**5. Conclusions**

The aim of the article was to first see how Cuban policy goal with 24% penetration of renewable sources is possible. The electrical system of Isla de la Juventud has important similarities with the electrical system of Cuba and the economic, social and energy related data used by the model allowed analysis of different factors to showcase results that serve as an important evidence in the context of Cuba.

Secondly, geographical, economic and social conditions make Isla de la Juventud an ideal test scenario for Cuba, and the results of this work will help to understand the path that must be followed to achieve a power system with 100% of generation based on renewable energy, obtain maximum reduction on the use of fossil fuel and greenhouse gas emissions.

The use of the LINDA model allowed construction of different scenarios for the introduction of renewable sources in Isla de la Juventud. In the analyzed scenarios, solar energy (19.2 MW of installed capacity) coupled with energy storage systems play a fundamental role in meeting the demand and allowing up to 38% penetration from renewable

sources in RENES reducing greenhouse gas emissions to 78.2 Mton of CO2 equivalent. If wind energy and biofuel are added to the generation mix, it is possible to achieve energy independence (also from fossil fuels with 100% RES based electric system) and reduce the emission of greenhouse gases only 13.9 Mton CO2 equivalent per year. Both scenarios show, in comparison with the base year 2019 of with 120 GWh of production and 82 Mton CO2 equivalent, a significant decrease in the emissions especially as the future estimated production increases to 129% in RENES and 175% in MAXRES compared to base year.

These results show transitioning towards sustainable energy and electric power systems is evidently possible in Cuba with the results shown in RENES and MAXRES scenarios. The analysis of the electrical power system for the different sectors of the economy offers the possibility to model the energy mix in the long term as well as to see the impact on the emissions and the influence of new installed RES capacities in Isla de la Juventud. Here open source tools such as Long-range Integrated Development Analysis (LINDA) can provide critical information on the different development trajectories.

The current policy aims are within reach and even exceeding the targets is also well within realism. This, however, requires robust analysis regarding the technical and economic possibilities in Cuba. Until recently, access to resources, mainly equipment and financing, has by far been the most limiting factor. Furthermore, enabling aspects such as legal and regulatory framework, investment incentives, pricing mechanisms and motivation of stakeholders are crucially important in meeting the challenge in moving towards 100% RES based electricity system. Drafting a clear roadmap on how to realize the transition is thus a priority that should be addressed adequately.

**Author Contributions:** Conceptualization, E.A.A., M.K., A.S.F.; methodology, software and validation E.A.A., M.K., A.S.F., J.L.; formal analysis, E.A.A., M.K., J.L.; investigation, E.A.A., M.K., A.S.F., J.L.; resources, E.A.A., M.K., A.S.F., M.L.F.S.d.R., J.L.; data curation, E.A.A., M.K., A.S.F., J.L.; writing—original draft preparation, E.A.A., M.K.; writing—review and editing, E.A.A., M.K., A.S.F., M.L.F.S.d.R., J.L.; visualization, E.A.A., M.K.; supervision, A.S.F., M.L.F.S.d.R., R.A.P., J.L.; project administration, J.L.; funding acquisition, J.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** The authors wish to thank the Academy of Finland for funding the IRIS project (Integration of renewable intermittent sources in the power system (research project number 320229).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy and sensitive nature of the data.

**Conflicts of Interest:** The authors declare no conflict of interest.
