To meet the carbon-free energy and water demand requirements by Europe, this work has proposed an interconnected and integrated-energy-water-hydrogen (IEWH) system. Typically these systems are generally uncoupled, however, they may be interconnected and can be operated to provide green energy and water with reduced carbon footprints. This work has used power, water, and co-generation facilities to generate power, water, and hydrogen through the electrolysis process. Co-generation and power plants meet the water and energy demand for the electrolysis process. We propose an initial formulation of the mathematical models and objective functions of power, water, co-generation, and electrolysis facilities. The final optimization problem subject to generation, transmission, and process constraints is formulated as a nonlinear programming problem, which is solved using the CONOPT solver. Finally, the developed model is tested on a test case comprised of IEEE 30 standard bus and Hanoi water distributions, (UK), to validate the achievements in cost and CO2 reduction. Simulation results show that integration of hydrogen facilities to produce the electricity power significantly reduces the carbon emissions. (C) 2022 IEEE.