Abstract: concept of the new electric power system and the new generation of coal power indicate that the advanced coal power units will be designed and operated based on 15%-20% load, so the minimum output and energy consumption under low loads are the core issues. In view of the above two problems, the bottleneck and influencing factors of units under deep peak shaving, the minimum output of existing and newly built units, the coal consumption under deep peak shaving of existing units, and the optimal design of the next-generation coal-fired power generation were analyzed and studied. Results show that the overtemperature of the pipe wall and metal fatigue damage, poor combustion stability, and high pressure of denitration equipment occupied the highest three risk indexes of low load deep peak shaving. In the 20%-35% load range, the coal consumption increase ratio of 300 MW and 660-1 000 MW units is 2.6 and 9.2 g/(kW·h) each percentage load, respectively. The coal consumption of a 660 MW ultra-supercritical unit at 15%-20% load increases by 31.2 g/(kW·h) each percentage load due to such as wet operation, disproportionate decreases for fuel and working medium flow rate, and the increased plant electricity consumption rate. For coal power units with capacity ≥600 MW, in the heat absorption process of molten salt heat storage system, the original minimum output of 20% and 30% load units can be reduced by 20% and 53%, respectively. It is suggested that the unit maintain dry operation under 15%-20% load, and reduce coal consumption by reducing water supply and adopting circulating pump system if wet operation is required. The 300 MW unit should be used as far as possible for deep peak regulation under ultra-low load.