Many energy efficient routing protocols have been proposed in sensor networks for different scenarios and various applications in literature. One of the efficient way is to group sensors in the neighboring into clusters and send aggregate data by a designated cluster head. However, such design discipline still can not balance the energy consumption of the entire network. As such, in worst cases, some nodes may be soon exhausted. Consequently, it is difficult to provide effective operation and seamless coverage in such a network. In this paper, we propose a novel clustering associating algorithm, known as Energy Residue Aware (ERA) clustering algorithm, to prolong the lifetime of a sensor network by balancing the energy consumption of the entire network. ERA enables each sensor to associate its cluster head to find a path with maximum energy residue sum instead of a path with the minimum energy consumption. Simulations are conducted to evaluate the performance in terms of the network lifetime and energy distribution among nodes. Numerical results show that proposed ERA can maintain a balanced energy consumption distribution among nodes in a sensor network and thus prolong the network lifetime.