Since the closure of the Strait of Hormuz, securing energy has once again become a pressing issue. Currently, after the temporary use of nuclear power, there is a shift towards renewable energy. Petrochemical fuels have the advantage of being easy to use due to their high energy density. To obtain the same amount of energy from renewable sources as from oil, a large quantity must be collected. For example, with solar power, the challenge lies in how widely solar panels can be installed. To obtain the same amount of electricity from solar power as from oil or coal, a vast area is required. In this respect, hydropower has advantages. Compared to solar and wind power, it is less affected by weather, can generate electricity for long periods, and has high equipment efficiency. When using renewable energy, considering renewable energy suitable for local areas is also an option.
In the village of Yoshinogari in Saga Prefecture, there is a small-scale hydropower plant operated with investment from the residents. This power plant is a white container nestled in the mountains. That container is the Matsukuma Small-Scale Hydropower Plant. The small-scale hydroelectric power plant utilizes an existing irrigation canal, drawing water from the Tategawa River that flows through the area. The water pressure from this canal, with a height difference of 21.9 meters, continuously powers the turbine inside the container. Its operating status can be checked via smartphone. It began operation in November 2020 and is a small power plant with a maximum output of 30 kilowatts. Five years into operation, it has been a hard-working asset, bringing the community approximately 10 million yen in extra income. Annual electricity sales revenue is around 8 million yen. After deducting expenses such as loan repayments (47 million yen), the district’s annual profit is approximately 1.9 million yen. This profit has been used to implement various improvements to the community’s life. These include subsidies for shared taxi fares, cooking classes for men, and rental of agricultural equipment. The power plant’s profits are also used to fund local events, creating an environment that residents actively participate.
It would be interesting to see what happens if villages and towns have the capability to plan, develop, and operate hydroelectric power plants. If we were to pursue this more proactively, it would involve building dams in towns and villages. For a 500kW power generation capacity, the construction cost would depend on the river conditions, the shape and status of the dam, but it is estimated to be around 700 million yen. This 700 million yen would be financed through loans from financial institutions. Depending on the loan conditions, the 700 million yen could be repaid over 15 to 18 years. For a 500kW power generation capacity, the annual electricity sales revenue would be approximately 73 million yen. If 60 million yen of that is used for loan repayment, 13 million yen remains. From this 13 million yen, approximately 6 million yen per year would be deducted for maintenance costs such as personnel expenses for the power generation facility. This leaves 7 million yen. This 7 million yen is the profit during the period when the initial costs are being repaid. After 15 to 18 years, when the loan repayments are finished, an additional 60 million yen in profit will be generated. This will become the independent financial resource of the municipality. It would be wonderful if such a scenario could be realized.
