# Optimizing Sustainable Energy Transitions in Small Isolated Grids Using Multi-Criteria Approaches
## 3 Materials and Methods
### EnergyPLAN Software  
In the last few years, several estimation methods have been defined and used in various studies to evaluate electricity demand and generation in different types of scenarios with varying levels of GHG emissions. For example, as particular applications of different code simulation tools, [PERSON] et al. [14] presented a forecast for Gran Canaria for 2040 in a scenario of total decarbonization of the economy using HOMER software. [PERSON] et al. [31] performed several forecast simulations for the South Tyrol region using EnergyPLAN software. [PERSON] et al. [32] simulated different scenarios varying the renewable penetration on the island of S. Vicente in Cape Verde using the H2 RES tool, and [PERSON] et al. [49] conducted a long-term analysis of Pakistan using the LEAP tool. Other research works compile reviews of different energy simulation tools. [PERSON] and [PERSON] [33] reviewed many energy simulation tools for the United Kingdom. Similarly, [PERSON] et al. [50] reviewed the most used tools for energy and electricity systems employing highly renewable resources, and [PERSON] et al. presented a review of existing simulation tools for energy system scenarios applied at the island level [34].  
Based on the previous comments, it has been considered that several tools are useful for the objective pursued in the current work. In this context, the widely known tool EnergyPLAN has been used [51]. EnergyPLAN is a broadly used tool for designing energy systems, mainly for future sustainable energy solutions [36]. The software is a deterministic input/output tool that simulates the operation of energy systems from the local to the global level, making balances even of the hourly or lower order. The scientific community widely uses this software for various applications. The primary purpose of EnergyPLAN is to analyze the energy, environmental and economic effect of different energy strategies by modeling a variety of options that can be compared, rather than optimizing a single solution [52]. It focuses on modeling the future energy system and how it will operate. For instance, additional criteria can be considered, such as the need for less installed power, minimizing energy wastage, the weighted combination of several factors, penalties for land occupation or visual pollution, etc.  
EnergyPLAN is a simulation tool for analyzing energy system scenarios without being constrained by cost minimization, distinguishing it from other calculation tools. It operates through an energy balance at defined time steps, typically hourly, comparing energy demand with available generation and optimizing generator and storage operation [36,53]. The economic analysis seeks a balance between generation and storage sizing to minimize costs while ensuring reliability. Using 2023 economic data, the methodology is tested in two scenarios: one replicating the current system and another applying multi-criteria optimization to transition toward a fully renewable system while maintaining 100% reliability in isolated grids. A precise methodology was followed to perform the computer code estimates, which included a detailed introduction of the necessary input information and an outline of the steps used, as shown in Figure 7. The required input dataincludes annual information on energy demand or, for future estimates, their forecasts; technical and cost information on the generation system to be considered (in the current study, wind and photovoltaic power plants); technical and cost information on the storage system (mega-batteries and reversible pumping); the energy resources available for each generation system (wind and solar resources available at the selected sites); and additional economic data (such as the annual interest rate and the project's useful life).