Progress in Signals and Telecommunication Engineering Taner Çevik, Fatih Özyurt 4 2 2015 http://www.dline.info/pste/fulltext/v4n2/v4n2_2.pdf Limited energy is the major driving factor for research on wireless sensor networks. Clustering alleviates this energy shortage problem by reducing data traffic conveyed over the network and therefore several clustering methods are proposed in the literature. Researchers put forward their methods by making serious assumptions such as always locating single sink at one side of the topology or making clusters near to the sink with smaller sizes. However, to the best of our knowledge, there is no comprehensive research that investigates the effects of various structural alternatives on energy consumption of wireless sensor networks. In this paper, we thoroughly analyze the impact of various structural approaches such as cluster size, number of tiers in the topology, node density, position and number of sinks. Extensive simulation results are provided. The results show that the best performance about lifetime prolongation is achieved by locating a sufficient number of sinks around the network area.