NOVELTY - The process comprises producing electricity by combustion of hydrocarbon fuel (1) with an oxidant (2) comprising oxygen produced by an electrolysis unit, where the combustion produces a carbon dioxide (CO2) rich stream, increasing a pressure of the CO2 rich stream by compression and cooling steps, treating the CO2 rich stream to remove a part of the dust, nitrogen oxides and sulfur oxides, injecting CO2 rich stream into a saline aquifer (6) and evacuating a saline water aquifer (SA), and introducing saline water in the electrolysis unit.    USE - The process is useful for production of electricity and hydrogen such as coal, oil or gas from hydrocarbon fuel including natural gas, liquid fuel, coal, petroleum coke and wood, where the electricity and hydrogen are useful in vehicle and in thermal power plant.    ADVANTAGE - The process ensures economical production of electricity and hydrogen with reduced carbon dioxide emission and less energy consumption.    DETAILED DESCRIPTION - The process comprises producing electricity by combustion of hydrocarbon fuel (1) with an oxidant (2) comprising oxygen produced by an electrolysis unit, where the combustion produces a carbon dioxide (CO2) rich stream, increasing a pressure of the CO2 rich stream by compression and cooling steps, treating the CO2 rich stream to remove a part of the dust, nitrogen oxides and sulfur oxides, injecting CO2 rich stream into a saline aquifer (6) and evacuating a saline water aquifer (SA), and introducing saline water in the electrolysis unit that decomposes saline water into oxygen and hydrogen by an electric current. The electric current used in the electrolysis unit is partly produced in the step of production of electricity. The hydrogen is combusted to produce electricity that is partially implemented in the electrolysis unit. The electrolysis unit is supplied with saline water and an addition of water.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a oxy-combustion unit.    Fuel (1)    Oxidant (2)    Conduit (3)    Saline water (6)    Compression unit (C)    Surface aquifer. (SA)