The wind is a highly variable energy source and behaves far differently than conventional energy sources. This paper presents a methodology for capacity adequacy evaluation of power systems including wind energy. The results and discussions on two representative systems containing both conventional generation units and wind energy conversion systems (WECS) are presented. A Monte Carlo simulation approach is used to conduct the analysis. The hourly wind speeds are simulated using an autoregressive moving average time-series model. A wide range of studies were conducted on two different sized reliability test systems. The studies show that the contribution of a WECS to the reliability performance of a generation system can be quantified and is highly dependent on the wind site conditions. A WECS can make a significant reliability contribution given a reasonably high wind speed. Wind energy independence also has a significant positive impact on the reliability contribution of multiple WECS.