NOVELTY - A carbonization device (15) provided in sewage treatment installations (11a-11n) produces a carbonized material from sewage sludge. A fuel management system (14) notifies the thermal power plant suitable for receiving the carbonized material, among the thermal power plants (12a-12m), based on determined characteristic of the carbonized material of each installation and the coal used in each plant.    USE - Used as a biomass fuel supply system used to supply biomass fuel obtained by carbonization of sewage sludge to thermal power plants used to generate electric power.    ADVANTAGE - Biomass fuel of suitable quantity, and biomass fuel of quality suitable for mixed combustion with coal in the particular thermal power plant, is supplied based on the evaluated characteristic of biomass fuel and coal. Effective usage of biomass fuel is achieved, while reduction in the usage amount of fossil fuels is achieved.    DETAILED DESCRIPTION - The carbonized material is produced by solidification and carbonization of sewage sludge. The management system estimates the environmental impact produced during the combustion of a mixed fuel comprising a mixture of carbonized material and coal. A fuel characteristic diagnostic unit judges the fuel utilization property by a boiler. Ash generation amount during combustion of the mixed fuel is estimated. The generation amount of the carbonized material in each installation, and the quantity of carbonized material to be stored in each power plant are collated. A storage-quantity management unit judges the acceptance property of the carbonized material in each power plant, and notifies the power plant capable of receiving the carbonized material from the treatment installation. The power plant produce electric power by driving a turbine by the steam produced by combustion of coal.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of the biomass fuel supply system. (Drawing includes non-English language text).    sewage treatment installations (11a-11n)    thermal power plants (12a-12m)    fuel management system (14)    carbonization device (15)