This paper analyzes the performance of RACH-based small data transmission scheme for LTE/LTE-A networks. Power consumption at random access, signaling, and data transmission phases are analyzed. The energy efficiency of the scheme under different number of preambles, offered loads, packet size and packet inter-arrival time is investigated. The results show that RACH-based small data transmission scheme consumes less energy when more preambles are used and less contending devices are involved. More importantly, the energy consumption of this scheme can be further decreased by increasing the bearer timer.