An apparatus and method for controlling the power generation of a distributed power generation system including a plurality of small power plants. The apparatus has a first communication interface unit to receive measured values of the instantaneous power generated by the small power plants, and to transmit to each of the small power plants, information relating to the individual power control thereof. A second communication interface unit receives, from a production control center, power values specified as a function of the instantaneous load of the power supply system. A central data processing unit determines the aggregate instantaneous power of the distributed power generation system based on the measured power values, determines the difference between the power specified by the production control center and the aggregate instantaneous power of the system, and generates power control information for each of said small power plants as a function of said power difference.