The energy loss structure and energy supply–demand balance during the smelting process of a 100 t electric arc furnace （EAF） were quantitatively analyzed. Based on actual industrial production data， individual energy losses during the smelting process were quantitatively decomposed and analyzed， the evolution patterns of energy loss throughout the smelting cycle were systematically revealed， and a mathematical model for the electrical energy supply–demand balance of the EAF smelting process was established. The results show that each additional scrap charge increases the process energy loss by approximately 454.3 kWh. Heat dissipation through water-cooled components is the most significant energy loss pathway of the EAF， with the lost energy reaching 8 000 kWh-10 000 kWh， accounting for 13%-18% of the total energy. The sensible heat loss of flue gas and dust is significantly and positively correlated with the hot metal ratio： the higher the hot metal ratio， the greater the flue gas energy loss， which accounts for 5%-10% of the total energy. The high-temperature thermal radiation generated from the bath， electrodes， and arcs is primarily absorbed by the water-cooled furnace walls and roof， while the external thermal radiation loss is relatively low， accounting for approximately 1.1%. The chemical heat of different scrap types is approximately 50.0 kWh/t； due to variations in slag carryover， volatile matter， and impurity content， the overall energy demand of scrap ranges from 351.5 to 424.8 kWh/t. Based on the staged energy loss characteristics and the energy supply-demand balance， the established model yields a proportion of 95.05% for data with calculation deviations within ±10 kWh/t， with an overall model error of less than 3%. The research findings provide a reliable theoretical basis and data support for intelligent optimization of the EAF power supply curve and for energy saving and consumption reduction.