This paper presents steady-state and transient models and optimization of natural gas liquefaction using Aspen HYSYS. Steady-state exergy and heat exchanger efficiency analyses summarize the performance of several potential systems. Transient analyses of the optimal steady-state model produced most of the results discussed here. These results pertain to LNG (liquefied natural gas) generally and to an energy storage process associated with CCC (cryogenic carbon capture (TM)) in which the LNG process plays a prominent role specifically. The energy storage CCC process influences the time constants and magnitudes of the flow rate characteristics. These flowrate variations affect all units, especially compressors and heat exchangers. The proposed process controls temperatures, pressures and other operating parameters. K-value- and U-value-techniques guide flowrate and heat exchanger stream variations. Transient responses to both ramping and step-changes in flow rates indicate process responses, including summary effects represented in transient efficiency graphs. (C) 2016 Elsevier Ltd. All rights reserved.