All players in the US electricity industry must understand how specific generation decisions, wheeling arrangements, and legislative initiatives affect system operations. This article features PowerWorld, a comprehensive power system simulation package developed to help meet this need. The package is designed for the many new players in the power industry who will never operate an actual system but who must have a basic understanding of its operations. The package, which runs in the Microsoft Windows environment, is user friendly, interactive, and menu driven. It effectively uses visualization techniques to present the basics of power system operations and control simply, yet also with a level of detail to accurately model large-scale systems realistically and with the appropriate level of fidelity. The package has been demonstrated to policy makers, legislative analysts, small and large utilities, and regulatory decision makers both nationally and internationally. It has been found to be a very effective tool for communicating the many technical and economic impacts of third-party access.