Currently, the capacity of electric power facilities in Japan is about 250 million kW. This power facility produces about 1 trillion kWh of electricity per year in Japan. The capacity of thermal power generation is 160 million kW. Before the Great East Japan Earthquake, 54 nuclear power plants had a capacity of about 50 million kW, which covered 26% of Japan’s total. The rest was covered by hydroelectric power generation, solar power generation, biomass power generation, geothermal power generation, small hydroelectric power generation, tidal power generation, wave power generation, etc. However, since the nuclear power plant accident, the burden of thermal power generation and renewable energy has increased. Japan’s electricity situation is made up of a combination of various sources of electricity. In this context, small hydroelectric power generation is attracting attention.
Small hydroelectric power generation can generate 0.5 kW of electricity even with a head of 1m. It is said that the construction cost to generate 1 kW of electricity is $14,000. If it is operated well, a small hydroelectric power plant with a drop of 2 m and a capacity of 1 kW can be sold for $1,400 per year. For example, if there are five erosion control dams in a mountain stream, each one can generate electricity. If there are five erosion control dams, all of them can generate small hydroelectric power. Even a small erosion control dam with a height of about 10 m can generate electricity and produce 200 kW of electricity. If it is 200 kW, five of them will be 1000 kW, and it will be possible to sell electricity for $1.4 million.
One such example is in the Sasagawa district of Asahi Town, Toyama Prefecture, which has a population of about 250 people. A construction company in Sendai City, Miyagi Prefecture, is setting up a power plant and selling electricity. Small hydroelectric power generation using the Sasagawa River that flows through this area will begin in 2023. The 196-kilowatt power plant will be large enough to generate electricity for about 400 households. The electricity generated by this power plant will be sold to Hokuriku Electric Power. The revenue from the sale will be used to upgrade the water infrastructure. The management and operation of the power plant will be handled by the Sumire Regional Trust (Takayama City, Gifu Prefecture). The reason for adopting the trust system was that “we wanted to ensure that the plant would continue even if the company in Sendai went bankrupt.” The aim is to increase the sustainability of areas suffering from depopulation by utilizing local small hydropower resources. This method is an example that gives hope to regional revitalization. In Japan, there is a proverb that says, “The journey of a thousand miles begins with a single step.” It seems that local production and consumption of electricity will also be an option.
