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The floods that struck lower Tagus valley in February 1979 correspond to the most intense floods in this river and affected the largest number of people in a river flow event in Portugal, during the last 150 years. In fact, the vast area affected impacted significantly circa 10k people in the lower Tagus sector (and an additional 7k in other regions of Portugal), including thousands of people evacuated or made homeless. In this context, the present study focuses on an in depth analysis of this event from a hydrodynamic perspective by means of Iber+ numerical model and on developing strategies to mitigate the flood episodes that occur in the lower section of the Tagus river using the outstating floods of February 1979 as benchmark. In this sense, several large dams and reservoirs are located along the Tagus river basin, and for that, dam operating strategies were developed and analyzed to take advantage of these infrastructures to minimize the effect of floods. Overall, the numerical results indicate a good agreement with water marks and some descriptions of the 1979 flood event, which demonstrates the model capability to evaluate floods in the area under study. Regarding flood mitigation, obtained results indicate that the frequency of floods can be reduced with the proposed strategies. In addition, hydraulic simulations corroborated an important decrease in water depth and velocity for the most extreme flood events, and also a certain reduction of flood extension was detected. This confirms the effectiveness of the proposed strategies to help in reducing flood impact in lower Tagus valley through the efficient functioning of dams.

Chinese offshore wind energy sector is experiencing a rapid growth. It is expected that China will become the world leader in terms of installed offshore wind energy capacity in the upcoming years. A multi-model ensemble of eight simulations from CORDEX project was considered to evaluate future offshore wind energy projections along the Chinese coast under the RCP8.5 warming scenario. Furthermore, offshore wind energy resource was classified attending to the richness of the resource, stability of the resource, risk and economic factors. The reliability of the CORDEX multi-model ensemble was analyzed by comparing CORDEX wind speed with two different datasets: in-situ data from oceanic buoys and ERA5 database. A general wind power density decrease was observed for the near future and the far future. At seasonal scale, differences were found depending on the season. Thus, a clear reduction was projected during spring, whilst increases were observed in wide areas during winter or autumn. Regarding the classification of the future offshore wind energy resource for the upcoming decades, most of the Chinese coastal area was defined as good or excellent due to its high offshore wind energy richness that compensate the low values on stability of the resource and risk factor.

VisualSPHysics, an open-source tool for creating realistic visualizations of smoothed particle hydrodynamics (SPH) simulations, is presented here. The proposed approach is used to import SPH simulations (from DualSPHysics code) into 3D graphics software (Blender) and supports a wide range of visual effects (realistic lighting and materials, texturing, motion blur and foam simulation). The tool features a graphical user interface that integrates into Blender for easier use. VisualSPHysics was conceived to bring advanced visual effects to scientific and engineering simulations, helping researchers to disseminate their projects.

Número especial: Advances in machine learning for natural hazards risk assessment [Abstract:] Reservoirs play a key role in many human societies due to their capability to manage water resources. In addition to their role in water supply and hydropower production, their ability to retain water and control the flow makes them a valuable asset for flood mitigation. This is a key function, since extreme events have increased in the last few decades as a result of climate change, and therefore, the application of mechanisms capable of mitigating flood damage will be key in the coming decades. Having a good estimation of the outflow of a reservoir can be an advantage for water management or early warning systems. When historical data are available, data-driven models have been proven a useful tool for different hydrological applications. In this sense, this study analyzes the efficiency of different machine learning techniques to predict reservoir outflow, namely multivariate linear regression (MLR) and three artificial neural networks: multilayer perceptron (MLP), nonlinear autoregressive exogenous (NARX) and long short-term memory (LSTM). These techniques were applied to forecast the outflow of eight water reservoirs of different characteristics located in the Miño River (northwest of Spain). In general, the results obtained showed that the proposed models provided a good estimation of the outflow of the reservoirs, improving the results obtained with classical approaches such as to consider reservoir outflow equal to that of the previous day. Among the different machine learning techniques analyzed, the NARX approach was the option that provided the best estimations on average. FEDER; 0034_RISC_ML_6_E Xunta de Galicia; ED431C 2021/44 Xunta de Galicia; ED481B-2021-108 Universidade de Vigo; 0000 131H TAL 641

