Facilitating high-RES (Renewable Energy Resources) penetration via integrated resource management is considered a promising strategy on different islands worldwide. For this work, the Portuguese island of Porto Santo is established as a test bench using actual data from the island. Given its geographical condition and energy needs, integrating the management of different resources (namely, the electric power grid with the water supply system, intensive in-land transportation electrification, and the energy storage applications) is analyzed by this work to achieve a power grid relying entirely on RES. The energy storage utilization and the purposeful manipulations in demand patterns have been perceived as instruments to reduce RES availability and consumption mismatch. Electric Vehicles (EV) could be perceived as a reliable alternative to centralized storage systems, acting either as a load or power resource (generator), providing the required flexibility for power systems to uptake the increased RES and maintaining the balance of supply and demand. This means that EVs could contribute to greening both the power system and the transport sectors. Hence, the impact of the EVs’ penetration level on the island was assessed through a gradual increase in the EVs’ total number (from 0 to a fleet containing 2500 vehicles). Furthermore, a collaboration between the water supply (seawater desalination) and the energy sector is proposed. The obtained results revealed that the optimized management of resources could significantly help the overall energy system (power grid) to rely only on RES (solar and wind energies). The curtailments decreased relatively (maximizing the RES share), while the polluter conventional power plant remained off over the simulation periods.