Estimate of ecological efficiency for thermal power plants in Brazil Electo Eduardo Silva Lora * , Karina Ribeiro Salomon Thermal Systems Study Group, Federal University of Itajuba ´, NEST Av. BPS 1303, CP 50, Itajuba ´, MG, CEP 37.500-903, Brazil Received 1 October 2003; received in revised form 15 March 2004; accepted 24 June 2004 Available online 26 August 2004 Abstract Global warming and the consequent climatic changes that will come as a result of the increase of CO 2 concentration in the atmosphere have increased the worldÕs concern regarding reduction of these emissions, mainly in developed countries that pollute the most. Electricity generation in thermal power plants, as well as other industrial activities, such as chemical and petrochemical ones, entail the emission of pollutants that are harmful to humans, animals and plants. The emissions of carbon oxides (CO and CO 2 ) and nitrous oxide (N 2 O) are directly related to the greenhouse effect. The negative effects of sulfur oxides (SO 2 and SO 3 named SO x ) and nitrogen oxides (NO x ) are their contribution to the formation of acid rain and their impacts on human health and on the biota in general. This study intends to evaluate the environmental impacts of the atmospheric pollution resulting from the burning of fossil fuels. This study considers the emissions of CO 2 , SO x , NO x and PM in an integral way, and they are compared to the international air quality standards that are in force using a parameter called ecological efficiency (e). Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Thermal generation; Atmospheric emission; Ecological efficiency 0196-8904/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.enconman.2004.06.028 * Corresponding author. Tel.: +55 35 3629 1321; fax: +55 35 3629 1355. E-mail address: electo@unifei.edu.br (E.E.S. Lora). www.elsevier.com/locate/enconman Energy Conversion and Management 46 (2005) 1293–1303