Wind power integration in an existing power system needs more attention due to its uncertain nature. If a difference creates between the actual and forecasted wind speeds and the power delivery contract is signed between the Generation Companies (GENCOs) and Distribution Companies (DISCOs) as per the forecasted speed, then the GENCOs may be awarded or penalized by the Independent System Operator (ISO) for their surplus or deficit power supply. This paper proposes an approach to assess the uncertainties of wind speed of the wind integrated electrical system within a completely deregulated environment. In this work, twelve spots in India have been chosen randomly for the application of the proposed approach and to verify the outcome of the proposed approach. The real time data for actual wind speed (AWS) and forecasted wind speed (FWS) of all selected spots have been also considered. The imbalance cost due to mismatch between the forecasted and actual wind speeds is evaluating by formulation of surplus charge rate and deficit charge rate. Modified IEEE 14-bus and modified IEEE 30-bus systems are considered for analyzing the effectiveness of the proposed approach. (C) 2017 Elsevier Ltd. All rights reserved.