Abstract: The production of water vapor is controlled in a plant for combusting fine-grained and dustlike solid fuels together with air in a combustion zone of a heat exchanger in the upper region of the combustion zone, a water vapor accumulator, which communicates with the heat exchanger, and a water vapor feed line leading from the water vapor accumulator to a turbine. The rate at which water vapor is produced is continually calculated and is compared with the desired value which is required by the turbine and the rates at which fuel and combustion air are supplied to the combustion zone are adjusted in accordance therewith. The combustion plant may comprise a fluidized bed cooler for cooling a part of the part of the combustion residue. That cooler may comprise a plurality of chambers provided with heat exchangers for an evaporation of feed water or for a super heating of water vapor.