Increased climate changes and environmental pollution cause a decrease of available quality water quantities and increase differences in precipitation amounts by seasons. The question is how to provide sufficient quantities of water to supply the population, agriculture, industry, and electricity generation. Sources of quality water are most often located in areas far from the centers of consumption, so it is necessary to construct large water management systems. In order to mitigate the variations in the available quantities of water during the year, reservoirs of significant, seasonal capacity must be built. The power system stability is additionally endangered by the growing impact of renewable sources with extremely variable electricity generation, which is manifested both on an intraday and seasonal level. Therefore, seasonal accumulations, with multi-purpose and even multiple use of the same amount of water, represent a winning option and a stronghold on which power supply, economic and social security and stability should be built. In the case of Serbia, apart from seasonal ones, there are also a spatial differences in the quantities and quality of water in the river basins. In the areas of Zapadna and Velika Morava, Šumadija, Kolubara and Belgrade, the required quantities of water for the supply exceed their own resources. On the other hand, the Drina basin is rich in water of significantly higher quality, and the possibilities of leveling the waters of river Lim are extremely limited. This paper reaffirms the old idea of building a multi-purpose hydro system „Lim-Zapadna Morava“, which would solve these problems. Beside those in power industry, other positive effects that would be achieved by the realization of this strategic project are also presented in this paper.

This paper presents and elaborates the proposal for reorganization of district heating sector in the Republic of Serbia, in order to increase its efficiency, as well as the proposal for the introduction of a self-sustaining incentives system for investments in infrastructure and thermal systems using renewable energy sources (RES). The goal is to reduce the use of non-renewable energy sources, in order to mitigate environmental pollution, as well as to decrease the share of electricity used for space heating. That way, also the electric power system (EPS) would be relaxed and the degree of primary energy utilization would be increased, by avoiding its conversion into electric and then back into thermal energy. As a comparative example of the applicability of the reorganization proposal, the paper presents experiences from the process of reorganization of the electricity sector in the Republic of Serbia. Within the presented proposal of the incentives system, descriptions of the methods necessary for the establishment of such a system are given, too. Acceptance and implementation of these proposals would contribute to increasing the participation of RES in district heating systems and result in achieving the aforementioned, positive effects of wider social impact and significance.