Wave Energy Resources Along the European Atlantic Coast

Ocean wave energy has become the focus of governments and energy companies over the past decade. In spite of its unpredictability, this untapped source of energy appears to be a sustainable alternative to traditional sources of energy such as thermic and nuclear energies, or hydropower, all of which pose significant environmental and geopolitical problems. Open to the Atlantic Ocean at latitudes between 35°N and 65°N, the Atlantic Coast of Europe is blessed with one of the highest wave powers in the world—estimated to be between 33 and 76 kW/m wave crest. The European Commission has taken a proactive attitude towards encouraging and promoting the development of marine renewable energy during the near future. In this context, the European transnational project EnergyMare was commissioned to investigate the potential of marine renewable energy resources on the European Atlantic Coast as well as test innovative measurement techniques and promote the development of test sites. The targeted wave energy resources were assessed via a 10-year hindcast, using state-of-the-art spectral wave models WaveWatch III and SWAN set up on unstructured meshes or fine-resolution regular grids. The hindcasts were combined to simultaneously provide a holistic view of the wave energy distribution across the European continental shelf and fine-resolution maps of specific areas, in particular around archipelagos and complex coastlines, where wave characteristics can be affected by the presence of small islands, headlands, or irregular bathymetry, and at wave energy test sites. The domain size and timescale of the hindcasts enable a comprehensive description of the wave climate along the European Atlantic Coast, both in terms of its distribution and its seasonal and interannual variations. In particular, a comparison of wave activity at various coastal locations shows its dependence on latitude and arguably its more significant dependence on exposure to open Atlantic waters. Wave activity during the winter months is clearly predominant, but dominant peak activity was also occasionally observed during spring and autumn. In spite of increased winter wave activity over the past couple of years, data are insufficient to enable conclusions to be made about a persistent trend in the international wave climate. Continental-scale mapping of wave energy resources together with fine-resolution mapping of coastal areas provides an overview of the wave resources to help identify the best areas for energy or test sites. Such mapping also provides information about local wave characteristics and resources that can be used for diminishing installation risks or optimising a site by selecting the most appropriate devices or array configurations. In addition to evaluating wave resources, fine estimates of energy yield from a site may require a good understanding of the wave interaction in an array of converters where significant wave interference may be induced. Finally, long-term trend estimates or periodic re-evaluations of wave resources to address potential wave climate change will probably be necessary to achieve sustainable wave energy exploitation.