The efficiency of sensor networks strongly depends on the routing protocol used. Most of routing protocols might differ depending on the application, mode of functioning and network architecture. Overall, the routing techniques are classified into three categories based on the underlying network structure: flat, hierarchical, and location-based routing. In this paper, we analyze three different types of hierarchical routing protocols: LEACH, TEEN, and PEGASIS. Furthermore, the paper investigates the power consumption for all protocols. Simulation results show that PEGASIS reduces overall energy consumption and improves network lifetime over its comparatives.