The expansion of marine renewable power is a major alternative for the reduction of greenhouse gases emissions. In Europe, however, the high penetration of offshore wind brings intermittency and power variability into the existing power grid. Offshore solar photovoltaic power is another technological alternative under consideration in the plans for decarbonization. However, future variations in wind, air temperature or solar radiation due to climate change will have a great impact on both renewable energy resources. In this context, this study focusses on the offshore energy assessment off the coast of Western Iberia, a European region encompassing Portugal and the Northwestern part of Spain. Making use of a vast source of data from 35 simulations of a research project called CORDEX, this study investigates the complementarity of offshore wind and solar energy sources with the aim of improving the energy supply stability of this region up to 2040. The most pessimistic greenhouse gases emission scenario (RCP8.5) is considered. The 35 simulations are validated by comparing wind speed at 10m, air temperature at 2m and solar radiation values with data from the ERA5 reanalysis database. Although the offshore wind energy resource has proven to be higher than solar photovoltaic resource at annual scale, both renewable resources showed significant spatiotemporal energy variability throughout the western Iberian Peninsula. When both renewable resources are combined, the stability of the energy resource increased considerably throughout the year. The proposed wind and solar combination scheme is assessed by a performance classification method called Delphi, considering stability, resource, risk, and economic factors. The total index classification increases when resource stability is improved by considering hybrid offshore wind-photovoltaic solar energy production, especially along the nearshore waters.

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract:] Modelling hydrological processes with fully distributed models based on the shallow water equations implies a high computational cost, which often limits the resolution of the computational mesh. Therefore, in practice, modellers need to find a compromise between spatial resolution, numerical accuracy and computational cost. Moreover, this balance is probably related to the accuracy and resolution of the underlying Digital Terrain Model (DTM). In this work, it is studied the effect of the DTM resolution and the size of the computational mesh on the results and on the runtime of a hydrological model based on the 2D shallow water equations. Seven rainfall events in four different basins have been modelled using 3 DTMs and 3 different mesh resolutions. The results obtained highlight the relevance of the vertical accuracy versus the horizontal resolution of the DTMs. Furthermore, it has been observed that mesh resolutions greater than 25 m, together with LiDAR-based DTMs with horizontal resolution greater than 25 m, provide comparable outflow hydrographs. Xunta de Galicia; ED481B-2021-108 Xunta de Galicia; ED431C 2021/44 Xunta de Galicia; ED431C 2018/56 Fondo Europeo de Desarrollo Regional (FEDER); 0034_RISC_ML_6_E

[Abstract:] River floods, which are one of the most dangerous natural hazards worldwide, have increased in intensity and frequency in recent decades as a result of climate change, and the future scenario is expected to be even worse. Therefore, their knowledge, predictability, and mitigation represent a key challenge for the scientific community in the coming decades, especially in those local areas that are most vulnerable to these extreme events. In this sense, a multiscale analysis is essential to obtain detailed maps of the future evolution of floods. In the multiscale analysis, the historical and future precipitation data from the CORDEX (Coordinated Regional Downscaling Experiment) project are used as input in a hydrological model (HEC-HMS) which, in turn, feeds a 2D hydraulic model (Iber+). This integration allows knowing the projected future changes in the flow pattern of the river, as well as analyzing the impact of floods in vulnerable areas through the flood hazard maps obtained with hydraulic simulations. The multiscale analysis is applied to the case of the Miño-Sil basin (NW Spain), specifically to the city of Ourense. The results show a delay in the flood season and an increase in the frequency and intensity of extreme river flows in the Miño-Sil basin, which will cause more situations of flooding in many areas frequented by pedestrians and in important infrastructure of the city of Ourense. In addition, an increase in water depths associated with future floods was also detected, confirming the trend for future floods to be not only more frequent but also more intense. Detailed maps of the future evolution of floods also provide key information to decision-makers to take effective measures in advance in those areas most vulnerable to flooding in the coming decades. Although the methodology presented is applied to a particular area, its strength lies in the fact that its implementation in other basins and cities is simple, also taking into account that all the models used are freely accessible. Xunta de Galicia; ED431C 2021/44 FEDER; 0034_RISC_ML_6_E Xunta de Galicia; ED481B-2021-108

