Design of the Jlantah Reservoir Mini-Hydro Power Plant, Karanganyar Regency, Central Java Province

Abstract An increase in the number of electricity users in Jatiyoso District, Central Java, has occurred in the last few years. In 2020 there were 12,773 families using electricity in Jatiyoso District, where there has been an increase of 79 families using electricity compared to 2019. This increase in electricity demand should be balanced with an increase in sources of electrical energy for the community. Therefore, Jlantah Mini-hydro Power Plant is expected to become a source of electrical energy for the local community. The normal water level of the reservoir is planned at an elevation of +691.00 MASL and the elevation of the intake structure at +661.00 MASL. The total dead storage of the reservoir is 1.66 million and the total effective storage is 9.16 million. The powerhouse elevation planning is carried out by analyzing the 100-year return period of flood in the river around the powerhouse. The powerhouse is planned at an elevation of +624.00 MASL. The turbines used in the powerhouse are 2 turbines. Turbine 1 with HLA550-WJ-55 series and turbine 2 with HLA678-WJ-50 series. The average power generated in a normal year (2013) is 516.44 kW with a total energy of 4.47 GWh. The construction cost of the Jlantah PLTM is estimated at IDR 18,795,716,076.00 with normal annual income (2013) of IDR 4,060,935,522. With this income, the NPV value is IDR 4,461,454,224, IRR is 12.96%, BCR is 1.24, and PBP is 12.78 years, so this project is said to be economically feasible.