International Journal of Marine Engineering Innovation and Research, Vol. 5(4), Dec. 2020. 291-299 (pISSN: 2541-5972, eISSN: 2548-1479) 291 Economic Dispatch Analysis of Hybrid Power Plant System in Islands Area Based on Linear Programming Method Rusdianto 1 , Eddy Setyo Koenhardono 2 , Juniarko Prananda 3 (Received: 03 August 2019 / Revised: 15 December 2020 / Accepted: 20 December 2020) Abstract– the increase in electricity demand in Selatpanjang, Meranti Island Regency, Riau continues to occur. However, the availability of diesel fuel types is increasingly scarce and the price is increasingly expensive. Therefore, another generator is needed, namely a relatively cheap coal-fired power plant and the availability of coal reserves in the Sumatran region. One of the problems in the economic operation of a generating system is economics dispatch, which is how to obtain minimum operating costs while meeting existing and reliable limits. For this reason, an economic dispatch analysis is needed for the optimal generating system by using the linear programming method. This economic dispatch analysis uses operational cost as a parameter and is done by using software assistance in the form of Matlab. Based on the results of loading with the same variation, the power generation based on economic dispatch calculations has an average load factor smaller than the average load factor based on unit commitment improvement calculations. Thus, the generation with economic dispatch has a higher specific fuel consumption (g/KWH) than the unit commitment improvement so that the fuel consumption price is issued higher. Keywords–economic dispatch, unit commitment improvement, linear programming, load factor. I. INTRODUCTION 1 Electricity needs in the Selatpanjang area, Meranti Island Regency, Riau continue to increase with an average of 6.54% per year and until now only supplied by Diesel Power Plants (PLTD) [1]. At the same time, the availability of diesel fuel types is increasingly scarce and the price is relatively expensive. Therefore, the use of alternative power plants is needed so that electricity needs in the Selatpanjang region, Meranti Island Regency, Riau can be fulfilled. The alternative generator is considered relevant if applied in the Selatpanjang area, namely coal- fired Steam Power Plant (PLTU). This is due to the availability of coal resources in the Sumatran region in 2017, which is 36.72% or 45,969.24 million tons of total national coal resources, while coal reserves are around 40.88% or 9,909.1 million tons [2]. Plus the price of coal fuel is lower than natural gas in the interest of electricity, which is USD 70 / metric ton with a calorie level of 6,322 kcal/kg GAR, equivalent to USD 3.08 / MMBtu, while the natural gas price of the region 2 (southeast Sumatra and south), which is USD 6.05 / MMBtu [3]. The limited availability and high prices of fossil fuels for this need to be carried out by the operating system management of the generating system. Where one of the problems in the economic operation of a power plant is economics dispatch, which is how to get a minimum operating cost while still meeting existing and reliable limits [4-9]. To solve all these problems, it is necessary to do an economic dispatch analysis for generating systems Rusdaianto, Department of Marine Engineering Institut Teknologi Sepuluh Nopember Surabaya, 60111, Indonesia. Email: rusdianto163@gmail.com Eddy Setyo Koenhardono, Department of Marine Engineering Institut Teknologi Sepuluh Nopember Surabaya, 60111, Indonesia. Email: eddy- k@its.ac.id Juniarko Prananda, Department of Marine Engineering Institut Teknologi Sepuluh Nopember ITS Surabaya, 60111, Indonesia. Email: juniarko.prananda@gmail.com that are suitable for the Selatpanjang, Meranti Islands Regency, Riau. II. METHOD In this study, economic dispatch analysis was carried out using linear programming methods and assisted by the Matlab application. The output of linear programming is in the form of incremental power. A. Economic Dispatch Economic Dispatch is the process of determining the output power produced by a unit or system unit to supply the specified load by minimizing the total fuel cost [4-9]. The amount of the total power produced by the power generation system must be the same as the load demand. In simplified cases, transmission losses are ignored. This makes the task procedure solution easier. The practice, transmission losses must be considered [4]. Figure 1 shows the configuration of this system which consists of N power generating units connected to a single busbar that supplies the Pload electric load. The input for each unit, shown as Fi, represents the cost rate of unit i. The output of each unit, Pi, is the electrical power produced by unit I itself. The level of the total cost of this system is the sum of the costs of each unit. 1) The cost function The fuel cost function is usually estimated as a quadratic equation, this is the objective function [5]:   =∑ (  +    +     2 )  =1 (1) Where: F = fuel cost N = total number of units