challenging to be applied for FOWTs. Compared with fixed-bottom design, the consideration of manufacturability, fabrication constraints, serial production, design complexity reduction, assembly, supply chain, installation, geotechnics, O&M and risk is often limited and these items will also be briefly discussed. Overall the paper is intended as a technical review of existing fixed-bottom design procedures and, facilitated through the comparative analysis with these established design methodologies, identifies and presents the key differentiating design elements and challenges for an industrialized FOWT design. The content of the paper will provide input for the focused development of design processes for industrialized detailed design of FOWTs to guarantee the demanded technology-readiness and manufacturing-readiness levels (TRL and MRL) and ultimately improve their CAPEX and OPEX by applying industrial design procedures. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 640741 (LIFES50+ project, www.lifes50plus.eu).

Floating platforms for offshore wind tend to be very expensive and different solutions have been proposed to increase their cost-effectiveness. One of them involves the combination of offshore wind generation with other forms of ocean renewable energy, as is the subject of the FP7 project Marina Platform. In particular, wave energy from the sea has been investigated since the ’70s and although a few technologies have already reached a pre-commercial stage, their actual economic feasibility can still be questioned so that the possibility of sharing cables, moorings and even the structure with offshore wind turbine is very interesting also from the point of view of wave energy developers. This paper presents the design, modeling and analysis of a combined concept composed of a semi-submersible platform hosting a single 5 MW wind turbine and a heaving point-absorber consisting of a floating cylinder placed at the geometric center of the platform. A preliminary design of the concept is carried out by a frequency-domain analysis focused on the definition of the most suitable geometry with the objective of a limited dynamic response of the platform and satisfactory wave power absorption at the same time. It is shown how the requirement of maintaining reduced amplitude on the platform motions imposes the adoption of relatively slender cylinders as point-absorbers. After a conventional catenary mooring arrangement is assumed and its basic line parameters determined by applying a quasi-static approach, a global coupled time-domain model is built based on the Cummins equation and the use of panel codes (e.g. WAMIT, AQWA) for the computation of the hydrodynamic coefficients. Moorings are modeled as individual catenary lines whereas the dynamics of the wind turbine are modeled by introducing thrust and power curves as function of the motions of the platform, after previous determination with the Blade Element Momentum theory. The analysis is carried out over a set of operational sea states for different locations around Europe. Through the analysis of power performance, platform and point-absorber motions and mooring tensions, it is shown how the introduction of a Wave Energy Converter (WEC) can occasionally have a positive effect on the whole response of the platform though the significance of its energy contribution is relatively small and additional synergies have to be sought to justify its adoption.