NOVELTY - The reactor (1) has a heat exchanger (3) integrated to supply assembly (12) for gaseous oxidizing agent such as air or steam, to exchange heat energy produced from electricity over an electrical resistance by a heating element (17) of supply assembly, with the air. The control and supply of electricity are varied and adjusted, to control and arbitrarily adjust the heat production, and temperature of the air.    USE - Thermo-chemical gasification reactor for use in power plant used for gasifying solid fuels such as biomass, coal and peat, for generating fuel gas for combustion engine (claimed) e.g. diesel engine used as pilot jet ignition type engine.    ADVANTAGE - The reliability and thermodynamic efficiency can be improved. The overall efficiency of the power plant can be improved.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) method to determine oxygen concentration of fuel gas exiting the gasifier;    (2) starter system for internal combustion engine attached to thermo-chemical gasification reactor;    (3) method for electrical heating of oxygen sensor integrated to exhaust gas mass flow of combustion engine;    (4) apparatus and mechanism for the mixture of fuel gas produced by thermo-chemical gasification reactor with air to fuel combustion engine;    (5) method for controlling the mechanism for the mixture of fuel gas with air;    (6) method for determining physical properties fuel gas mass flow;    (7) method for determining gas mass flow sucked into combustion engine;    (8) method for determining amount of heat and heat flow from the time integral of electrical heating power of electrical heating elements;    (9) method for determining temperature distribution within thermo-chemical gasification reactor;    (10) method for determining ignition curve and model burn function within the solid fuel within thermo-chemical reaction zone of gasifier;    (11) method for determining the beginning of accelerated oxidation reaction and progress of exothermal reaction;    (12) combustion engine;    (13) drag torque model of combustion engine;    (14) method for determining momentary motoring torque;    (15) method for comparing momentary motoring torque;    (16) method for determining combustion engine internal torque component;    (17) method for cranking combustion engine by starter device; and    (18) method for regular and durable power plant operation.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view illustrating the arrangement of the reactor and other components of power plant.    Reactor (1)    Heat exchanger (3)    Connecting device (4)    Supply assembly for air (12)    Heating element (17)