Wind integration studies are now routinely undertaken by utilities and system operators to investigate the operational impacts of the variability and uncertainty of wind power on the grid. There are widely adopted techniques and assumptions that are used to model the wind data used in these studies. As wind penetration levels increase, some of the assumptions and methodologies are no longer valid and new methodologies have been devised. Based on involvement in conducting studies, reviewing studies, and/or developing datasets for studies in the Western Interconnect, the Eastern Interconnect, Hawaii, and other regions, the authors report on the evolution of techniques to better model the wind power output for cases with high penetrations of wind energy.