Fukushima's Micro-hydro
Published on by Water Network Research, Official research team of The Water Network in Government
Surrounding Towns of Fukushima Wrestling with Funding to Become Indipendant of Nuclear Power, Micro-hydro Could Play a Major Role
The 2011 Great East Japan Earthquake and tsunami, which triggered a nuclear disaster and prompted a national debate on energy policy, has added a new role for a historic canal that draws water from Lake Inawashiroko to this castle town.
Water from the Tonokuchiseki canal, which took more than two centuries to build during the Edo Period (1603-1867), irrigated rice paddies, filled castle moats and supported people's lives.
The canal runs about 170 kilometers in total, including its main and branch conduits.
Water flows out ceaselessly from the "Domon" rock tunnel here, which marks the exit point of the canal on the castle town side. The tunnel, within sight of Tsurugajo Castle, is on Mount Iimoriyama, where the young warriors of Byakkotai (White tiger unit) committed tragic suicide in 1868 at the height of the Boshin civil war.
Byakkotai is a unit of warriors set up to defend the Aizu Domain and the ill-fated shogunate from the armed forces of the new government. Twenty teenage boys of Byakkotai's Shichu Nibantai (high-ranking warriors No. 2) platoon waded through the tunnel to reach the castle town following a rout in the battle in Tonokuchihara, which is located by the side of Lake Inawashiroko. Tradition says they decided to take their own lives using their swords when they saw the castle town in flames.
Japan's rapid modernization during the Meiji (1868-1912) and Taisho (1912-1926) eras added another role for the canal. Three hydroelectric power plants were built in succession to supply power to the city of Aizu-Wakamatsu. The plants, which came under the ownership of Tokyo Electric Power Co. after World War II, remain up and running to this day.
"Water that is necessary for irrigating farmland is directed into the canal," said Kenji Iwasawa, head of TEPCO's Inawashiro electric power control center. "Our power plants only use that much water to generate electricity."
Water is returned to the canal after being used to generate power. Farther downstream, that water irrigates rice paddies, fills the moats, and is used as tap water in the city of Aizu-Wakamatsu and for other purposes. The tradition of water sharing, which began in the Edo Period, continues.
GENERATING POWER FOR LOCAL CONSUMPTION
The canal has taken on a new role in the energy supply after the March 11, 2011, earthquake and tsunami, which caused a triple meltdown at the Fukushima No. 1 nuclear power plant.
The Tonokuchiseki land improvement agency, its administrator, has decided to tie up with Asano Taiseikiso Engineering Co., a Tokyo-based operator of renewable energy and other projects, to start micro-hydropower generation.
The plan calls for Asano Taiseikiso to set up a company, which will build a micro-hydropower station with an output capacity of about 130 kilowatts midway along the canal and sell the power it generates to Tohoku Electric Power Co. The land improvement agency will provide the canal water and the land plots for the site and will take charge of the maintenance of the power generation facilities.
"Just calling out the slogan that ‘I thought Fukushima should lead post-disaster rebuilding efforts' will lead you nowhere," Tetsuyuki Sato, chief of the land improvement agency, said. "We have to do something sooner than later."
Sato was explaining how he came upon the idea of using canal water for micro-hydropower generation. Construction will begin next spring, and power generation is expected to start in autumn next year.
The mainstream approach in micro-hydropower generation involves taking water from rivers, irrigation canals or other conduits into an aqueduct, using natural height gaps to generate electricity, and returning the water to its origin stream after use.
Micro-hydropower plants usually have small output capacities of less than 1,000 kilowatts, but do provide a stable supply of power both day and night. While solar power plants cannot generate electricity at night and their output depends on the weather, micro-hydropower plants can provide about five times more electricity for the same output capacity. For example, a micro-hydropower plant with an output capacity of 200 kilowatts can provide as much electric power as a "megawatt-class" (1,000 kilowatts in output capacity) solar power plant.
One candidate site for a feasible micro-hydropower generation project is located near Mount Iimoriyama.
"Using the power generated there to illuminate Tsurugajo Castle and Mount Iimoriyama would allow citizens to realize how locally produced electricity is being consumed locally," Sato said. "I wish to turn Aizu-Wakamatsu into that sort of leading-edge city."
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