NOVELTY - Energy producing system includes a semi-permeable barrier separating a solvent chamber from a pressure chamber. The barrier is permeable to solvent molecules and impermeable to solute molecules. The solvent molecules effuse across the semi-permeable barrier into the solute solution of the closed pressure chamber to increase the pressure of the chamber to generate energy in the form of hydrostatic pressure. A mechanical device (70) connected to the system may include an alternator, gear, flywheel, hydraulic motor, etc.    USE - For producing energy such as electricity; producing and maintaining steady state, high pressure; and producing vacuum (claimed), for use in power supply system.    ADVANTAGE - The novel system provides efficient transforming kinetic energy from Brownian motion, through the diffusion of solvent or gas molecules, into mechanical work. It consumes fuel or other form of generated energy instead of extracting ambient heat energy. It does not create chemical reactions inside or outer of the system and provides no particulate, gas or heat emissions.    DETAILED DESCRIPTION - Energy producing system (10) comprises a solvent chamber (20) for holding a solvent solution, a pressure chamber (30) for holding a solute solution, and a semi-permeable barrier (40) separating the solvent chamber from the pressure chamber. The barrier is permeable to solvent molecules and impermeable to solute molecules. The solvent molecules effuse across the semi-permeable barrier into the solute solution of the closed pressure chamber to increase the pressure of the pressure chamber thus generating energy in the form of hydrostatic pressure.    INDEPENDENT CLAIMS are also included for:    (1) A method of producing energy comprising providing the energy generating system, filling the solvent chamber with a solvent, filling the pressure chamber with a solute solution comprising a solute and solvent, flowing solvent from the solvent chamber to the membrane, so that solvent molecules effuse across the semi-permeable membrane into the solute solution to increase the pressure in the pressure chamber, and converting the increased pressure in the pressure chamber to energy;    (2) A method for producing and maintaining a steady state, high pressure;    (3) A method of producing a vacuum; and    (4) A membrane cartridge for separating a pressure chamber from a solvent chamber in a system for producing energy comprising a first layer comprising a material through which solvent molecules can pass while preventing passage of solute molecules, a second layer comprising a material through which solvent molecules can pass while preventing passage of solute molecules, and a support within a pocket of a sack. The second layer is connected to the first layer to form the sack having the pocket.    DESCRIPTION OF DRAWING(S) - The figure shows a power supply system including the above energy generating system.    Energy producing system (10)    Solvent chamber (20)    Pressure chamber (30)    Permeable barrier (40)    Mechanical device (70)    Power supply system (100)