A novel integration of N-2 production, NH3 synthesis, and power generation systems is designed to efficiently convert H-2 to NH3. The integrated system employs the principles of exergy recovery and process integration to achieve high energy efficiency. The high-purity N-2 output by the N-2 production module is reacted with H-2 in an NH3 synthesis module to produce NH3. In addition, O-2-rich gas, which is a by-product, is utilized as an oxidant in the power-generation module. A single column is adopted in the N-2 production module, and the feed stream is split into two and fed to the middle and bottom of the column. In our tests with the N-2 production module, the two operating parameters of bottom-feed ratio and refed-stream ratio were evaluated in terms of the energy consumed, N-2 purity, and O-2 molar fraction in O-2-rich gas. Compared with previous studies on N-2 production systems, our N-2 production module can reduce energy consumption by about 43% (3.27 MW compared with 5.76 MW to produce 1 tmol-N-2 h(-1)). In the NH3 synthesis and power generation module, the two operating parameters of conversion rate per pass and purged-stream ratio are also evaluated. The calculation results show that a high conversion rate per pass and low purged-stream ratio increase the total energy efficiency, which includes NH3 production efficiency and power generation efficiency. The highest total energy efficiency that can be achieved by the integrated system is 66.92%, which includes a NH3-production efficiency of 66.69% and a net power generation efficiency of 0.23%. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.