This paper presents theoretical study of the concept of a small-scale combined cycle system composed of natural gas fired microturbine and Organic Rankine Cycle, integrated with thermal gasification of biomass. A conventional natural gas fired microturbine engine is applied within the system. Gaseous fuel from an updraught biomass gasification reactor is burned in duct burners located in the exhaust gas stream downstream of the turbine. Enthalpy of the combustion gases is used in the ORC cycle. The only product of the system is electric energy. Mathematical modelling of the system gives estimated values of achievable power and energy efficiency of the proposed setup. The plant can be considered as a robust technology for utilization of scattered biomass resources located in places where a natural gas network is available. The main issues addressed in the paper are: configuration of the ORC technology and allocation of generated electricity between natural gas and biomass. Energy and exergy allocation keys are demonstrated. An initial cash flow calculations are presented in order to assess financial performance of the plant. (C) 2017 Elsevier Ltd. All rights reserved.