NOVELTY - A carbonaceous feedstock and greenhouse gas stream (B) are converted to synthesis gas comprising carbon monoxide and hydrogen. Portion of synthesis gas is electrochemically oxidized in half-cell to carbon dioxide and water. The carbon dioxide is recovered to serve as 20% or more of stream (B) used in conversion. Oxygen-containing gas in half-cell is electrochemically reduced, to produce electrical energy.    USE - For converting carbonaceous feedstock into electrical energy used in electric power producing fossil fuel plant, petroleum refinery and petrochemical plant.    ADVANTAGE - The method eliminates the need of expensive catalyst and high pressure operation. The process avoids difficult path of attempting to strip and capture carbon dioxide from stack gases, and uses unique gasification technology. The method enables to recycle pure carbon dioxide to the gasifier and maintains high hydrogen content in the gasifier. The carbonaceous feedstock is converted into useful hydrocarbon products and high efficiency electric power without producing carbon dioxide or greenhouse gas emission. Thus, wide variety of waste stream is used as feed material.    DETAILED DESCRIPTION - A carbonaceous feedstock of coal, hydrocarbon oil, natural gas, petroleum coke, oil shale, carbonaceous-containing waste oil, carbonaceous-containing hazardous waste and/or carbonaceous-containing medical waste, and a greenhouse gas stream in a gasification unit are converted into synthesis gas comprising carbon monoxide and hydrogen. The gasification unit is a non-catalytic high temperature, gas-phase reactor (12) operating at conditions to achieve a gas exit temperature of 700-1600degreesC. Portion(s) of the synthesis gas is electrochemically oxidized in a half-cell (I) of a fuel cell (26) (anode) to a half-cell (I) exit gas comprising carbon dioxide and water. The carbon dioxide is recovered to serve as 20% or more of greenhouse gas stream used in conversion. An oxygen-containing gas in a half-cell (II) of the fuel cell (cathode) completing the circuit is electrochemically reduced, to produce electrical energy without producing unwanted greenhouse gas emission.    An INDEPENDENT CLAIM is included for system for converting carbonaceous feedstock into energy without producing unwanted greenhouse gas emission.    DESCRIPTION OF DRAWING(S) - The figure shows schematic process flow diagram of process and system for converting carbonaceous feedstock into electrical energy.    gas phase reactor (12)    outlet line (18)    flow lines (20,22)    fuel cell (26)    Fischer-Tropsch catalytic reactor (30)