NOVELTY - The system has a first stage of membrane separators (15) separating carbon dioxide from other gases in exhaust gas. A second stage of membrane separators (16) produces carbon dioxide permeate gas with purity greater than 90 percent. A carbon dioxide gas compressor (17b) receives the permeate gas. Each membrane in the first stage has permeance greater than 800 gas permeance units and carbon dioxide to nitrogen selectivity of greater than 10. Each membrane in the second stage has permeance greater than 10 gas permeance units and selectivity greater than 30.    USE - System for separation and non-polluting disposal of carbon dioxide derived from exhaust of burning fossil fuel. Used in a system for production of electrical energy from natural gas fuel (claimed).    ADVANTAGE - The separating and non-polluting disposal system uses natural gas or coal to separate carbon dioxide from exhaust gas and sequester the carbon dioxide, realizing profits of over 25 million dollars for the coal burning facility. The system operates even at night and even in absence of wind or solar power, and avoids issues of meltdown, radiation danger or long term storage associated with nuclear power. The system can be retrofitted with existing coal burning power plant or gas burning plant. By using a cascade system with different membranes and pressures at each stage, the system is above a Robeson's upper bound.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a method for the separation and non-polluting disposal of carbon dioxide in the exhaust from the burning of fossil fuel;    (2) a system for production of electrical energy from natural gas fuel with separation and non-polluting disposal of carbon dioxide; and    (3) a method for production of electrical energy from natural gas fuel with the separation and non-polluting disposal of carbon dioxide.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic diagram of a system for separation and non-polluting disposal of carbon dioxide.    Heat exchange boiler (12)    First stage of membrane separators (15)    Second stage of membrane separators (16)    Carbon dioxide gas compressor (17b)    Generator (18)