The objective of this research is to guarantee that the building of PLTMH Bayang Nyalo achieves maximum energy output and utilizes possible renewable energy sources in a sustainable and efficient manner. This research is a study that aims to describe and analyze data using a quantitative technique. The quantitative research technique is used when study data is in numerical form. Quantitative descriptive research is a method used to examine obtained data by providing a detailed and accurate description of the data. This study aims to determine the optimal value for designing small-scale hydropower plants (PLTMH). In order to do research for this thesis, the author investigates the number of studies performed in the Bead Dam Nyalo Kec. Nagari Bayang North, South Coast Regency West Sumatra. The PLTMH project aims to harness the water flow from the subterranean river, which has a discharge rate of 14.67 liters per second. The power plant is designed to have a power capacity of 623.32 kW, using a high discharge waterfall with an effective height of 5 m. Based on the examination of technological elements, we have reached conclusions: The civil component of this PLTMH includes a gravity concrete dam that is prepared for operation, while the electrical components consist of a Cross flow Turbine. The development of mechanical transmission is ongoing.