One of the main routes to overwhelm the environmental challenges is to switch to sustainable energy sources and hybrid energy conversion plants. In this newly developed model, the integration of the ocean thermal energy conversion-based Reverse osmosis desalination unit and hydrogen generation and compression cycle is simulated and proposed. The combined system generates sustainable power, compressed green hydrogen, and freshwater with integrated subsystems. A detailed thermodynamic simulation and sustainability index assessment are conducted on the various system parameters to determine changes in system efficiency. In this theoretical study, the developed system is motivated by warm sea water temperature which is assumed 35 °C. The thermodynamic modeling, that is energy and exergy performances, and also exergy destruction approaches, is applied to each subsystem and the overall plant by parametric examination method. The consequences expression that the net power generation capacity of this configuration is 150.5 kW, the green hydrogen generation rate is 0.0003011 kgs−1, and also, the freshwater capacity is 4.755 kgs−1. Finally, the developed plant performance ratio is determined as 12.20 % of energetic performance and 24.71 % of exergetic performance.