The increase of capital investments and operation and maintenance (O&M) costs represents a current limitation to the diffusion of carbon capture systems for the clean combustion of fossil fuels. However, post-combustion systems, such as calcium looping (CaL), for CO2 capture from flue gas are the most attractive carbon capture systems since they can be installed at new plants and retrofitted into existing power plants. This work investigates the pros and cons of employing a calcium looping system for CO2 capture and also as a desulphurization unit. A preliminary techno-economic analysis was carried out comparing a base case consisting of a coal-based power plant of about 550MWe with a desulphurization unit (Case 1), the same plant but with a CaL system added for CO2 capture (Case 2), or the same plant but with a CaL system for simultaneous capture of CO2 and SO2 and the removal of the desulphurization unit (Case 3). Case 2 resulted in a 67% increase of capital investment with respect to the benchmark case, while the increase was lower (48%) in Case 3. In terms of O&M costs, the most important item was represented by the yearly maintenance cost of the desulphurization unit. In fact, in Case 3, a reduction of O&M costs of about 8% was observed with respect to Case 2.