Abstract: Under the "Dual Carbon" goals, precise management of carbon allowances is crucial for thermal power enterprises to fulfill compliance obligations and enhance asset value. Taking Laicheng Power Plant as a case study, this paper addresses the issue of carbon allowance loss caused by incomplete heat supply measurement. By installing high-precision calorimeters and incorporating heat supply from the urea hydrolysis area into accounting, the plant has achieved precise unit-level measurement and full-process traceability. This technical modification can increase the plant’s annual heating-related carbon allowance by 9,022 tons, effectively alleviating compliance pressure. It also provides a practical pathway for similar enterprises to implement lean management of carbon allowances.