2022 International Electrical Engineering Congress (iEECON) | 978-1-6654-0206-4/22/$31.00 ©2022 IEEE | DOI: 10.1109/iEECON53204.2022.9741607 Spatial Approach on The Isolated Island Variable Renewable Energy Based Electricity Planning B.W. Yudha Electrical Engineering Department School of Electrical Engineering, Telkom University Bandung, Indonesia bayuwirayudha1999@gmail.com F.N. Nursalam Electrical Engineering Department School of Electrical Engineering, Telkom University Bandung, Indonesia nadhilah48@gmail.com S. Sasmono Electrical Engineering Department School of Electrical Engineering, Telkom University Quadran Energi Rekayasa Bandung, Indonesia ssasmono@telkomuniversity.ac.id W. Priharti Electrical Engineering Department School of Electrical Engineering, Telkom University Bandung, Indonesia wpriharti@telkomuniversity.ac.id Y.T. Asidda Electrical Engineering Department School of Electrical Engineering, Telkom University Bandung, Indonesia hanatresnaa@gmail.com Abstract—The isolated island which will be electrified by variable renewable energy needs an optimal electricity planning. Since the solar irradiation or wind velocity is sitespecific, then spatial approach is proposed to meet the objectives. The proposed spatial approach combines spatial demand forecasting and optimal site of the variable renewable energy power plant. The spatial demand forecasting is adapted Lee Willis concept in electricity distribution planning. The spatial matrix score is used to aid the placement of a power plant.. Another electricity grid can be developed based on combination of the center spatial load and optimal site of variable renewable energy power plant (Abstract) Keywords—electricity planning, isolated island, spatial demand forecasting, variable renewable energy power plant I. 1 INTRODUCTION The variable renewable energy source for the power plant is site-specific. Whilst the center of load will be lying in a specific area. The electricity planning has become a challenge as the variable renewable energy does not meet the center of load. The challenge becomes obvious when facing secluded area, such as small islands, due to the highest probability source of variable renewable energy locates far from the limited center of load. The spatial approach may give a solution for electricity planning with massive penetration of variable renewable energy sources in small islands. Since it was first introduced by Van Wormer in 1954 at paper entitled "Some Aspects of the Distribution Area Load Geometry" which was published in Power Apparatus and Systems Volume 73, No. 2, 1954, page 1343-1349, the spatial approach has been continue developed by Lee Willis in electrical demand forecasting for the electrical distribution system. It was then followed by another researcher [4]. Most of the researchers used the spatial approach for spatial demand forecasting by developing a methodology. The model was developed with different variations for short-term demand forecasting by Carreno [1] and Chouw [2] as examples. Tao Hong and Jain introduced another methodology for long-term spatial demand forecasting [3] [6]. Furthermore, S.Sasmono proposed a spatial approach for transmission system planning [5]. Referring to its ability to provide optimal electricity planning in limited islands, the spatial approach is proposed as a methodology to overcome challenging issue where the site-specific variable renewable energy resources reaches offgrid island with limited load center. The research shows the methodology will give an optimal planning as the target of modern power system planning. II. PROBLEM AND METHOD In the isolated island, the load is dispersed. Even there are small spots as load center. On the other hand, the renewable energy variable is a site specific which depends on the energy resources, such as solar irradiation or wind velocity. The optimal power system planning should consider the location of not only the center of load, but also the power plant. Basically, the power plant should be located near the center of load in order to minimize loss as well as to keep the voltage level of the buses. However, the solar irradiation or wind velocity will be different in different sites. The variable renewable energy power plant should be located in the site where the energy resources is maximum. The problem is the location of the power plant may locate far from load center or dispersed load. Thus, it will result in high loss, and the voltage level will be out of allowable range. It is known that there is an insufficient amount of primary energy resource in the secluded island. Therefore, the solar energy and wind velocity can be the only local resources for electricity generation. Since the load is dispersed and the maximum energy resources can be found far from load, then the spatial approach can be implemented to produce optimal power system planning in the secluded island. On the proposing methods, the spatial approach carries out into 4 stages as follows: (1). Spatial demand forecasting, (2). Develop matrix of spatial load and spatial energy resources, (3). Basic design for variable renewable energy generation and (4). Grid modelling. A. Spatial demand forecasting Spatial demand forecasting predicts a small area in which the utility area is divided into small rectangles (grid). Furthermore, the electricity consumption of each small rectangle area is analyzed. The demand forecasting in small island is limited to the island’s size. Thus, the spatial demand forecasting should follow the Gompertz equation as follows. The 2022 International Electrical Engineering Congress (iEECON2022), March 9 - 11, 2022, Khon Kaen, THAILAND 978-1-6654-0206-4/22/$31.00 ©2022 IEEE Authorized licensed use limited to: Universidad Nacional Autonoma De Mexico (UNAM). Downloaded on December 04,2022 at 22:40:43 UTC from IEEE Xplore. Restrictions apply. 