This paper proposes an optimisation strategy for the layout design of wave energy converter (WEC) arrays. Optimal layouts are sought so as to maximise the absorbed power given a minimum q-factor, the minimum distance between WECs, and an area of deployment. To guarantee an efficient optimisation, a four-parameter layout description is proposed. Three different optimisation algorithms are further compared in terms of performance and computational cost. These are the covariance matrix adaptation evolution strategy (CMA), a genetic algorithm (GA) and the glowworm swarm optimisation (GSO) algorithm. The results show slightly higher performances for the latter two algorithms; however, the first turns out to be significantly less computationally demanding.

Among the various types of wave energy converters currently being developed, heaving point absorbers are one of the simplest and most promising concepts. A typical efficient energy conversion system for point absorbers is based on hydraulic power take-off (PTO) systems, consisting in a double-acting cylinder, a hydraulic motor and two or more accumulators. This paper presents a simple model of a heaving oscillating buoy extracting power by means of a hydraulic system. The hydrodynamic behaviour of the absorber is modelled through application of the linear water wave theory. Apart from the basic elements listed above, the model of the hydraulic system includes leakages and pressure losses and takes into account the compressibility of the fluid. Also, possible control accumulators are considered in order to improve the performance of the hydraulic system by means of properly controlled valves. Different control variables are analysed depending on the wave inputs considered in order to improve the power extraction of the converter. The results prove that it is possible to achieve a great enhancement of the power extraction with the implementation of these control strategies and that a possible combination of some of them might be beneficial for improved efficiency of the components.

Recently, considerable interest has been generated in the wave energy production. As a new use of the ocean, a Spatial Planning approach is proposed to provide a mechanism to achieve consensus among the sectors operating at present, together with the identification of the most suitable locations to accommodate the Wave Energy Converters (WECs), in the near future. In this contribution: (a) a methodology for the establishment of a Suitability Index (SI) for WECs installation location selection is proposed; (b) the spatial distribution of the SI is mapped; and finally, (c) the accessible wave energy potential has been calculated for the entire Basque continental shelf. As the SI represents the appropriateness of several locations for WECs installation, while minimizing the conflict with other marine uses, the first step in the development of the analysis involved gathering all such information that may be likely to determine, or influence, the decision-making process. Seventeen information layers (among them 10 technical, 4 environmental, and 3 socioeconomical), corresponding to the identified key factors, including the theoretical wave energy in the study area, were generated to define their spatial distribution. Geographical Information System algorithms were used then in the assessment of the total theoretical energy potential and the accessible theoretical energy potential; these were calculated excluding areas where conflicts with other uses occur, such as navigation regulations or designated Marine Protected Areas. The resulting map indicates that, taking into account the zones not affected by “use conflicts,” together with the estimated energy performance of the most advanced WECs technology, the potential energy produced in the study area could supply between 37% and 50% of the electrical consumption of households in the Basque Country. This contribution could avoid the annual emission of 0.96 to 1.54 million tons of CO₂ into the atmosphere.

The history of underwater electrical connectors is relatively new: In 1858, the first transatlantic communication cable was created. Since then, the need for subsea electrical connectors has been growing very fast in the offshore industry. Today numerous companies offer a large choice of underwater connectors and assemblies, and it can be intricate to distinguish the different technologies employed for each of them. However the use, deployment, maintenance, and lifetime of any subsea equipment, from a simple sonar to a wave energy converter, relies on its connectors. Hence the design of an underwater electrical connector is to be carefully looked at, 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 the best 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.

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.