TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred System : Another slurry production and storage system comprises a reaction means for producing a slurry fuel from solid waste, a storage means for storing the slurry fuel and a burning means for discharging heat, in which the storage tank is heated with the heat from the burning means and the slurry fuel in the storage means is stirred by heat-convention. The system contains a heat-exchange means in which the thermal medium is heated by an exhaust gas containing as internal heat the heat generated in the burning means and the storage means is also heated using the heat of the thermal medium. Another slurry production and storage system comprises a reaction means for producing a slurry fuel from solid waste, a storage means for storing the slurry fuel, a burning means which is cooled with a cooling medium and a bio-gas production means for producing biogas, in which the heat obtained by cooling the burning means is given to the cooling medium and is used for heating the storage means and the bio-gas production means. The burning means can be an internal combustion engine, external combustion engine or fuel cell. EXAMPLE - Solid organic waste (109) such as plant waste, animal waste and food waste was converted to a slurry fuel (110) in a reactor (102) containing subcritical water, in which the solid waste was heated under a high pressure for a certain duration using the system shown in Fig.1. Excess water was removed from the slurry fuel (110) by (103), and the dewatered slurry fuel (111) was stored in a slurry fuel tank (104). An internal combustion engine (105), such as a gas turbine, diesel engine or gas engine, was run using the slurry fuel (111) and produced an exhausted a gas (112) having thermal energy. The slurry fuel could be mixed with paraffin oil, city gas or natural gas, and the mixture was supplied to the internal combustion engine (105). The high-temperature exhaust gas (112) was passed through heat-exchangers (106) and (107), then the heat was transferred to a thermal medium (108) and the thermal medium was heated (102). Instead of the internal combustion engine, an external combustion engine such as a boiler could be used.