Preliminary design of micro hydro power plant in Enim river, Plakat village

The utilization of renewable energy in meeting electricity needs in Indonesia continues to be carried out, including by utilizing river flow as a source of electrical energy for the community. Micro hydro power plants are one type of power plant that utilizes river flow as a source of energy that is widely used in Indonesia, especially for people in rural areas who have difficulty in accessing the electricity grid and spread throughout Indonesia. One of the rivers in South Sumatra Province, Indonesia that has the potential to be developed as a micro hydro power plant is the Enim River located in Plakat Village. This research was conducted to obtain an estimate of the amount of energy that can be generated from the Enim River. In the methodology, the data needed to calculate the amount of energy produced includes effective the effective fall height data, identification of the intake channel, forebay and penstock pipe obtained from direct observation and then the calculation of water power that can be generated by the Enim River tributary in Plakat Village. In the calculation results, the micro hydro design in Plakat Village, Enim River is as follows: 184 m pipe dimensions, minimum pipe thickness of 0.5 m, effective energy height of 26.1 m, and output power of 35.88 kW.


Introduction
As the population grows, the need for electricity in rural areas increases, but, on the other hand, the financial support by the government to expand the electricity network is limited [1].Energy is one of the important things in human life [2] and energy has an important role in the development of a country if its availability and development are hand in hand and support national development [3]- [5] .Micro-hydro is often considered as a plausible alternative in meeting the electricity needs of rural communities [1].Utilization of rivers as micro hydro powerplants by utilizing rivers as an energy source has been widely carried out in the territory of Indonesia, considering the number of riveris scattered throughout the waters in Indonesia, including in East Java, West Sumatra, Aceh, South Sumatra, and other area in Indonesia [6]- [10], is more reliable and cheaper than the generator with other raw materials and is included in renewable energy [11], [12].
Prior to the construction of a micro hydro power plant, there are several things that should be done, namely the potential surveys and development feasibility [13]- [15].South Sumatra Province has areas that have renewable energy potential.Muara Enim Regency has a fairly large area and abundant natural resources with most of its area being a watershed.This area includes Semende Darat Ulu, Semende Darat Laut, Semende Darat Tengah and Tanjung Agung subdistricts.The lowlands are in the middle.In the northwest-north, there is a swamp area directly facing the flow of the Musi River.
The potential in the Semende Darat Ulu area has tributaries that can be used as energy sources.One of them is Plakat Village, which has the potential for a micro hydro power plant.The PLTMH itself is a source of electricity for the surrounding community which provides many advantages over the limited demand for electricity.This study aims to calculate the initial design of micro hydro power plants on the Enim River.

Material and Method
This research was conducted in Plakat Village, which is located in the Semende Darat Ulu sub-district, Muara Enim Regency, South Sumatra Province, Indonesia.Located between 4° to 6° South Latitude and 104° to 106° East Longitude, this sub-district is located on the Bukit Barisan plateau, Plakat Village is one of the villages in Semende Darat Ulu District.It is located at an altitude above 1,420 m above sea level and is located on one of the Barisan hilltops, at a distance of 20 km from the district capital and 112 km from the district capital, Muara Enim.The area of the village reaches 12,000 ha.This village has the potential for micro hydro power plants by utilizing the Enim River which is an estuary or river headwaters in Plakat Village to be used by Plakat Village residents to meet their daily needs.The analysis stage is carried out by calculating and analyzing the micro-hydro potential in Plakat Village.

Falling water height
The effective fall height is obtained by calculating the energy loss.In the initial planning, it was taken that the energy loss of 10% would be the initial assumption.

Intake channel identification
The intake channel functions to control the water that will flow into the carrier channel.The recapitulation of the intake canal can be seen in Table 1.And the condition of the intake canal can be seen in Figure 3.The condition of the intake

Forebay identification
The forebay functions to control the flow of water in the penstock during load fluctuations, calm the flow of water before it enters the penstock, as well as the final filter for waste and solid particle deposits so that it does not enter the turbine.
The condition of the forebay can be seen in Figure 4.And the recapitulation of the forebay can be seen in Table 2. Keynote: m = meters

Pipe penstock identification
Penstock is the connecting channel between the forebay to the turbine.This pipe is designed to be able to withstand high pressure.The recapitulation of the penstock pipes can be seen in Table 3.And the condition of the penstock pipes can be seen in Figure 5.

Energy loss estimation
In the course of water flowing from the intake door to the penstock, energy loss will occur:   = 0.01 m From several calculations of the energy loss factor in the penstock, it can be seen that the total energy loss is:   =   +   +  +     = 0.06  + 0.01  + 2.2  + 0.01 m   = 2.28  This value is smaller than 10% of the H_effektif is 26.1 m so that this plan can be used.

Analysis of the energy produced
From some of the data obtained, the water flow rate can be calculated as follows: P =  x g x Q x H

Figure 3
Figure 3 The condition of the intake

Figure 4 Table 2
Figure 4 The condition of the forebay

Table 3 Figure 5
Figure 5 The condition of the pipe penstock