Linking the long-term variability in global wave energy to swell climate and redefining suitable coasts for energy exploitation

Abstract

The sustainability of wave energy linked to the intra- and inter-annual variability in wave climate is crucial in wave resource assessment. In this study, we quantify the dependency of stability of wave energy flux (power) on long-term variability of wind and wave climate to detect a relationship between them. We used six decades of re-analysis wind and simulated wave climate in the entire globe and using two 30-yearly periods, we showed that not only the previously suggested minimum period of 10 years for wave energy assessment appears to be insufficient for detecting the influence of climate variability, but also the selection period for wave energy assessment can lead to an over/underestimation of about 25% for wave power. In addition, we quantified the dependency of rates of change of wave power, wind speed and wave parameters and showed that the change in wave power is mainly a function of change in swell wave climate globally. Finally, we redefined the suitability of global hotspots for wave energy extraction using intra-annual fluctuation, long-term change, and the available wave power for the period of six decades. The results highlight the importance of climate variability in resource assessment, sustainability, and prioritizing the hotspots for future development.

Wave Power Trends over the Mediterranean Sea Based on Innovative Methods and 60-Year ERA5 Reanalysis

“…Moreover, Reguero et al (2019) [27] underlined that increasing global wave power is linked to global warming. Kamranzad et al (2022) [32] showed that the change in P wave is mainly related to the global swell climate. In addition, they found a decreasing change in the western and eastern Mediterranean Sea and an increasing change in the central Mediterranean Sea when the mean annual P wave was compared over 30-year periods.…”

“…However, an increasing trend case is not observed at all locations. According to Kamranzad et al (2022) [32], the change in wave power is mainly related to the change in the swell climate globally. Therefore, they pointed out the significance of focusing on these long-term changes when choosing appropriate locations to install wave farms.…”

Global extreme wave estimates and their sensitivity to the analysed data period and data sources

“…SWAN Cycle III version 41.31 was used to model the JRA-55-based wave hindcast data. The SWAN model has been used to accurately replicate the global wave climate (Yang et al 2017;Kamranzad and Mori 2019;Liang et al 2019;Kamranzad et al 2020Kamranzad et al , 2022.…”

CMIP6 projections for global offshore wind and wave energy production (2015–2100)

“…Other additional aspects like local and international legislation, stability, risks evaluation or even model specifications must also be incorporated into any feasibility assessment study 10 . Assuming a lifetime of several decades during which profitability must not be compromised, this applies not only to present-day conditions but also to their future evolution 11 . An additional aspect mentioned in the IPCC reports 12 is the rise in sea levels, and this also needs to be considered in the feasibility analysis of any offshore wind or wave farm.…”

“…The figures have recently been released 18 and include three-hourly global ocean wind and wave data corresponding to the 1961-2100 period for the SSP585 and SSP126 scenarios 19 , 20 . Following the guidelines provided by referential studies 11 and institutions in the definition of standard climate norms 21 , a 30-year period from 1985 to 2014 was selected to define present-day conditions.…”