Novel turbine design to help tame oceans for clean energy

In an important step towards development of green energy, Japanese researchers have developed a new prototype of a turbine to efficiently harness energy from ocean currents.

In various experiments to test its design and configuration, the turbine was found to have robust construction and it achieved efficiency comparable to that of commercial wind turbines, a study said.

The turbine is especially suitable for regions regularly devastated by storms and typhoons, such as Japan, Taiwan, and the Philippines, the researchers noted.

"Our design is simple, reliable, and power-efficient," said one of the researchers Katsutoshi Shirasawa, staff scientist at Okinawa Institute of Science and Technology Graduate University (OIST) in Okinawa, Japan.

In the journal Renewable Energy, the OIST researchers proposed a design for a submerged marine turbine to harness the energy of the Kuroshio Current, flowing along the Japanese coast.

The turbine operates in the middle layer of the current, 100 metre below the surface, where the waters flow calmly and steadily, even during strong storms.

The turbine comprises a float, a counterweight, a nacelle to house electricity-generating components, and three blades.

Minimising the number of components is essential for easy maintenance, low cost and a low failure rate, the researchers explained.

Water is over 800 times as dense as air, and even a slow current contains energy comparable to a strong wind, making ocean currents a viable source of clean and renewable alternative to fossil fuels.

The new turbine design is a hybrid of a kite and a wind turbine - an ocean current turbine is anchored to the seabed with a line and floats in the current while water rotates its three blades, the researchers said.