Abstract: Photovoltaics, wind power and the other renewable energy sources are widely connected to the power grids by inverters. Evaluation of the power transfer capacity of an energy delivery system based on the grid-connected inverters is crucial for ensuring the continuous and stable delivery of the clean energy in the normal or the emergency conditions. First, the power transfer characteristics of the grid-connected inverter system before and after the reactive power compensation are analyzed to learn the safe and stable delivery boundary. Then, the dynamic thermal rating of the power equipment is carried out to release the transfer potential to enhance the output capacity of the clean energy. Following that, the maximum transfer capacity of the renewable energy is determined by considering all types of constraints to ensure the safe and stable operation of the grid-connected systems and the delivery channels. Finally, the maximum transfer capacity of the renewable energy farms in the test system is evaluated. The results show that the clean energy transfer capacity is able to be significantly enhanced with the reactive power compensation and the utilization of the dynamic thermal rating of the power equipment. The dominant factors that limit the power transfer capacity are different for different grid connection strengths and operating conditions, and the power transfer capacity limited with the dominant factors will ensure the safe and stable operation of the power system.