*3.2. Technical Specification of Ohito SHP*

Total installed capacity of Ohito SHP is 50 kW and an annual power generation of approximately 320 MWh/year was estimated. This SHP plant contains an irrigation channel/intake/forebay tank. Figure 5 shows the powerhouse of Ohito SHP. The powerhouse is made up of locally available stone to save money and involve the local resources. The generated electricity is sold to the national grid and it is connected to 200 V poles available near the powerhouse. The total length of this channel is 10 km. At the middle of this channel (approx. 5 km), a small desilting tank with a tyrolean type intake weir has been made as shown in Figure 6. The water was first stored in a forebay tank. Since the priority is given to irrigation. The rest water is utilized to produce electricity, and so the amount of discharge changes throughout the season according to water requirements for the crops.

For this site, a cross flow turbine (made in Indonesia by Asosasi Hidro Bandung) has been selected with electrical equipment and a control panel (made in Japan). A high efficiency IPM generator with AC-DC converter (GD) and further on DC-AC converter (GC) have been installed as shown in Figure 7. It is a unique system that increases the system efficiency even on low output and low speed of the generator. An IPM generator is a high efficiency (~95%) varying speed generator, which is approx. 80% efficient at 25% of its rated speed. The combination of GD and GC helps to stabilize the output voltage and frequency according to the grid requirement.

**Figure 5.** Power house (Source: Author).

**Figure 6.** Tyrolean intake with forebay tank (Source: Author).

**Figure 7.** System flow of Ohito SHP (Source: Author).

Table 1 presents the site details and equipment specification installed at 50 kW Ohito SHP. The low cost overseas turbine makes the system cheaper, and a high efficiency electrical system, especially on low load condition, is an attractive concept for other similar community development projects. In a case of SHP construction in Japan, one of the major concerns is a garbage removal process. Due to low capacity, it is not economically beneficial to use an automatic garbage removal system by Tyrolean intake. Another obstacle arises due to powerhouse location (generally in mountainous regions away from the downtown). Someone must go and clean the garbage daily, it costs time, money and effort for garbage removal activities. Keeping that in mind, a Tyrolean type automatic garbage cleaning intake has been constructed.


**Table 1.** Technical details of the 50 kW Ohito SHP (Source: Author).

#### *3.3. Project Financing & Economic Parameters*

The Ohito Agricultural Cooperatives borrowed the loan from financing cooperation and banks. At the same time, they got a subsidy from the Miyazaki prefectural government. Figure 8 represents the construction cost and finance arrangement for the construction. The total cost of construction was USD 896,000. Out of which, USD 94,340 is subsidized by the government of Miyazaki prefecture. The others are arranged by the loan from the local bank of Miyazaki and Japanese Financing Corporation at the rate of interest 2.6% and 0.9%, respectively, within the repay period of 20 year, which is guaranteed by FIT.

**Figure 8.** Business model and finance distribution for the construction of Ohito SHP (Source: Author).

Figure 9 represents a cumulative cash flow estimation of Ohito SHP. The running cost was calculated as approximately USD 8500 per year. The results of economic calculation are as follows: Project IRR (4.3%), B/C ratio (1.36) and project payback period (13 years). In Figure 8, the *x*-axis shows the period. Since the FIT provided by the Japanese government ended for 20 years. The cost analysis was done for a 20 years period. The *Y*-axis gives the cumulative cost per year, which includes total earning−maintenance cost−loan payment per year. The breakeven will be achieved after 13 years by the calculation.

**Figure 9.** Cumulative cash flow of Ohito SHP (Source: Author).

### **4. Discussion**

Installing SHP has several recognizable benefits, including in achieving SDGs from community-based action, and helping in the development of local community people or rural areas, which have limited jobs and facilities.

More precisely, it supports the growth of rural communities and local developers. In the case of Ohito SHP, a local civil engineering company performed all the civil works, local traditional stones and wood were used to build the powerhouse. Furthermore, community people get the benefit by selling electricity to the Kyushu Electric Power Co., Inc., Fukuoka city, Japan (one of national electric power companies), and local companies get work orders, which helps them. As discussed above, the Japanese government gives high FIT by a renewable energy policy, and the FIT provided on SHP of less than 200 kW is 34 yen (US\$ 0.32 per kWh) for 20 years, which means an SHP developer gets high earnings by selling electricity generated from SHP.

From the economic point of view, Ohito SHP generates more than 350 MWh per year. It continuously runs at its full capacity of 50 kW, except for a few months during rice crop harvesting (4 months in a year), during that, capacity reduces to 20 kW. The plant started in January 2018 and within the last approximately 3 years, 1100 MWh energy has been generated as per the data seen on 3 March 2021. The total revenue earned until the mentioned date was = 1100 × 1000 × 0.32 (FIT price) = 352,000 US\$. On average, 350 MWh energy has been generated in the last 3 years. If the plant runs similarly as now, it is possible that the developer will achieve the breakeven point sooner than estimated.

The energy output and power generation for the last month of 10 April 2021 to 10 May 2021 is shown in Figures 10 and 11. It shows the variation of power output and power generation with the time. It shows that power output and energy generation was constant until 2 May 2021, and then afterwards, it reduced to 1/3 of designed output. Generator power and power going to the grid with respect to time and water pressure have been shown in Figures 9 and 10. It has been seen that until 2 May 2021, the power output was 50 kW approximately, but after this date, the output decreased from 50 kW to around 17 kW. It is because the water is being used for irrigation purposes, which has priority over power generation. This shows a new community-based business of the Ohito community integrated in agriculture and hydroelectric generation at the local level.

**Figure 10.** Power generation and supply to grid (Source: Author).

**Figure 11.** Energy generation per day in kWh. Approximately 1 MWh energy was being generated until 2 May 2021, which has decreased to 400 kWh after starting agricultural activities. The water is used for rice crop irrigation (Source: Author).

From the environmental point of view, the SHP development supports the government's efforts to promote clean energy sources and to carry out its target of SDGs, as an SHP uses water to produce electricity without consuming it. The Ohito SHP uses the existing wastewater in the irrigation channel to produce useful clean renewable energy. In terms of specific SDG, Ohito SHP supports targets 7, 8, 13. With respect to CO2 reduction, since, per kWh of electricity generated from SHP reduces 0.463 kg CO2, the 350 MWh of electricity generated annually by the Ohito SHP will lead to reduce approximately 162 tons of CO2 per year.

In terms of social contribution, a community-based SHP leads the local growth by providing work to local companies, utilizing local resources and providing a means of engagement to the local young people and a learning opportunity to the students in the community. Like other communities in rural Japan, the Ohito community is also facing ageing, lack of job opportunities, depopulation, etc. Installing this kind of SHP will provide local empowerment and revival of local business. The sole idea to install the Ohito SHP was as follows:


However, unfortunately, there was no such work done until the writing of this paper. All the money (~35,200 USD) is still being kept by the local community. No such investment has been made. Therefore, the direct social impact of installing this plant has not started yet, but there were some indirect social impacts in terms of idea sharing and attracting other communities to install similar SHP projects in respective communities. In addition, it is a source of education for the community people and university students, as they learn not from theory, but by looking at the actual running plant. There is one more hidden important impact. The Ohito community was getting implicit know-hows and community experiences "of the local community, by the community, for the community", by actually operating SHP.