The DualSPHysics model is used to reproduce the physical model tests carried out in the large-scale wave flume at CEDEX, in Madrid (Spain), focused on wave overtopping of vertical coastal structure. This work presents the first attempt to apply Smoothed Particle Hydrodynamics (SPH) models to simulate long duration events (670 waves, corresponding to 25min time simulation) where the cumulative overtopping volume is measured with waves interacting against a vertical wall, that represents a typical defence designed for harbours and marinas in the Mediterranean Sea. A sensitivity analysis on some model parameters, the initial inter-particle distance, the smoothing length and the piston transfer function (by means of a gain factor), has been carried out for model validation. The two first parameters are related to the numerical resolution and the particle interaction distance in SPH, respectively. The gain factor is applied to amplify the magnitude of the piston displacement in order to compensate the wave decay, dependent on the wave steepness. A good agreement between the experimental and numerical cumulative overtopping volume and relative overtopping rate is achieved with errors lower than 1%. Once the model is validated and calibrated, it has been applied to different wave time series with the same energy spectrum in order to investigate the sensitivity of the overtopping response to different wave grouping, obtaining acceptable agreement with the forecasts provided by the European Overtopping manual.

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Climate change is causing the global sea surface temperature (SST) to rise. However, warming rates are lower in coastal areas affected by the upwelling that buffers the SST warming. The influence of the Canary upwelling system on coastal SST throughout the 21st century was analyzed taking advantage of the high spatial resolution of the Global Climate Models (GCMs) from the CMIP6 project to capture upwelling features. Future SST changes were evaluated both on the coast and in their oceanic counterparts under the 5–8.5 socioeconomic pathway scenario. Results showed a latitudinal displacement of the upwelling system to the north by the end of the century. Middle and north latitudes showed a strengthening in the buffering effect of upwelling with a greater influence on the differences between coast and ocean. Oppositely, the southernmost latitudes showed a weakening causing a homogenization of the SST between coast and ocean. Xunta de Galicia | Ref. ED431C 2017/64

The present study analyses changes in the timing and duration of the hot days season over the Middle East and North Africa region from 1970 to 2099 using model simulations of 11 regional models from the Coordinated Regional Climate Downscaling Experiment under the RCP8.5 scenario. In general, a non-symmetrical lengthening of the hot days season is projected, with a tendency to extend more into spring than into autumn. By the end of the century and the RCP8.5 scenario, Western Africa and the Persian Gulf display a hot days season starting 60¿days earlier than in the historical period (1970¿1999) (May vs. July, respectively). Southernmost latitudes are the most affected by a later retreat of the hot days season, of up to 60¿days with respect to the historical period (October vs. August). The length of the extreme season is projected to increase between 100 and 120¿days for the southernmost latitudes and the Persian Gulf resulting in nearly four more months with hot days conditions., This work was partially supported by the European Regional Development Fund (FEDER) under the project “Prevención de Riesgos de Inundaciones y Sequías en la Cuenca Internacional del Miño-Limia” Interreg-Poctep 2014–2020 (EU. INTERREG-POCTEP 2014-2020, 0034-RISC_ML_6_E) and by Xunta de Galicia under the project ED431C 2017/64-GRC (Grupos de Referencia Competitiva).

