Evaluation of Micro Hydro Power Plants in Central Java toward Sustainability against Hydrology Condition of Watershed

Land degradation on the upstream of watershed will affect hydrology condition in a way that it will disrupt the sustainability of its existing micro hydro. The purpose of this study is to evaluate micro hydro power plant in central Java toward sustainability against hydrology condition of watershed. This study is using River Regime Coefficient (RRC) approach where hydrology of watershed with coefficient value less than 50 is classified as non-critical, between 50 and 120 is moderate and more than 120 is critical. Result of the study that was done on 33 micro hydro power plants scattered on 9 watersheds is showing that there are 2 power plants on 2 watersheds have hydrology condition in non-critical status (9.09%), 1 power plant on 1 watershed is in between critical and non-critical status (3.03%), 21 power plants on 3 watersheds are in between critical and moderate status (63.64%), 8 power plants on 6 watersheds are in critical status (21.21%) and 1 power plant on 1 watershed is in between moderate and critical status (3.03%).


Introduction
As stated in The Act Number 30 Year 2009 about Electrical-Power that primer energy resource already have been set, which there are in the country and/or from overseas had to be utilized optimally according to National Energy Policy (KEN), that is to guarantee the equipping of electrical power which is sustainable, and furthermore it also set that in utilizing it, new energy resource and renewable energy resource. [1] The policy mention above is in line with the certainty in The Act Number 30 Year 2007 about Energy, that the energy was managed based on the principle of expediency, rationality, efficiency, justice, the increase in added value, sustainability, society welfare, preservation of environmental functions, national resilience, and alignment with emphasis on national capabilities.
Based on Government Regulation Number 79 of the year 2014 about National Energy Policy, the utilization of national energy resources which was directed for electrical power are as follows: Renewable energy resource from energy flow and waterfall, geothermal energy (including small scale/modular), the movement energy and the difference in ocean layer temperature, wind energy, solar energy, biomass and compost, new energy source of solid and gas, gas, coal. [3] Based on Indonesia Republic Number 30 of Year 2007, about energy, the government has to arrange KEN as a manual in national energy management, where the purpose of energy management is for reaching energy independence or ensuring energy supply, to improve energy efficiency, to improve people access toward energy for low income groups, and to ensure environmental sustainability. [2] Changes on KEN according to President Regulation 5 of year 2006 that on 2015 the target is the Energy Mix 2025: Crude oil <20%, Gas >30%, Coal >33%, New Renewable Energy (EBT)>5%, and Energy Elasticity Target <1%. While according to KEN by DEN in 2012 other Principle which will be made as a reference for preparation of KEN is national energy mix target until 2050, national energy mix will be dominated by EBT with the amount of 40 percent which cover water energy, geothermal, trash biomass, Bio-fuels, solar energy, ocean energy, wind energy, and nuclear energy. While for oil, gas, and coal will be at 20 percent range.
As electrical power policy appropriate direction which was organized in RUKD Preparation in Central Java 2015-2020, is in accordance with Central Java Province Government vision and mission that is toward selfcontained and independent Central Java in field of energy. Energy independence based with environmental friendly technology in Central Java, can be implemented by improve people interest and investors to develop and make use of new and renewable energy potential which spread throughout Central Java region, to build facilities and infrastructure which support electrical power system in Central Java, to improve rural electricity grid program and cheap electricity for poor people, implement supply and demand management policies on load side. [4] Rural electricity grid is one of government program which can be used to help people which not yet electrified, so they can enjoy electricity. The electrified village ratio in Central Java are already 100%, but until 2014 hamlet (=village) which not yet electrified in Central Java more or less than 2.096 hamlet.
Electrical energy in Central Java was supplied by power plants which are interconnected in JAMALI System (Java-Madura-Bali) and isolated grid kind power plants. Isolated 11.02%,the rest is Solar Power Plant (PLTS). [5] Given the utilization of new and renewable energy that is most widely used in Central Java as a power plan, is a potential waterfall, then the potential is highly dependent on watershed health, where the watershed (watershed) condition is able to provide all the ecosystem's needs [6], one of which is the continuous availability of water (Hydrological conditions) is good. The problems in the field are the existence of an increasing and uncontrolled development movement, in the upstream basin, so resulting in degradation, and have an impact on quantity and the quality of land resources. [7] In relation there to, monitoring evaluation is required [8], measure the success of changing condition of watershed [9], on location of micro hydro power plants mention above and the result will be used as a guide in the next activity about ongoing implementation [10].
The purpose of this essay is to conduct evaluation of Hydro Micro Power Plant in Central Java towards sustainability against Hydrology Condition of Watershed.

Location of Study and Data Collection
The location reviewed in this paper covers micro hydro power plants as much as 33 location or as much as 9 Watershed, with the boundary of the northern region coordinates x = 399089 y = 9208745, east x = 572138 y = 9212365, south x = 385487 y = 9130271, west x = 269555 y = 9209151.
The data used is the river map along with the river area in Central Java and hydrological data (debit) from the Water Resources and Spatial Development Office in 2014 and 2017.

Methods
The approach of the method used in conducting the study of the hydrological condition of the Watershed according to the location of the study is the River Regime Coefficient (RRC) approach. River Regime Coefficient is comparison between maximum discharge (Qmax) and minimum debit (Qmin) in a Watershed. (1) Where: Qmax (m 3 /sec): the highest annual average daily discharge (Q) Qmin (m 3 /sec): the lowest annual daily discharge (Q).
Classification value of RRC to show the characteristic of Watershed is presented on the following Table: , 0