Decarbonisation in the generation of electricity is necessary to reduce fossil fuel consumption, the pollution emitted and to meet the Energy Technology Perspectives 2 ¿C Scenario (2DS) targets. Small islands are not exempt from this target, so this study’s emphasis is placed on a 50-50 target: to reduce the fossil fuel consumption through electricity generation from Renewable Energy Sources (RES) to cover 50% of all electric demand by 2050 on small islands. Using Cozumel Island, Mexico, as a case study, this analysis will be based on three factors: economical, technical, and land-use possibilities of integrating Renewable Energy Technologies (RETs) into the existing electrical grid. This analysis is made through long-term statistical models. A deterministic methodology is used to perform time-series simulations. The selection of the best system was made on the basis of a Dimensional Statistical Variable (DSV) through primary and secondary category rankings. The presented methodology determines the best systems for capturing the initial capital cost and competitiveness of this new proposal compared with the current system of electricity generation on the Island, and can be applied to small islands as well. According to the results, all systems proposed are able to completely satisfy the renewable electricity needed by 2050 in all scenarios. From the 12 system proposals that were compared, two systems, System 2 and System 7, were chosen as eligible systems to be installed. The Levelized Cost of Energy (LCOE) result for System 2 was 0.2518 US$/kWh and for System 7 was 0.2265 US$/kWh by 2018 in the Base Scenario. Meanwhile, the Internal Rate of Return (IRR) value fluctuated from 17.2% for System 2 to 31% for System 7.