In those countries where wind plays a major role in the energy mix (EU, China and USA) actions have been carried out to develop offshore wind energy, albeit to varying degrees. These actions range from studying offshore wind to the development of laws and planning related to the construction of wind farms. Europe currently leads the way in offshore wind energy (with 84% of global installations), having achieved technical and commercial maturity, including the first floating wind farm to generate electricity, together with an emerging zero-subsidy culture. The Chinese wind industry has seen rapid development since 2005, however, well established laws, the use of a one-stop-shop system in the licencing process, and the establishment of higher feed-in tariffs (FITs), could all boost the Chinese offshore wind industry further. The possible future role of the USA in the offshore wind industry is now in the hands of its decision makers. A more streamlined licencing process, together with a long-term vision enshrined within stable economic incentives, could help to boost the offshore wind industry in the USA.

River plumes formed in the Cantabrian coast of the Bay of Biscay constitute the main source of nutrients for this coastal area. They are able to sustain high levels of phytoplankton and primary productivity which, in turn, affect the associated ecosystems. Moreover, these plumes also influence other processes as stratification, flow circulation, transport of pollutants or erosion-sedimentation patterns, affecting the morphodynamical and biogeochemical characteristics of the area, which makes their study of high importance. The general small extension of these plumes makes necessary the use of high spatial and temporal resolution data to characterize their fine-spatial structure and to identify their evolution that happens at a short time scale. For that, the response of the Cantabrian plumes to the main forcing was analyzed by means of data provided by the Moderate Resolution Imaging Spectroradiometer sensor onboard Aqua and Terra satellites, which provides daily high resolution of up to 250 m. Composite images of Nalon, Pas-Besaya, Nervion and Adour plumes were created to analyze the effect of each forcing, including river discharge, wind and tides. Adour is the only Cantabrian plume formed even under low discharges due to the greater basin and river discharge. The rest of Cantabrian plumes are only well developed under high river discharges, which shows this forcing as the most important. Nalon, Pas-Besaya and Nervion plumes mainly influence eastward locations whereas Adour plume mainly affects areas located north of river mouth, due to the predominant currents in each area. Wind has a remarkable impact when plumes are well developed, being especially important in Nalon, Pas-Besaya and Nervion plumes. Plume material is dispersed to the ocean (under upwelling and seaward winds) or retained near coast (under downwelling and landward winds) attending to the main wind direction, conditioning the characteristics of the plume area. The semidiurnal tidal cycle is also important when plumes are developed, being all of them greater under low tidal conditions, although the impact is less important in the Adour plume. The higher stability of Adour plume to the forcing could be related to the much greater extension, which makes necessary stronger forcing to cause similar effects. On the other hand, this greater extension favors its impact on thermohaline properties of seawater. The Adour River is able to provoke winter stratification in the plume area, as well as thermal inversions, which condition the thermohaline properties respect to oceanic area not affected by the plume. By last, the influence of Cantabrian plumes on the annual cycle of chlorophyll was evaluated for each plume area and the adjacent ocean also by means of MODIS data. A chlorophyll peak was detected in both areas for early spring and high values of chlorophyll were also detected during autumn and winter but only in plume areas, associated to the input of nutrients and the haline stratification promoted by the high rivers discharges during these months.

The themed issue on “Sustainable resource management: water practice issues” includes a wide variety of original contributions in environmental hydrology, hydrogeology, thermal waters, mining hydrogeology, urban groundwater, hydrologic engineering, and water-related research and practice. This contribution summarises the scope of a selection of the studies presented mainly during the sessions on “general research on water” from the 1st and 2nd International Congress on Water Healing Spa and Life Quality—“I and II Symposium Internacional de Termalismo y Calidad de Vida” (STCV)—, that took place in Ourense (Galicia, Spain) in 2015 and 2017. The special issue presents key studies and model regions in hydrology, groundwater and thermal water processes, exploration, abstraction, protection, and sustainable management of the water resources. The articles also contribute to the overall knowledge of hydrological systems under a climate variability framework and societal pressures. In addition, the importance of an ethos of long-term environmental sustainability, socio- and eco-responsibility, and ethics in water resource management is highlighted.

