Optimization framework for the synthesis of power systems has been presented in Part 1 of this article, which systematically identifies the most cost-efficient number, type, and model of mechanical drivers, together with optimal arrangement for compressor stage, helper motors or generators, and power plants. The developed methodology is applied to an LNG case study in which optimal and near-optimal systems at various economic scenarios are identified. Also, a systematic methodology for the integrated design of refrigeration and power systems has been addressed to improve the overall design of low temperature processes. Additional key degrees of freedom such as stage pressure ratios and plant capacity are optimized, alongside other design variables, which provide greater flexibility in the matching of power supply and demands. This strategy is applied to an LNG case study and shows the convenience of this approach as the interactions between the refrigeration and power systems are systematically exploited. (C) 2010 American Institute of Chemical Engineers AIChE J, 56: 2377-2389, 2010