Among renewable energy advocates in Japan, one often hears the phrase “chisan chissho,” or “local production, local consumption.” In the past, it referred the promotion of local-level agriculture. But it’s now becoming a call to reduce municipalities’ reliance on electricity from fossil fuel and nuclear power plants hundreds of kilometers away.

Small hydropower plants represent the local production, local consumption concept perhaps better than any other form of renewable energy.

Unlike the nation’s infamous large-scale dams — symbols of pork-barrel politics approved by corrupt Tokyo politicians and bureaucrats and their collusion with huge construction companies — “micro-hydro” plants have an image of being environmentally friendly regional projects that actually benefit their communities.

Discussion can be confusing, though, when it comes to “large” versus “small” plants because of how the government labels them.

“Large” hydropower plants are defined by the Environment Ministry as those that generate more than 100,000 kw. “Medium” hydro plants generate between 10,000 kw and 100,000 kw. “Small” hydro plants are defined as those that generate between 1,000 kw and 10,000 kw. “Mini” hydro plants generate between 100 kw and 1,000 kw, and “micro” hydro plants are those that generate less than 100 kw.

Whatever the scale, hydropower in general tends to be viewed more favorably by officialdom and the utilities, less because of its green credentials and more because it’s seen as a stable source of electricity in a mountainous nation with more than its fair share of precipitation. Small hydropower’s advantage, though, is that it does not mean damming up large rivers, but rather harnessing the power of flowing water — regardless of whether its a natural river, stream, or man-made agricultural canal or public reservoir.

Major utilities, as well, admit hydroelectricity’s future is in smaller projects because there are no more large rivers to dam up.

“Hydroelectric power is one of the few self-sufficient energy resources in resource-poor Japan,” says the Federation of Electric Power Companies of Japan in “Electricity Review Japan: 2011.” “It’s an excellent source in terms of stable supply and generation cost over the long term. Japan has used nearly all available sites for construction of large-scale hydroelectric facilities, and recent developments have been on a smaller scale.”

One smaller scale project that is an example of local governments and the private sector working together is the Toyonaka hydroelectric plant in Osaka Prefecture. The plant generates 129 kw, with the flow of water coming from the Senri reservoir, about 7 km away. It cost about ¥100 million to build, with a third of the funding coming from the New Energy and Industrial Technology Development Organization. Maintenance costs are about ¥2.5 million annually.

“Water from the reservoir, which is about 35 meters higher in elevation than the Toyonaka plant, flows into the turbine. The electricity generated operates the plant itself, and is supplied to Kanden Energy Development Co., which sells it to Kansai Electric Power Co.,” said a spokesman for the Toyonaka Waterworks and Sewerage Bureau.

In its 2010 status report on renewables, the Japan Renewable Energy Policy Platform, a nongovernmental organization made up of eight different groups involved in renewable energy, said small hydropower capacity (plants with 10,000 kw or less by their standards) totaled 3,225 megawatts at 1,198 plants as of March 2009.

The report noted that these plants accounted for 6.6 percent of the nation’s total hydropower capacity, and that construction of new, smaller hydro plants like the one in Toyonaka has been slow for at least two decades.

“Most domestic small hydropower plants were built before 1990, and only 127 plants accounting for a total capacity of 166 megawatts were constructed after 1990,” the report said.

Dai Nakajima, a spokesman for the National Small Hydropower Association, reckoned Japan is now about a decade behind the U.S. in small hydropower plant development, and that overcoming the high price of hydroelectricity generation through an effective feed-in tariff over a long period of time is necessary.

“The cost of mini-hydroelectric power ranges between ¥15-¥100 per kilowatt-hour. Power companies don’t object to buying the energy from mini-hydro plants. But their cost per kilowatt-hour is a problem,” he said.

In addition to cost, other problems facing the mass introduction of hydropower plants include finding downstream locations that ensure a stable water flow, and hence cost-effective output. Legal, bureaucratic and municipal land- and water-use issues also come into play.

The Ministry of Economy, Trade and Industry estimates there is about 12.1 million kw in total untapped hydroelectric power at over 2,700 locations in the country that would be economically and technologically feasible to develop. Of those, hydro plants of less than 1,000 kw could be developed at 371 sites and have a potential capacity of about 242,000 kw.

To develop even a fraction of the sites, METI said, would take increased political will and central government financial incentives. But Kazumi Yagi, writing in the July 2010 issue of the newsletter Japan for Sustainability, advocated the local production, local consumption theme by suggesting small-scale local-level projects like the one Toyonaka has undertaken could be a template for future development.

“In the past, communities handled the maintenance and management of small hydropower stations locally,” he wrote. “To return this responsibility to communities, it’s necessary to model efforts after a structure in which projects are led not by electric companies, but by local governments, land improvement districts, NPOs, businesses and individuals.”

Additional reporting by Yuki Asano

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