Shikoku whirlpool study of Naruto Strait shows atomic potential


The tidal energy created in the Naruto Strait between Shikoku and Awaji Island — famous for its spectacularly large whirlpools — is equivalent to the power generated by four nuclear reactors, a study commissioned by Tokushima Prefecture has discovered.

The prefectural government, however, stressed “it is not easy to achieve the practical use of tidal energy,” noting that the development of technology to harness such power is still in its infancy.

“The Naruto Strait is a key shipping lane and the installation of power-generation equipment could cause the whirlpools to disappear,” it added.

The research, conducted by the University of Tokushima, surveyed an area of about 40 sq. km centering on the narrow strait where the tidal current is at its most powerful. Dividing the area into 165 sections, the university calculated the tidal energy of each section based on data such as the maximum current speed and average undersea area.

The study estimated that the tidal energy generated at the center of the Naruto Strait to be a maximum of 260 megawatts, with approximately 4 gigawatts generated across the whole area.

The Naruto Strait is designated as a national park and development in it is severely restricted. It is also a major shipping lane providing a transit route to some 350 ships every day, and has fertile fishing grounds.

“The research results showed just a theoretical potential. They do not mean that the indicated amounts of energy can be generated,” Toru Shigemitsu, associate professor at the University of Tokushima Fluid Machinery Laboratory, said. “It is important to continue technological development and experiments, without considering that the tidal energy (in the strait) can be put to immediate use.”