NOVELTY - The method comprises: (a) performing plasma gasification of chlorine-containing combustible stream to generate a hot chlorine-containing synthesis gas; (b) generating a saturated first high pressure steam using heat from the hot chlorine-containing synthesis gas; (c) removing a significant portion of the chlorine from the chlorine-containing synthesis gas to produce a low- chlorine synthesis gas; and (d) partially converting mechanical energy to electric power in a first power generator using the low-chlorine synthesis gas as a fuel for a gas turbine (106).    USE - The method is useful for generating electric power from a chlorine-containing combustible stream during a period of peak power demand, where the chlorine-containing combustible stream is a waste stream including a refused derived fuel stream that is derived from a solid waste stream such as a municipal solid waste stream (all claimed).    ADVANTAGE - The method is capable of economically converting the chlorine-containing solid waste into the electric power with high efficiency and yield and without the need of large external source of low-chlorine-containing fuel.    DETAILED DESCRIPTION - The method comprises: (a) performing plasma gasification of chlorine-containing combustible stream to generate a hot chlorine-containing synthesis gas; (b) generating a saturated first high pressure steam using heat from the hot chlorine-containing synthesis gas; (c) removing a significant portion of the chlorine from the chlorine-containing synthesis gas to produce a low- chlorine synthesis gas; (d) partially converting mechanical energy to electric power in a first power generator using the low-chlorine synthesis gas as a fuel for a gas turbine (106); (e) further increasing the temperature of the high pressure steam in a superheating step using the heat from the hot exhaust gasses from the gas turbine; and (f) feeding the superheated steam to a steam turbine for partially converting mechanical energy to electric power in a second power generator. The temperature of the first high pressure steam is 200 degrees C or 300 degrees C. The step (a) is a single stage or a two stage gasification step. The chlorine-containing combustible stream contains 5 ppm by volume of chlorine expressed as hydrogen chloride. The method further comprises: (g) generating a second high pressure steam using the heat from the hot exhaust gasses from the gas turbine. The second high pressure steam is flowed to the steam turbine of which a part of the mechanical energy is converted to electric power. The temperature of the high pressure steam from the step (g) is further increased by superheating before it is flowed to the steam turbine. The high pressure steam from the step (g) is combined with the high pressure steam from the step (b) before being flowed to the same steam turbine, and is superheated together with the high pressure steam from step (b) in a superheater. The metal skin temperatures in the high pressure steam generator of the step (b) and/or of the step (g), if present, are 350 degrees C or 450 degrees C. The superheated steam from the step (e) has a temperature of 290 degrees C. The metal skin temperatures in the steam superheater of step (e) are 400-655 degrees C. The gas turbine and the steam turbine drive in a common power generator or a different power generator. The synthesis gas is combusted in the gas turbine using air as the oxygen carrier and/or with an oxygen-containing gas, which is richer in oxygen than regular air. The exhaust gasses from the gas turbine have a temperature of 400-600 degrees C. The hot exhaust gasses from the gas turbine are heated with a combustion of low-chlorine synthesis gas from step (c) and/or heated using the excess oxygen, which is present in the hot exhaust gasses from the gas turbine. The steam turbine has two stages and a part of the exhaust steam of the higher pressure turbine stage is further heated before it is used to drive the lower pressure turbine stage. The steam turbine lowest pressure exhaust is present at a pressure of 0.7 bar absolute (bara). The exhaust steam of the steam turbine is condensed to form a condensate, which is partly recycled to the high pressure steam generation in the step (b) and/or the high pressure steam generation in the step (e). The chlorine-containing synthesis gas is cooled before the step (c). The chlorine is removed in step (c) by passing the synthesis gas through a system including a wet scrubbing system, a semi-wet scrubbing system, a flash dry system and/or a dry adsorption system.    DESCRIPTION OF DRAWING(S) - The diagram shows a flow chart of a method for generating electric power from a chlorine-containing combustible stream.    First steam boiler (101)    Cooler (103)    Syngas compressor (105)    Gas turbine (106)    Second steam boiler. (108)