2 = (1) Where, y is load in time t, others is parameters. Therefore, the evolution of the island’s land use inside small rectangles in period becomes the parameter. The information regarding the evolution of the island is basically obtained from the government’s document which is a qualitative data. Thus, spatial demand forecasting requires qualitative analysis. Several documents that indicate the direction of development in the observed area of spatial were collected and analyzed. From the qualitative analysis, the evolution or development of the island can be interpretated for period of time. The clustering method was used to classify the type of utility area inside the small rectangle. Each cluster has a symbol or number regarding their type. Each type needs to be separated to tell the difference between clusters such as the difference type of electrical consumption as shown in Table 1. The symbol or number used in land use evolution shows the infrastructure development step by step. TABLE I. III. CASE STUDY Case study of this research was conducted in Rengit island, Bangka Belitung, Indonesia. Rengit island is one of small islands in Belitung which the electricity has not been received, although it is only 12 km from Suge power plant in Belitung Island. Therefore, local people use petrol and generator to provide their electricity needs, although the petrol price is quite expensive for locals. The National Electricity Company (PLN) planned to provide electricity to the island through submarine cable from Belitung main island to Rengit island. The option to use submarine cable seems to be viable. However, Rengit island also has potential to build renewable energy power plant. The island has wind velocity (m/s) of 4.5 m/s at the height (m) of 100 meter and direct normal irradiation (kWh/m2) 1038.2 kWh/m2. The Rengit Island is shown in Fig. 1. In the proposed concept, the Solar PV has planned built electrifying Rengit Island based on the spatial approach. In this case study, the optimal variable renewable energy-based electricity planning becomes the objective of the spatial approach planning. ELECTRICITY CONSUMPTION CLASSIFICATION Land Use Demand Category Number Restricted Area - 0 Low 1 Residential Medium 2 High 3 Low 4 Tourism Industry Medium 5 High 6 Low 7 Medium 8 High 9 Validation of spatial demand forecasting model is done by comparing the real data from government who already forecast the maximum demand for a year. The forecasted demand is also validated to meet the requirements to be considered as reasonable. B. Develop Spatial Matrix Besides the energy consumption, the cluster can be used as the symbol of the land use evolution and symbol of irradiation, wind velocity, or another renewable energy resources inside the rectangle area. The matrix is developed to determine the optimal cluster where the load and the energy resources are maximum. The optimal cluster should be located on variable renewable energy power plant. Fig. 1. Rengit Island IV. SIMULATION RESULTS A. Spatial Demand Forecasting Based on spatial approach proposed by Lee Wilis, The Rengit Island can be divided into 8 grids that is defined as cluster. Therefore, there are 8 spatial clusters in such island which is shown in Fig. 2. C. Grid Modelling The basic design for VRE generation should be developed based on the power and energy balance equation as follows: ∑ =∑ +∑ (2) Where, P = generations, L=load and l = losses. The losses in the basic design are the assumption of losses target. Whilst the grid model should consider the location of the center load in isolated island. The electricity infrastructure will be built based on the location of center load as well as the location of power plant. Fig. 2. Rengit island cluster based on infrastructure development According to Government Development Plan from 2022 to 2027, the development of each cluster is shown in Fig. 3. Cluster 1 and 4 will be the starting point of the developmentby establishing the residential area. Since the Rengit Island has a potential to be tourist destination, then the tourist area will be developed at both cluster 5 in 2023 and cluster 7 in 2025. At least the small The 2022 International Electrical Engineering Congress (iEECON2022), March 9 - 11, 2022, Khon Kaen, THAILAND Authorized licensed use limited to: Universidad Nacional Autonoma De Mexico (UNAM). Downloaded on December 04,2022 at 22:40:43 UTC from IEEE Xplore. Restrictions apply. 3 density industrial area will be developed at both cluster 6 in 2024 and cluster 8 in 2025. Furthermore, the electricity consumption classification in Table 1 is used to define the electricity demand status in every year forecast for each cluster. The data is shown in Fig. 4. = 0,85 1 − −0,0614 , !" 