This year is the 5th time that we present in the journal Thermal Science selected papers presented at the Dubrovnik Conference on Sustainable Development of Energy, Water and Environment Systems. th Dubrovnik Conference, held from September 25 to 30, 2011, in Dubrovnik, roatia, was faced with the increasing sense that further uncontrolled using of the limited natural esources will soon produce severe economic, social, and political problems. Developing ountries are specially faced with lack of the fuel and energy potentials to support increasing energy emand, necessary for fast industrial development and rapid population growth. At the ame time developing countries need enormous investments in modern, efficient and environmentally cceptable energy technologies. election of papers made by Guest Editors was aimed to point out main problems and asks of the energy strategies and strategies of scientific and technology development, necessary o be solved in the countries of the South East European region if they want to satisfy modern requirements f the European Union i. e., the requirements of the sustainable energy development, nd at the same time reduce dependence on imported energy and fuels. ost of the countries in the region have an additional problem - their energy systems re relying on the only domestic energy potential - low quality coal, and need rapid change of he energy technology used, and sophisticated planning to increase use of renewable energy ources. amdeeply grateful to the Guest editors, Professors Neven Dui}, Daniel R. Schneider, vonimir Guzovi}, and Predrag Raškovi} for their excellent selection of papers. I am sure that elected papers will greatly help scientists, engineers, and decision making experts in the countries f the South East European region to obtain realistic insight in the problems that are necessary o be solved in order to overcome problems in energy supply, and at the same time to save nvironment and domestic energy sources. n order to support this orientation of the Guest Editors, Editorial board in Part II of his issue additionally selected four papers already accepted for publication in the journal Thermal cience (not presented at the Dubrovnik conference) in order to show that intensive activities re carried out in the region to follow modern technology development and for more intensive se of renewable energy sources.