Wireless sensor networks have small nodes deployed which have small batteries used for operations which consumes or dissipates more battery. As a solution for this energy efficient routing is best optimal way. An energy efficient routing protocol enhances overall performance of the nodes and there by maintains cost at minimum levels. Wireless sensor networks are very time critical some times in scenario of earthquake, volcanic eruptions as node deployed in various geographical part tend to deliver message and if some of node dies due to battery consumption can lead to heavy loss to human life's , animals and many other biotic and a biotic factors present in that location and also nearby locations. Hierarchical routing protocols are best suitable protocols in terms of saving energy in wireless sensor networks such as leach, pegasis, teen, heed.