In this paper, we will give the results of the analysis of thermopower units with circulating fluidized bed boilers (CFBB) where we applied a global methodology to estimate the energy-ecologic efficiency of these units described in two papers previously published in this journal. Using this methodology, once more, we conclude that CFBBs with limestone share in the furnace are more advantageous from the technical and economical points of view than conventional boilers using coal with sulphur content as fuel. Also. if we accept the principle of the above mentioned methodology regarding the reciprocal compensation of SO2 and NOx from the flue gases, we can obtain more economical advantages by reducing the limestone quantity needed to desulphurize. (C) 2001 Elsevier Science Ltd. All rights reserved.