Abstract: This article analyzes the energy-efficiency performances of fixed relaying schemes, selection relaying schemes and incremental relaying schemes in the three-node relay network. The closed-form asymptotic energy per good-bit (EPG) expressions for the state-of-the-art relaying protocols at high signal-to-noise ratio (SNR) regime are derived. In the formulation of the energy consumption model, the transmission, circuit and retransmission energies are all taken into account. To facilitate the comparison of energy-efficiency performances between different relaying protocols, the link reliabilities and retransmission probabilities are determined by the asymptotic outage probabilities at high SNR regime under the Rayleigh fading assumption. Computer simulations are carried out in both symmetric and asymmetric relay networks. The simulation results show the differences of system energy expenditure between these state-of-the-art relaying protocols. Finally some practical implications can be made from the observation.