A new way to evaluate the energetic performance of lime shaft kilns is proposed. Two new exergy-based indicators are introduced for the evaluation, one to assess the exergy efficiency of limekilns and the other indicator to assess the effectiveness of the exergy consumption of the dissociation reaction. The combination of both indicators provides a clear picture of the energetic performance of the process, highlighting the main potentialities for fuel saving (fuel consumption represents about 50% of total production costs). The validity of the proposed assessment is examined using some operating data measured in a commercial lime factory. Results show that introduction of exergy-based indicators in the assessment improves the evaluation of the energy consumption of the calcination process. In this way the impact of the process losses in the fuel consumption is better addressed. (C) 2011 Elsevier Ltd. All rights reserved.