# Optimizing Sustainable Energy Transitions in Small Isolated Grids Using Multi-Criteria Approaches
## 4 Results and Discussion
### Performance of the Optimized Generation System  
The optimization algorithm has produced an adjusted scenario based on the hourly wind speed and solar irradiance data for the year 2023. This year preserves a slightly increasing tendency in electric energy consumption, while solar irradiance has been fairly constant over the years, even though wind is not as constant, representing the smallest contribution of recent years. In fact, as shown in Table 1, there is some variability between renewable production in different years. Consequently, as outlined previously, 2023 was the worst-performing year for the wind-hydro plant, with only 35% of renewable generation, while in 2018, the wind-hydro plant provided over half of the required energy to the grid, specifically more than 56% of renewable generation, which has been the most favorable year. The year 2017 is a typical example of a year in which renewable power plants contributed almost half of the energy to the grid, particularly almost 47% of renewable generation. The optimized energy setup is exposed to the wind speed and solar irradiance of the years 2018 and 2017 to analyze the performance of the 2023 electric demand. Consequently, the performance that the proposed system would have under the different climatic conditions that have been observed over the last few years should be analyzed in order to provide predictions of how the system would perform under the different climatic conditions that have historically occurred on the island. As mentioned in Section 4.1, data from the last 20 years have been analyzed to determine the hourly distribution of renewable resources, i.e., sun and wind, for a typical year (2017), a favorable year (2018) and an unfavorable year (2023). Obviously, as it is an isolated system, the generation mix must be able to cover the demand in the adverse years; so, the system optimization analysis was justified for this adverse year. But precisely because of this variability, it is interesting to analyze the performance of the system for those typical years or even for those more favorable years. To this end, Figure 13 shows how the system would perform the demand coverage for these situations. We began by highlighting how a system that is near its limits covers the demand during the winter months, especially in December, when it performs under adverse conditions for renewable resources (Figure 12), while the same generation mix easily covers demand when annual environmental conditions of an average year are considered, and how this margin of coverage becomes even more pronounced for favorable years (Figure 13). Additionally, as shown in the above-mentioned figures, it should be noted that diesel is used much less in a favorable year, has intermediate use in an average year, and is used much more in an unfavorable year, with usage spiking during the fall-winter months, from October to December. Another aspect to highlight is that in average and favorable years, there is less use of pumped storage, as the rest of the system is capable of covering the demand on its own most of the time (Figure 13). It is also important to note that solar power remains much more consistent across all three scenarios, with the lowest generation in winter and the highest from April to approximately October. In the same vein, when comparing surpluses, there are practically zero excesses for 2023 (since diesel generation, being a dispatchable source, adjusts to demand) compared to appreciable values for a year with average renewable resources, in almost all months, with lower values in the winter months due to the poorer performance of renewable generation. In contrast, a favorable meteorological year shows even higher surplus values. However, due to the intrinsically variable nature of these renewable resources, the most adverse month in the average year presented is not December but October (a situation that is not uncommon in the Canary Islands, as this month is prone to having lower winds).