Installed in April this year, the plant is the size of a garden shed and makes use of a 2m drop in water level. It is the first test system installed by Electric Power Development Co., an electricity generator and wholesaler known as J-Power, which developed the system for irrigation canals and is targetting farmers’ organisations and municipalities that hold water rights.

The cost to install a unit is roughly US$280,000, while J-Power estimates operators would be able to recover their costs within about 10 to 15 years by selling electricity to power companies.

Other companies that have started testing mini hydro plants include the Japan Natural Energy Co., a subsidiary of Tokyo Electric Power Co., which started the operation of a micro hydro power unit in the Yokohama underground water system in April. The 170kW facility was installed for around US$470,000.