<p>In the context of accelerating technological development and the global shift toward sustainable and low-carbon energy systems, advanced cogeneration technologies that integrate renewable resources have gained increasing importance. This study proposes an innovative geothermal-driven cogeneration system designed for the simultaneous production of hydrogen, oxygen, and freshwater—three key resources for future clean energy infrastructure. The proposed system comprises a dual-pressure organic Rankine cycle (ORC), a reverse osmosis (RO) desalination unit, and a proton exchange membrane (PEM) electrolyzer. A multi-objective optimization using a Genetic Algorithm was conducted to minimize the total exergy destruction cost rate while maximizing freshwater production. Comprehensive energy, exergy, economic, and exergoeconomic evaluations were performed. The optimum configuration achieved an exergy efficiency of 23.80%, with daily production rates of 1731.5 kg of hydrogen, 1374.3 kg of oxygen, and 3636 m³ of freshwater. The ORC unit exhibited the highest exergy destruction, responsible for 61% of the total loss. Although the PEM electrolyzer contributed less to the overall exergy destruction, it accounted for the highest cost rate of exergy destruction at 65% of the system total. Exergoeconomic results estimated the production costs of hydrogen–oxygen and freshwater at 3.92 $/kg and 0.28 $/m³, respectively. Finally, the proposed configuration demonstrated strong economic viability, with an ROI of 648%, an IRR of 17.47%, a positive NPV of 1.93 × 10⁷ $ and a payback period of 8 years, indicating a favorable return on investment.</p>