Minho River intrusion into the Rias Baixas has a twofold impact on estuaries. On the one hand, freshwater intrusion can modify the water exchange with the shelf affecting the residence time. On the other hand, it can fertilize the area and promote phytoplankton blooms and increase estuarine primary production. For these reasons, it is crucial to understand the frequency, duration, and relaxation of river freshwater intrusions. The frequency of intrusion events into the rias was calculated by means of in situ data from 2006 to 2016 using the difference in salinity between the inner part of the estuary and the southern mouth (ΔS) as a proxy. Minho River intrusions, which are characterized by ΔS > 0, were detected in 8.9% of the available measurements in the Ria de Vigo, in 8.4% in the Ria de Pontevedra, and in only 4.5% in the Ria de Arousa. The FLOW module of the Delft3D model, which was previously calibrated and validated for the study area, was used to analyze the hydrodynamics of the intrusion events. The Ria de Vigo, which is the closest one to the Minho Estuary, was chosen to analyze the duration and intensity of the freshwater intrusions. Several consecutive events were detected in early 2010 (January 11th to February 8th) with ΔS values ranging from 0.7 to 2.0. Velocity and density profiles were analyzed in the middle part of the estuary, where seven freshwater intrusions matched the wind peaks favorable to intrusion events with an approximate delay of ~12 h. In general, the duration of the events was on the order of 1.5 days, although in one particular case the event lasted >3 days. The dynamic behavior of the freshwater intrusions was represented using velocity and density profiles along the main axis of Ria de Vigo. Finally, the phases of an intrusion event were characterized: initial positive estuarine circulation pattern; development of the intrusion; well-developed negative estuarine circulation; relaxation of the intrusion and recovery of the initial positive circulation.

Ports constitute a significant influence in the economic activity in coastal areas through operations and infrastructures to facilitate land and maritime transport of cargo. Ports are located in a multi-dimensional environment facing ocean and river hazards. Higher warming scenarios indicate Europe’s ports will be exposed to higher risk due to the increase in extreme sea levels (ESL), a combination of the mean sea level, tide, and storm surge. Located on the west Iberia Peninsula, the Aveiro Port is located in a coastal lagoon exposed to ocean and river flows, contributing to higher flood risk. This study aims to assess the flood extent for Aveiro Port for historical (1979–2005), near future (2026–2045), and far future (2081–2099) periods scenarios considering different return periods (10, 25, and 100-year) for the flood drivers, through numerical simulations of the ESL, wave regime, and riverine flows simultaneously. Spatial maps considering the flood extent and calculated area show that most of the port infrastructures’ resilience to flooding is found under the historical period, with some marginal floods. Under climate change impacts, the port flood extent gradually increases for higher return periods, where most of the terminals are at high risk of being flooded for the far-future period, whose contribution is primarily due to mean sea-level rise and storm surges. Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/114919/2016 Fundação para a Ciência e a Tecnologia | Ref. CEECIND/00459/2018 Fundação para a Ciência e a Tecnologia | Ref. UIDB/50017/2020 Fundação para a Ciência e a Tecnologi | Ref. UIDP/50017/2020 European Cooperation in Science and Technology (COST) | Ref. H2020, CA17105

Aquaculture is one of the fastest-growing activities worldwide. This strong and rapid development of the sector tends to be reflected in significant environmental impacts and new challenges in the management of the coastal areas. In this context, this work intends to contribute to the sustainability of the sector, by proposing an innovative method to identify preferred locations to ensure sustainable expansion of fish and mussels aquaculture, under optimal hydrodynamic and water quality conditions in Ria de Aveiro (Portugal) and Rias Baixas (Spain). A habitat model was developed, integrating hydrodynamic and water quality modelling results into a suitability index based on the definition of variable suitability functions. The results show that 22% of Ria de Aveiro is very good for fish production. In contrast, the production of pelagic fish in Rias Baixas is not recommended due to vertical gradients of water temperature and seasonal events of hypoxia. Concerning to mussels, the habitat model classifies 31% of Ria de Aveiro area as very good for production, while most of the Rias Baixas area presents this highest classification, confirming the high exploitation of the region. The definition of appropriate areas for aquaculture exploitation is highly related with the different geomorphological, hydrological and biogeochemical processes of Ria de Aveiro and Rias Baixas. Results for Ria de Aveiro indicate that the upstream areas are the most vulnerable from the water quality point of view, highlighting the importance of the advective processes in the lagoon's water quality, in opposition to Rias Baixas dynamics, where stratification is more relevant. In Rias Baixas, the strong vertical gradient of water temperature and dissolved oxygen prevents fish from having sustainable growth rates. Therefore, this work demonstrated the potential of the proposed method based on hydrodynamic and biogeochemical modelling to support the decision-making process in planning aquaculture expansion.

