In contrast to an Oxyfuel process with pulverised coal (PC) firing, possible advantages of a circulating fluidised bed combustion (CFBC) are the in-furnace sulphur dioxide removal no additional sulphur dioxide removal downstream the steam generator might be necessary and the feasibility for concepts with a reduced flue gas recirculation. In [1] design conditions for the overall process of an Oxyfuel CFBC with highest flue gas recirculation up to 75% are compared to concepts with less recycled flue gas. Compared to [1], this work is not focussed on design aspects of the steam generator but rather on the changing structure of auxiliary power demand of an integrated overall process caused by a reduced flue gas recirculation. At full load operation and under realistic boundary conditions achievable efficiencies of an Oxyfuel CFBC will be examined and compared to the PC-fired Oxyfuel process.