Refined numerical wave energy resource assessments are required to reduce uncertainties in the evaluation of available power and energy production. However, to restrict the computational cost, a great part of wave hindcast simulations cover a limited time range (below ten years) or rely on coarse spatial resolutions while routinely ignoring tide-induced modulations in wave conditions. Complementing resource assessments conducted in the North-West European shelf seas, we here exploited a 27-year hindcast database (1994–2020) set up at a spatial resolution of 200 m along the coast of France and integrating the effects of tidal currents on waves. This evaluation was conducted in three water depths from offshore to nearshore (60, 40 and 20 m) around Brittany, one of the most energetic regions along the coast of France. We investigated the performances of a series of thirteen state-of-the-art wave energy converters with respect to installation depth range. Beyond confirming the interest of western Brittany in energy exploitation, the results exhibited the first ranking between devices, thus promoting the interests of Oceantec in offshore waters (60 m), Wave Dragon in intermediate waters (40 m), and Oyster and WaveStar C6 in shallow waters (20 m).@en

The wave energy resources in the Indian Ocean can be considered as a potential alternative to fossil fuels. However, the wave energy resources are subject to short-term fluctuations and long-term changes due to climate change. Hence, considering sustainable development goals, it is necessary to assess both short-term (intra-annual) variation and long-term change. For this purpose, the simulated wave characteristics were utilized, and the wave power and its variation and change were analyzed in the whole domain and nearshore areas. The short-term fluctuation was investigated in terms of monthly and seasonal variations and the future change was discussed based on absolute and relative changes. Both analyses show that the Southern Indian Ocean, despite experiencing extreme events and having higher wave energy potential, is more stable in terms of both short and long-term variation and change. The assessment of the total and exploitable storages of wave energy and their future change revealed the higher potential and higher stability of the nearshores of the Southern Indian Ocean. It can be concluded that based on various factors, the south of Sri Lanka, Horn of Africa, southeast Africa, south of Madagascar and Reunion and Mauritius islands are the most suitable areas for wave energy extraction.

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Global distribution of the wave climate and energy using a re-analysis dataset provides the opportunity to study spatio-temporal variation of different parameters, and offers inputs for future sustainability plans. The study assesses two global scale products ERA5 and ERA-Interim, evaluating differentiation in wave climate and energy parameters. Results compare the performance globally and analyse the rate of change for wave power and its persistence characteristics. Based on results for the spatial distribution and rate of change for wave characteristics, wave power and joint distributions are expected to increase. The study provides novel information with a wave energy development index and rate of change globally, suggesting the most appropriate areas for further assessment based on the discussed criteria.@en

L'uso eccessivo di combustibili fossili sta causando la riduzione delle riserve di carbone, oltre ad un aumento delle emissioni di gas “effetto serra” esacerbando i cambiamenti climatici. Tali condizioni alterano la circolazione dei venti sugli oceani e, di conseguenza, il clima ondoso, con effetti non solo sui regimi medi, ma anche sugli eventi estremi, la cui determinazione risulta di fondamentale importanza per una accurata gestione delle coste e per la riduzione del rischio costiero. L'Oceano Indiano è interessato da intensi cicloni tropicali sia nella zona settentrionale che meridionale (Gray, 1985; DuBe et alii, 1977) ed in quest'ultimo si registrano eventi estremi soprattutto nelle stagioni di dicembre-gennaio-febbraio (DJF) e marzo-aprile-maggio (MAM). Tuttavia, non è ancora chiaro come nelle aree costiere dell'Oceano Indiano meridionale i cicloni tropicali possano evolvere e quale sia l'impatto di tali alterazioni sul regime dei venti e sul clima ondoso. Nel presente studio, sono stati valutati gli eventi estremi sulle aree costiere dell'Africa sud-orientale considerando le proiezioni future secondo uno scenario RCP (Rappresentative Concentration Pathway) 8.5 della quinta fase del modello CMIP5 (Coupled Model Inter-comparative Project). L'analisi è stata effettuata sulla base della variazione stagionale degli eventi estremi sotto costa, al fine di determinare le variazioni nel breve e nel lungo periodo. I risultati indicano che la maggior parte delle aree vicino alla costa africana nel nord e nel sud del Canale del Mozambico, a est e sud-ovest del Madagascar e le coste di Reunion e Mauritius sono soggette ad eventi estremi specialmente durante le stagioni DJF e MAM. Le proiezioni dei cambiamenti del clima meteomarino mostrano una maggiore intensità degli eventi estremi sotto costa quasi in tutte le stagioni. I risultati (Tabella 1) indicano, inoltre, che i valori massimi di velocità del vento nelle aree costiere dell'Africa sud-orientale aumenteranno dell'1% e del 16% nei mesi di settembre-ottobre-novembre (SON) e giugno-luglio-agosto (JJA), mentre durante le stagioni dei cicloni tropicali (DJF e MAM), aumenteranno, rispettivamente, dell'11% e del 4%. Di conseguenza, le altezze significative delle onde estreme aumenteranno in media del 10% durante DJF, JJA e SON. Durante i mesi MAM, nonostante le previsioni mostrino un incremento degli eventi estremi al largo dell'Oceano Indiano meridionale, si osserva una riduzione dell'intensità degli eventi estremi sotto costa, a causa del cambiamento delle traiettorie dei tifoni. Climate change impact assessment is vital in order to investigate not only the change of average wind and wave climate, but also the extreme events. Such kind of events can affect the activities in nearshore areas such as marine operation, as well as on design of coastal and marine structures. In this research, longterm assessment of wind and wave data has been conducted to determine the effect of climate change by comparing the dataset for historical and future projections. The analysis has been done mainly in nearshore areas and the results were discussed in order to evaluate the impact of climate change, quantitatively.

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