After Fukushima disaster, Japan search the right renewable energy to replace nuclear energy. They’ve stopped renewable energy that has supplied 40% energy. Japan has big potential in hydropower because many rivers that can be installed micro hydro power plants. So, they will develop small hydropower as alternative to replace nuclear power.

In July 2012 the Ministry of the Environment released the results of its investigation into the potential for small and medium hydropower in the form of the Study of Basic Zoning Information Concerning Renewable Energies. Small hydropower refers to hydropower generation with an installed capacity of 10,000 kW or less. Japan’s cumulative installed capacity for FY2010 was 3.24 million kW, according to a report by the Institute for Sustainable Energy Policies (ISEP)

The investigation by the Ministry of the Environment revealed that there is the potential to install 8.98 million kW-worth of installed capacity for small and medium hydropower in river channels, and that there are approximately 19,700 sites for this. This potential for the small and medium hydropower was calculated as follows: the energy resources that can be introduced on account of the amount that can be logically calculated given factors like river flow rates, excluding the energy in regions where it would be difficult to install plants due to constraints arising from regulations and technical capacity, and also excluding energy from existing power plants.

One recent example of the introduction of hydropower is the Tateyama Alps Small Hydropower Generation Project (installed capacity of 1,000 kW) along the Kohayatsuki River in Toyama Prefecture, which went into operation in April 2012. This project was chosen as a Collaborative Power Generation Project with Citizens by the Ministry of the Environment, and marks the first time that small hydropower generation project has been performed in Japan through a civil fund.

Fig.  Results tabulating small and medium hydropower potential (in river channels, excluding existing facilities)
(Source: FY2011 Study of Basic Zoning Information Concerning Renewable Energies, Ministry of the Environment
http://www.env.go.jp/earth/report/h24-04/index.html)

Fig.  Distribution chart for small and medium hydropower potential (in river channels, excluding existing facilities)
(Source: FY2011 Study of Basic Zoning Information Concerning Renewable Energies, Ministry of the Environment
http://www.env.go.jp/earth/report/h24-04/index.html)

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