1,36 !" $ %&$'$ TABLE III. (3) RENGIT ISLAND DEMAND PROJECTION Year Demand (Watt) 2022 52320 2023 175461 2024 393624 2025 623946 2026 697988 2027 859148 Fig. 3. Land use prediction with GIS software Fig. 5. Electricity Demand Forecasting 2022-2027 Fig. 4. Rengit island cluster based on electricity consumption The standard electricity used in demand forecasting is shown in Table 2. Thus, the electricity demand can be forecasted. However, the validation should be done in existing year. Since the electricity demand on the existing year is 50 kW, then the electricity demand forecasting 2022 – 2027 is shown in Table III TABLE II. Land Use Residential Fishery Industry Tourist Destination ELECTRICITY CONSUMPTION STANDARD Demand Category Load (Watt/Ha) Lighting 12,000 Lighting 12,000 Cooling 87,000 Lighting 12,000 Cooling 70,000 Toilet 10,000 The Monte Carlo simulation is carried out to consider uncertainty in the demand forecasting. The certainty level of the simulation is 98 % and the results are shown in Table IV and Fig. 6. The certainty approach gives a range of forecasting in the maximum, average, and minimum scenario. TABLE IV. RENGIT ISLAND DEMAND PROJECTION WITH MONTE CARLO Year Minimum (Watt) Maximum (Watt) Mean (Watt) 2022 27818,61 71800,73 47106,44 2023 109830,87 322709,82 203113,16 2024 218618,17 658273,14 417264,08 202 338900,05 871908,74 604546,52 2026 440526,19 977975,48 724410,61 2027 525902,59 1012852,33 787250,6 According to spatial characteristics which must follow the Gompertz Equation, the 2nd validation should be done to determine the electricity demand equation and the maximum demand in the island. The maximum demand is total demand when all the spatial clusters is electrified. The elctricity demand equation and the maximum demand is shown in the following equation: The 2022 International Electrical Engineering Congress (iEECON2022), March 9 - 11, 2022, Khon Kaen, THAILAND Authorized licensed use limited to: Universidad Nacional Autonoma De Mexico (UNAM). Downloaded on December 04,2022 at 22:40:43 UTC from IEEE Xplore. Restrictions apply. 4 Fig. 6. Demand projection graph in range number B. Spatial Matrix The matrix is developed based on 2 parameters, namely solar irradiation and spatial load, and the prediction/forecasting in 2022. The spatial matrix score is shown in Table V. As shown in the Table V, the highest score is in Cluster 1. Therefore, the Solar PV will locate in Cluster 1. TABLE V. Parameter Irradiation (kWh/m2) Score Load Need (kW) Score Total Score SPATIAL MATRIX SCORE Cluster 1 Cluster 2 Cluster 3 Cluster 4 1034.2 1036.9 1032.8 1027.0 3 4 2 1 35 3 16 1 4 7 2 6 3 5 1 2 C. Grid Modelling According to spatial load center, which is shown in Fig, 7, 2 feeders are needed to deliver electricity production from the Solar PV to the load. The single line diagram of the grid which considers the spatial condition of Rengit is shown in Fig. 8. Fig. 8. Single Line Diagram of Rengit Off-Grid System V. The optimal planning of isolated island in which the electricity will be generated should consider the location of the power plant and the center of load. The solar irradiation Is an important aspect to determine the optimal location of Solar PV as variable renewable energy power plant. The research shows that the combination of spatial approach in both spatial demand forecasting and optimum location of Solar PV based on the highest irradiation will result in the optimum electricity planning for isolated island. The robust result of the optimal electricity planning needs grid impact simulation. It will show whether the grid model is able to give a good grid performance to meet the grid code requirements. REFERENCES [1] [2] [3] [4] [5] Fig. 7. Spatial infrastructure CONCLUSIONS [6] Carreno, E. M, Padilha-Fetrin, Leal, A.G “Spatial Electric Load Forecasting Using An Evolutionary Heuristic”, Revista Controle & Automacao, Vol 21 No 4, pp 379 – 387, 2010. Chouw, Mo-Yuen, Zhu, Jinxiang, Tram, Hahn “Application of FuzzyMulti-Objective DecisionMaking in Spatial Load Forecasting“, IEEE Transactionon Power System Vol 13 No. 3, pp1185 – 1189, 1998. Jain, Amit, Jain, M. Babita, “A Novel Hybrid Method for Short Term Load Forecasting using Fuzzy Logic and New Particle Swarm Optimization (NPSO)”, 16th National Power System Conference, pp 132 – 138, 2010. Lee Wilis,“Spatial Electric Load Forecasting 2nd edition”, Marcel Dekker Inc, New York, pp 1 – 5, 2002 Sudarmono Sasmono, Ngapuli Irmea Sinisuka, Mukmin Widyanto Atmopawiro, and Djoko Darwanto, “Macro Demand Spatial Approach (MDSA) at Spatial Demand Forecasting for Transmission System Planning”, International Journal on Electrical Engineering and Informatics - Volume 7, Number 2, June 2015, pp 193-206 Tao Hong, “Long-Term Spatial Load Forecasting”, Thesis Manuscript, North Carolina State University, 13 – 70, 2008. The 2022 International Electrical Engineering Congress (iEECON2022), March 9 - 11, 2022, Khon Kaen, THAILAND Authorized licensed use limited to: Universidad Nacional Autonoma De Mexico (UNAM). Downloaded on December 04,2022 at 22:40:43 UTC from IEEE Xplore. Restrictions apply.