# Long-Term Renewable Energy Planning in the Indonesian Context: A Lombok Island Study Case
## 2 Materials and Methods  
From a long-term investment point of view, community microgrid planning and operation will need to ensure resource allocation efficiency, facilitated by appropriate revenue flows, to achieve optimum outcomes for all stakeholders, including the community, investors, and providers [15]. The optimal planning of the interconnected network of multi-microgrids is discussed in [16]. In this reference, interconnection planning will enhance the reliability and economic operation of a community of microgrids. The proposed approach will apply to the optimal planning of interconnection among microgrids with variable renewable energy sources. The optimal planning takes into account various factors, including economics, reliability, variability of renewables, network- and resource-based uncertainties, and adaptability to accommodate the prevailing operating concerns.  
The major goal of this paper is to create the best planning tools for community MGs to supply essential loads during natural disasters (NDs), with a focus on essential loads like hospitals and hotels. The optimisation that seeks to reduce total cost is also a secondary goal. Finally, we'll talk about how to achieve two results. The first is choosing a location to link the MG to the grid, and the second is showcasing the MG's generation capacity for the service to provide the system's vital loads during natural disasters. On the other hand, the problem's inputs call for the network topology, data on the load profile, and a projection of the load growth rate. Some of the constraints [4] that the problem must address are as follows:  
Power Flow Constraints: Load flow necessitates the estimation of electrical parameters like bus voltages and line currents. Also, the MG assists in supplying the important loads modelled by the power islanding. To enable the evaluations above, the set of power equations should, therefore, be solved as precisely as feasible.  
Operational Constraints: Equipment like buses, lines, and generators must operate safely under specified parameters in order to remain within safe operating limits. The voltage of buses should be kept as close to 1 p.u. as feasible (often 0.05 p.u.), and the loading of the branches linked to the transformer should not exceed the capacity of the transformer. The current flowing through a line should not exceed its thermal limit. These restrictions are included in the restrictions of this category, along with restrictions on storage capacity, power balance (supply and load), and limits on MG generation.  
Topological Constraints: The distribution networks (DN) are often radial networks, and the radial network helps to ensure that the protective conditions operate as they should. Additionally, it is important to provide affordable, safe, and secure communication between MGs, lines, buses, and generation units.  
The main objective of this section is to focus on the long-term planning of MGs. To successfully accomplish this goal, it is essential to determine the load growth rate that is applied to the baseline load. Understanding the rate at which the load is expected to increase over time is crucial for accurately forecasting future energy demands and effectively planning the capacity and expansion of MGs in the long term. By considering the load growth rate in the planning process, it becomes possible to ensure that the MGs are designed to meet the anticipated increase in energy demands and maintain reliable and efficient operation over the long term.