Biomass post fired hydrogen production combined cycle (BPFHPCC) is proposed and analyzed via common exergy and exergoeconomic analyses. In order to have an objective insight and especially realistic approach to the cycle's thermodynamic and exergoeconomic performance, modified approach is applied. Within common exergy analysis, the components with high exergy destruction are respectively, the combustion chamber, heat recovery steam generator and gasifier while with modified exergy analysis they are the gas turbine, steam turbine and post combustion chamber. As far as components exergy destruction cost rate are concerned, with common analysis the highest exergy destruction cost rates are for the combustion chamber, heat recovery steam generator and steam turbine while with modified analysis they are the combustion chamber, gas turbine, and steam turbine. In this system hydrogen is used for other units. However, if we want to use it within the system, the case in which hydrogen is injected into the combustion chamber is extended. The effects on the thermodynamic efficiency and system product cost were negative while it decreased the system CO2 emissions, exergy destruction and loss rates as well as the exergy destruction and loss cost rates. (C) 2018 Elsevier Ltd. All rights reserved.