Estimation of the Technical Resource for Tidal Stream Energy in South-West Japan

To reach the objective of net-zero carbon by 2050, Japan is promoting the development of renewable energies. Among these, tidal current energy provides high predictability and stability, which can help mitigate the negative impact of the high variability of other sources (solar, wind) on the grid management. As an initial step for the design of a tidal current energy national development plan, this paper presents a resource analysis for South - West Japan. Results for current velocity from an ocean numerical model were used to identify tidal energy sites and estimate the theoretical resource for each of them. Applying the same ocean model results to the specifications of nine turbines, energy output was estimated for each site. Results showed an estimated installable capacity of 4,422.5 MW and an annual energy yield of 8,956.06 GWh. More than 78% of this resource is allocated in only six areas or sites: the straits between Goto Islands, the entrances to Ariake Sea, Hayasui Strait, Kurushima Strait, Bisan Strait, and Naruto Strait. Though this work provides valuable insights for the theoretical and technical resource in South - West Japan, further research is needed to evaluate the economical viability of tidal energy exploitation in each site.