Wave energy converters in low energy seas: Current state and opportunities

Existing wave energy technology has been designed for ocean waves, which, however, shorten the lifespan of wave energy converters and mooring systems. Furthermore, commissioning and maintenance in the harsh ocean conditions are challenging and expensive. For wave energy technology to realise its full potential and become commercially attractive, smaller, more economical, and resilient converters should be first introduced, tested, and optimized, as was the case with wind energy. Low energy seas such as the Mediterranean, Baltic, Caspian, Black, and Red Sea are ideal for this purpose. However, the body of knowledge on wave energy converters is limited and primarily focuses on the Mediterranean. Low capacity factors have been reported, which suggests that existing technology should be downscaled to fit the milder wave regimes. Climate change tends to increase the wave energy resource, which could be beneficial for wave energy harnessing, however, will greatly affect beach and coastal erosion and ports functionality. Converters in the nearshore can protect ports and the coast and mitigate erosion. Other secondary functions include desalination, hydrogen production, pumped-storage hydroelectricity, photovoltaic panel integration, and wave-wind farms co-location. Even though wave energy converters can counter beach erosion, they might also negatively affect aquatic ecosystems through vibrations and low-frequency long-duration noise, but little attention has been paid to their environmental impacts. Overall, wave energy can increase renewable energy penetration, decarbonize power generation, and promote job creation, and low energy seas can play an important role in advancing existing technology and help the industry progress.