In the context of greenhouse gas emissions mitigation, CO2 capture and storage is regarded as a promising alternative for fossil fuel fed power plants. In order to design and evaluate the competitiveness of such complex integrated energy conversion systems, a systematic comparison including thermodynamic, economic and environmental considerations is necessary. From a process engineering perspective, it is important to evaluate the impact of CO2 capture not only on the efficiency but also on the costs and on the environmental impacts, and to assess the trade-offs. This paper presents the development of a systematic thermo-environomic optimisation strategy for the consistent modelling, comparison and optimisation of fuel decarbonisation options. In particular, it is highlighted how the economic scenario influences the competitiveness and hence the optimal process design.