A stochastic method to compute the operation of active distribution networks (DNs) under different configurations with renewable distributed generators (DGs) and energy storage (ES) systems is proposed. Based on this method, evaluations of the effect on minimizing the total hourly operation cost under the integration of all or a part of wind, solar DGs and ESs is completed. The uncertainties of load demand, wind speed and solar irradiance, as well as the carbon emission cost are also considered. The simulation results show the large potential of carbon emission trading in improving the penetration rate of renewable energy (especially for wind energy without large-scale deployments of ESs in active DNs), and the advantages of hybrid renewable DGs compared to wind, solar DGs solely.