To discover sites suitable for ocean current power generation, we conducted acoustic Doppler current profiler (ADCP) and conductivity temperature- depth (CTD) measurements from 31/8/2010 to 2/9/2010 at Miyake Island. Strong ocean current is expected at Miyake Island, which is located approximately 180 km south of Tokyo and often exposed to the Kuroshio Current. The estimated horizontal and vertical velocity profiles revealed convergence of the current through a narrow passage between Miyake Island and a small island to the west, where the observed current speed reached 2.5 m/s. A synthetic aperture radar image indicated features consistent with the ADCP observations, such as the strong current shear at the boundary of the island wake.
Ocean current power generation using the Kuroshio Current is feasible and desirable around the Izu Islands for several reasons. First, the current is quite strong, often reaching 2 m/s. Second, the shallow water depth would allow for easier and more cost-effective power plant construction than in the deep ocean. Finally, because of the cost of transporting oil, the existing electricity supply system on the islands is expensive, reaching nearly five to ten times that of mainland Japan. The details of the analyses that led to these conclusions are described in our previous report (Kodaira et al. 2009). However, our earlier study was based on an ocean current reanalysis, which limited the resolution to a 10-km horizontal grid. Therefore, the situation at Miyake Island was barely resolved. To obtain higher resolution information, we conducted ship-based acoustic Doppler current profiler (ADCP) and conductivity temperature- depth (CTD) measurements from 30/8/2010 to 2/9/2010 around Miyake Island.
Miyake Island is located approximately 180 km south of Tokyo (off Honshu Island, mainland Japan) on the Izu Ridge. Therefore, a strong current was expected near Miyake Island.
