Flowing water resurfaces as untapped power source

Water wheels began disappearing from the landscape with the advent of steam engines, but, as Japan searches for alternative power sources in the wake of the Fukushima No. 1 nuclear plant disaster, flowing water is once again being eyed as a power source.

The three-meter tall metal box installed in a watercourse beside Yodogawa-Ozeki dam in Osaka by the Kinki Regional Development Bureau of the Ministry of Land, Infrastructure, Transport and Tourism this March doesn’t quite have the charisma of an old-style water wheel but it serves essentially the same function.

Water flows through the box, rotating two cylinder-shaped turbines and generating a steady flow of about two kilowatts of electricity. The power is used at the bureau’s office at the dam.

The developer of the device, Seabell International Co. in Tokyo’s Chiyoda Ward, currently has only 11 employees, but director Shunichi Maeda said it aims to cut prices by achieving further technical innovations and moving to mass production.

Inquiries from other local governments have increased sharply since the March 11 Great East Japan Earthquake, and one local government in eastern Japan is already planning to install 100 10-kilowatt water boxes and then sell the electricity they generate.

Akira Nakagawa, president of Nakagawa Suiryoku in Fukushima Prefecture, another leading developer, said his firm has also noticed an uptick in visits from local politicians and others following the quake.

A hydraulic generator made by the firm, which can generate power from water flowing down a two-meter drop, is already being used in irrigation channels in Nasushiobara, Tochigi Prefecture, and Nakagawa says a turbine that can generate power from only a 50-centimeter drop is under development.

Tanaka Suiryoku Co., a small company in Zama, Kanagawa Prefecture, with 31 employees, has developed Japan’s first “turgo” water turbine for a small-scale hydraulic power generation project run by the Ohisama Energy Fund in Iida, Nagano Prefecture.

The fund plans to install the turbine on the Kohayatsukigawa river in Uozu, Toyama Prefecture, in April next year, and projects an output of about 1,000 kilowatts, still only a fraction of the 1 million kilowatts that can be pumped out by a nuclear reactor but a significant output for a hydraulic generator.

The construction cost of about 1.05 billion yen ($13.6 million) will be covered by subsidies and investments of 780 million yen from private citizens.

But, while such projects are showing the potential of flowing water as a power source, makers say the spread of the modern-day water wheels may largely depend on the way the special measures law on renewable energies, which passed the Diet in August this year, is implemented.

The law obliges electric power companies to purchase electricity produced from renewable energy sources at fixed prices over defined periods, but those prices have yet to be decided.

“Since the March 11 disaster, we have received a growing number of inquiries on (installation or other) costs. But we have not concluded any contracts yet. Everyone is waiting for decisions on the prices,” said Akihiro Tamura, president of Tanaka Suiryoku.