For efficient design and operation of technical processes, accurate simulations are essential. Therefore, a precise representation of thermophysical properties using an adequate thermodynamic model is necessary. The GERG-2008 (Kunz, Klimeck, Wagner, & Jaeschke, 2007; Kunz & Wagner, submitted for publication) is the new reference equation of state for natural gases consisting of up to 21 specific compounds. As the equation of state describes the gas and liquid phase as well as the super-critical region and the vapour-liquid equilibrium with the highest accuracy available, it has high potential for accurate process-modeling. In order to implement the software available for the new equation into various common simulation tools, the GERG-2008 Property Package has been developed, which complies with the CAPE-OPEN standards specification. The influence of thermodynamic models on the simulation of the only liquefaction plant for natural gas existing in Europe is investigated. Results show significant improvements in accuracy for simulations using the new thermodynamic model. (C) 2011 Elsevier Ltd. All rights reserved.