A high penetration of renewable electricity generation requires an improved understanding and modelling capability of renewable energy resource dynamics. This paper develops such a capability for wind. Using historical hourly wind speed data, an enhanced methodology for modelling wind, which includes seasonal, daily, hourly, and location related factors, has been developed. The methodology uses a set of day types, evaluating their frequency in real wind data, to generate hourly synthetic wind speed data, which is critical to designing a high wind penetration energy system. The methodology is applied to three different locations and the results compared to a commonly used method for synthetic wind speed data. It is concluded that the new method constitutes an important advance in simulating the occurrence of different types of wind days, which is particularly relevant in energy systems planning, especially in evaluating the frequency and scale of surpluses and shortages of wind power, and the necessity for and dimensioning of a storage system. V C 2012 American Institute of Physics.