What about Marine Renewable Energies in Spain?

Optimizing Wave Overtopping Energy Converters by ANN Modelling: Evaluating the Overtopping Rate Forecasting as the First Step

Artificial neural networks (ANN) are extremely powerful analytical, parallel processing elements that can successfully approximate any complex non-linear process, and which form a key piece in Artificial Intelligence models. Its field of application, being very wide, is especially suitable for the field of prediction. In this article, its application for the prediction of the overtopping rate is presented, as part of a strategy for the sustainable optimization of coastal or harbor defense structures and their conversion into Waves Energy Converters (WEC). This would allow, among others benefits, reducing their initial high capital expenditure. For the construction of the predictive model, classical multivariate statistical techniques such as Principal Component Analysis (PCA), or unsupervised clustering methods like Self Organized Maps (SOM), are used, demonstrating that this close alliance is always methodologically beneficial. The specific application carried out, based on the data provided by the CLASH and EurOtop 2018 databases, involves the creation of a useful application to predict overtopping rates in both sloping breakwaters and seawalls, with good results both in terms of prediction error, such as correlation of the estimated variable.

Offshore Wind Farms

In 2018, we were approached by the editorial team of the Journal of Marine Science and Engineering (MDPI editorial) to act as guest editors of a Special Issue related to offshore wind energy [...]

Foundations in Offshore Wind Farms: Evolution, Characteristics and Range of Use. Analysis of Main Dimensional Parameters in Monopile Foundations

Renewable energies are the future, and offshore wind is undoubtedly one of the renewable energy sources for the future. Foundations of offshore wind turbines are essential for its right development. There are several types: monopiles, gravity-based structures, jackets, tripods, floating support, etc., being the first ones that are most used up to now. This manuscript begins with a review of the offshore wind power installed around the world and the exposition of the different types of foundations in the industry. For that, a database has been created, and all the data are being processed to be exposed in clear graphic summarizing the current use of the different foundation types, considering mainly distance to the coast and water depth. Later, the paper includes an analysis of the evolution and parameters of the design of monopiles, including wind turbine and monopile characteristics. Some monomials are considered in this specific analysis and also the soil type. So, a general view of the current state of monopile foundations is achieved, based on a database with the offshore wind farms in operation.

Feasibility Study of the Installation of Wave Energy Converters in Existing Breakwaters in the North of Spain

In a context of growing global awareness of environmental sustainability, given the risks associated with global warming and climate change, the transition from environmental models to highly intensive fossil fuel production towards new clean energy systems marks the future of global public agendas. In this scenario, a feasibility study of the installation of wave energy converters, such as the Sea Slot-Cone Generator (SSG) and the Oscillating Water Column (OWC), was carried out in existing breakwaters in the North of Spain, choosing Punta Langosteira (Outer Port of A Coruña), Dique Torres and Dique Norte (Port el Musel, Gijón) and Punta Lucero (Port of Bilbao). It was aimed at capturing the great energy potential of the Atlantic Ocean, as an innovative solution linked to the development of renewable energy sources of marine origin. The selection of the most optimal and efficient alternative will depend on different aspects: the quantitative availability of the wave energy resource at the study points, the production of energy obtained by the device and the capacity factor, the capacity of the wave energy facility to supply the energy consumption in every port to boost the image of “Green Port”, the constructive viability so that the condition of having the construction works only during one year and an economic estimation of each alternative.

Study on Transient Overvoltage of Offshore Wind Farm Considering Different Electrical Characteristics of Vacuum Circuit Breaker

For the study of transient overvoltage (TOV) in an offshore wind farm (OWF) collector system caused by switching off vacuum circuit breakers (VCBs), a simplified experimental platform of OWF medium-voltage (MV) cable collector system was established in this paper to conduct switching operation tests of VCB and obtain the characteristic parameters for VCB, especially dielectric strength parameters; also, the effectiveness of the VCB reignition model was verified. Then, PSCAD/EMTDC was used to construct the MV collector system of the OWF, and the effects of normal switching and fault switching on TOV amplitude, steepness, and the total number of reignition of the VCB were studied, respectively, with the experimental parameters and traditional parameters of dielectric strength of the VCB. The simulation results show that when the VCB is at the tower bottom, the overvoltage amplitude generated by the normal switching is the largest, which is 1.83 p.u., and the overvoltage steepness of the fault switching is the largest, up to 142 kV/μs. The overvoltage amplitude and steepness caused by switching off VCB at the tower bottom faultily with traditional parameters are about 2 and 1.5 times of the experimental parameters under the same operating condition.