Chemical looping combustion (CLC) is an emerging combustion technology with an inherent separation of the greenhouse gas CO2. The feasibility of CLC has been proven in various small-scale units worldwide, but the large-scale realization of theoretical or small-scale units is still lacking due to many technical challenges. Most of the existing CLC installations use a configuration of two interacting fluidized bed reactors, and even though the fluidized bed technology is mature and well-established, a high level of uncertainty is included in the attempts to up-scale the reactor system involved in CLC. For progressive scale-up of the new technology, a preliminary design of a 100 MWth pre-commercial CLC unit for gaseous fuels is presented. A reactor-level model was used to predict the performance of such a system, and as a result, the operation of the system was characterized and valuable information of the parameters affecting the process was received. For cost-effective energy generation with efficient CO2 capture, the power plant-level integration of CLC must be conducted carefully, and different plant configurations need to be investigated to find the most optimal solution. Hence, the integration of the reactor system and steam turbine cycle for power production was studied resulting in a suggested plant layout including a CLC boiler system, a simple heat recovery setup, and an integrated steam cycle with a three pressure level steam turbine. A plant-level model was used to evaluate the viability of the plant, and without the purification and compression of CO2, the net cycle efficiency of 42.8% was obtained. It was also found that a drop of 2% points in the degree of fuel conversion decreases the net cycle efficiency by about 1% point. (C) 2013 Elsevier Ltd. All rights reserved.