Flexible, cheap and easy on the environment, mini-hydropower generators are creating a buzz.

You don't have to change the course of rivers and move mountains to generate electricity.

The hydroelectric power plant perched over an irrigation canal near a roadside rice paddy in Kuroiso, Tochigi Prefecture, is the size of a garden shed.

Making use of a 2-meter drop in the water level, it can churn out 30 kilowatts of electricity, enough to power 50 households.

That's far less than a conventional hydroelectric power plant-even a small dam generates 1,000 kilowatts.

But dotted in brooks and crannies across the country, micro-hydropower units might one day offer a substantial supplement to the national power grid.

Big dams have a bad environmental image. Thermal power stations are blamed for contributing to global warming. Electric power companies and governments are looking for alternatives.

The advantage of small hydropower systems is their flexibility. They can be used in any number of locations, from canals, waterworks and sewer systems to water facilities of large factories.

The facility in Kuroiso, installed in April, is the first test system by Electric Power Development Co., an electric generator and wholesaler.

J-Power, as the company is known, developed the system jointly with a manufacturer. Designed for irrigation canals, the system is targeted at farmers' organizations and municipalities that hold water rights.

The cost to install one unit is roughly 30 million yen. J-Power estimates the operators can recover the cost in about 10 to 15 years by selling generated electricity to power companies.

J-Power, already the nation's biggest generator of hydropower, believes the system could be set up in ``tens of thousands of places,'' says a company official.

Other electric power companies have also started testing the waters.

Japan Natural Energy Co., a subsidiary of Tokyo Electric Power Co., started in April operation of a micro-hydropower unit in the underground water system in Yokohama. The 170-kilowatt facility was installed for 50 million yen.

The company will sell the electricity wholesale to TEPCO, and pay part of the profits to the waterworks department of the Kawasaki municipal government, which owns the waterworks.

Japan Natural Energy aims at producing power at 30 locations, mainly using waterworks, by the end of fiscal 2005.

Micro-hydropower generation is expected to get added momentum from a law that took effect last year, obliging power retailers to use a certain ratio of renewable energy.

TEPCO, for example, can count the electricity bought from Japan Natural Energy as part of its obligations.

The government, as part of its campaign to prevent global warming, is offering subsidies to cover part of the cost of introducing the micro-hydropower systems.

The agriculture, economy and industry ministries launched a committee this spring to share ideas on using the technology. The industry ministry will soon embark on a five-year scouting mission for suitable locations to install the micro-power units.(IHT/Asahi: September 29,2004) (09/29)