Energy of nodes plays an important role in all kinds of networks whether it is wired network or wireless network, since most of the nodes are battery powered and it is not possible to recharge the battery whenever necessary. In most of the networks, the data cannot be sent completely when the connection is terminated from source to destination. Hence, the concept of delay-tolerant network (DTN) is introduced. In DTN, due to the mobility of nodes most of the nodes have sufficient amount of energy which is required for transferring of data. Energy is crucial issue in the concept of DTN, especially in disastrous like scenario, where recharging of battery becomes difficult. The proper use of energy for data transmission increases nodes lifetime and network lifetime situation. In this paper, some of the energy-saving techniques are explained to reduce the energy consumption of the node and also increase the packet delivery ratio. © Springer Nature Singapore Pte Ltd. 2019.