Wind energy applications are rapidly increasing in power generating systems due to widespread public support for renewable energy. Wind energy, however, has not been considered as an important factor in capacity planning since wind penetration has traditionally been insignificant compared to conventional generation. It will be increasingly important to consider wind energy in generation planning as wind penetration continues to increase. It is difficult to assign a capacity credit to a wind turbine generator since its actual capacity is limited by the random variation of the wind speed and the turbine characteristics. Capacity planning considering wind power requires realistic cost/reliability evaluation techniques that respond to the inherent random variables. This paper presents an evaluation model and applies it to a test system to illustrate the influence of different factors on generation planning.