The present work addresses the need for an efficient, versatile, accurate and open-source numerical tool to be used during the design stage of wave energy converters (WECs). The device considered here is the heaving point-absorber developed and tested by Sandia National Laboratories. The smoothed particle hydrodynamics (SPH) method, as implemented in DualSPHysics, is proposed since its meshless approach presents some important advantages when simulating floating devices. The dynamics of the power take-off system are also modelled by coupling DualSPHysics with the multi-physics library Project Chrono. A satisfactory matching between experimental and numerical results is obtained for: (i) the heave response of the device when forced via its actuator; (ii) the vertical forces acting on the fixed device under regular waves and; (iii) the heave response of the WEC under the action of both regular waves and the actuator force. This proves the ability of the numerical approach proposed to simulate accurately the fluid–structure interaction along with the WEC’s closed-loop control system. In addition, radiation models built from the experimental and WAMIT results are compared with DualSPHysics by plotting the intrinsic impedance in the frequency domain, showing that the SPH method can be also employed for system identification. Xunta de Galicia | Ref. ED431C 2017/64 Ministerio de Economía y Competitividad | Ref. ENE2016-75074-C2-1-R European Commission

Dynamic boundary conditions (DBC) for solid surfaces are standard in the weakly compressible smoothed particle hydrodynamics (SPH) code DualSPHysics. A stationary solid is simply represented by fixed particles with pressure from the equation of state. Boundaries are easy to set up and computations are relatively stable and efficient, providing robust numerical simulation for complex geometries. However, a small unphysical gap between the fluid and solid boundaries can form, decreasing the accuracy of pressures measured on the boundary. A method is presented where the density of solid particles is obtained from ghost positions within the fluid domain by linear extrapolation. With this approach, the gap between fluid and boundary is reduced and pressures in still water converge to hydrostatic, including the case of a bed with a sharp corner. The violent free-surface cases of a sloshing tank and dam break impact on an obstacle show pressures measured directly on solid surfaces in close agreement with experiments. The complex 3-D flow in a fish pass, with baffles to divert the flow, is simulated showing close agreement with measured water levels with weirs open and gates closed, but less close with gates open and weirs closed. This indicates the method is suitable for rapidly varying free-surface flows, but development for complex turbulent flows is necessary. The code with the modified dynamic boundary condition (mDBC) is available in DualSPHysics to run on CPUs or GPUs. Engineering and Physical Sciences Research Council | Ref. EP/P510579/1 Xunta de Galicia | Ref. ED431C 2017/64 Ministerio de Economía y Competitividad | Ref. WELCOME ENE2016-75074-C2-1-R Ministerio de Ciencia, Innovación y Universidades | Ref. IJCI-2017-32592 Ministero dell’Istruzione, dell’Università e della Ricerca | Ref. RBSI14R1GP Mexican CONACYT-SENER Hidrocarburos | Ref. B-S-69926

