The possibility of fitting wind farms of large power into the power system, and coordinating their work with other classic production facilities, is conditioned from a technical aspect by three basic elements: the development of the transmission network, the system implications of power system operation, and dynamic stability. Potential problems related to the second element are presented in the paper, through previous experiences in the world related to the possibilities of short-term forecasting of wind power production, secondary and tertiary regulation of the workforce, i.e. balancing energy, and production planning and operational management of EES. The paper also presents the results of analyzes carried out on the model of the Croatian EES, based on real wind speed measurements from several different locations where the construction of wind farms is planned, as well as production achievements of the built wind farm Trtar-Krtolin: • Analysis of power changes (variability) on 10-minute and hourly intervals. • Applying a simple wind speed forecast to wind farm production planning. • Simulation of fitting the production of wind power plants into the daily consumption diagrams of the EES of Croatia.