A novel analytical method is proposed to find the reliability, the average failure rate, and the operation and maintenance costs (OMCs) of wind turbine generator based on the site wind data. The failure rate function is developed using wind turbine failure frequency distribution, published by Renewable Energy Information System on Internet, Germany. The presented method works computationally fast and does not require large wind data input, which is a requirement of many existing, commercially available simulation methods. The annually increasing OMCs, computed by this method, give better financial assessment of the wind power projects. The method presented is implemented on an Indian wind site. OMCs are obtained for 20 years. Results match the actual field data, for the survey period, barring their warranty period. It is hoped that the proposed method helps financial investors and equity holders for a better financial assessment of the wind power projects at planning stage.