The mortality of infaunal bivalves (Venerupis corrugata, Cerastoderma edule, Ruditapes decussatus and Ruditapes philippinarum) due to a drop in salinity caused by extreme precipitation events in estuarine areas has been analyzed within a context of climate change. The Rías Baixas (NW Iberian Peninsula) were selected as a representative area of the estuarine environments where bivalve gathering is performed. Bivalve mortality under extreme precipitation events was analyzed both for historical (1990–2019) and future (2070–2099) periods. Precipitation data were retrieved from the Coordinated Regional Climate Downscaling Experiment (CORDEX) project under the Representative Concentration Pathway (RCP) 8.5 scenario and were converted into river discharges using the HEC-HMS hydrological model. The calculated river discharges were introduced into the Delft3D hydrodynamic model and simulations were performed in order to calculate transport conditions in the Rías Baixas. Salinity data were analyzed to estimate the mortality of the species due to salinity drops. In general, future conditions of moderate and severe mortality may be worse than historically observed, being more intense and covering larger areas. This is mainly observed under neap tides due to less dilution of freshwater plumes when compared with spring tides. Although all the Rías Baixas may be potentially affected, the impact will differ for each ria, being Arousa, where the highest discharges occur, the most affected. The differences among rias, especially those with a similar discharge pattern as Pontevedra and Vigo, suggest that bathymetric features also play a key role in the extent of the area affected by mortality. Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Xunta de Galicia | Ref. ED431C 2017/64 Fundação para a Ciência e a Tecnologia | Ref. UIDP/50017/2020 Fundação para a Ciência e a Tecnologia | Ref. UIDB/50017/2020

Wind energy resources are subject to changes in climate, so the use of wind energy density projections in the near future is essential to determine the viability and profitability of wind farms at particular locations. Thus, a step forward in determining the economic assessment of floating offshore wind farms was taken by considering current and near-future wind energy resources in assessing the main parameters that determine the economic viability (net present value, internal rate of return, and levelized cost of energy) of wind farms. This study was carried out along the Atlantic coast from Brest to Cape St. Vincent. Results show that the future reduction in wind energy density (2%–6%) mainly affects the net present value (NPV) of the farm and has little influence on the levelized cost of energy (LCOE). This study provides a good estimate of the economic viability of OWFs (Offshore Wind Farms) by taking into account how wind resources can vary due to climate change over the lifetime of the farm This research was partially funded by Project PID2019-105386RA-I00 “Design of a tool for the selection of offshore renewable energy locations and technologies: application to Spanish territorial waters (SEARENEW)”, financed by Ministerio de Ciencia e Innovación—Agencia Estatal de Investigación/10.13039/501100011033. This work was partially financed by Xunta de Galicia (Spain) under project ED431C 2017/64 “Programa de Consolidacion e Estructuracion de Unidades de Investigacion Competitivas”. A. Ribeiro benefits from PhD Grants (SFRH/BD/114919/2016) given by the Portuguese Science Foundation FCT (Fundação para a Ciência e Tecnologia). Thanks are due to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020+UIDB/50017/2020), through national funds SI

Smoothed Particle Hydrodynamics (SPH) method is used here to simulate a heaving point-absorber with a Power Take-Off system (PTO). The SPH-based code DualSPHysics is first validated with experimental data of regular waves interacting with the point-absorber. Comparison between the numerical and experimental heave displacement and velocity of the device show a good agreement for a given regular wave condition and different configurations of the PTO system. The validated numerical tool is then employed to investigate the efficiency of the proposed system. The efficiency, which is defined here as the ratio between the power absorbed by the point-absorber and its theoretical maximum, is obtained for different wave conditions and several arrangements of the PTO. Finally, the effects of highly energetic sea states on the buoy are examined through alternative configurations of the initial system. A survivability study is performed by computing the horizontal and vertical forces exerted by focused waves on the wave energy converter (WEC). The yield criterion is used to determine that submerging the heaving buoy at a certain depth is the most effective strategy to reduce the loads acting on the WEC and its structure, while keeping the WEC floating at still water level is the worst-case scenario. This work was partially financed by the Ministry of Economy and Competitiveness of the Government of Spain under project “WELCOME ENE2016-75074-C2-1-R″ and financed by Xunta de Galicia (Spain) under project ED431C 2017/64 ″Programa de Consolidación e Estructuración de Unidades de Investigación Competitivas (Grupos de Referencia Competitiva)" cofunded by European Regional Development Fund (ERDF). Dr. C. Altomare acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.: 792370. Dr J. M. Domínguez acknowledges funding from Spanish government under the program “Juan de la Cierva-incorporación 2017” (IJCI-2017-32592).