[Objective] With increasing renewable penetration, thermal power units are shifting from baseload generation to flexible regulation. For integrated energy parks containing coal -fired units, deep peak -regulation capability is essential for renewable accommodation and low-carbon operation. Oxy-fuel combustion power plants (OCPPs) offer advantages in low-load stable combustion and CO₂ capture, but their available downward regulation is constrained by the power consumption, ramping limits, and start –stop characteristics of the air separat ion unit (ASU), together with the boiler’s real-time oxygen demand. Assuming instantaneous oxygen supply may therefore overestimate feasible regulation capacity. This paper proposes a flexible peak -regulation dispatch method for an 2 oxy-fuel-combustion integrated energy system considering dynamic oxygen-supply constraints and liquid oxygen energy storage (LOES) buffering. 

[Methods] An electricity–oxygen–hydrogen–carbon coordinated dispatch model is established, explicitly representing OCPP operation, ASU oxy gen production, power -to-hydrogen (P2H) hydrogen production and by-product oxygen generation, LOES oxygen charging and discharging, hydrogen storage and utilization, and CO₂ capture. During deep peak-regulation periods with surplus renewable generation, additional electricity consumption is allocated to ASU, P2H, and LOES charging, converting surplus electricity into storable oxygen and hydrogen material flows. These materials are released in subsequent periods, thereby temporally decoupling oxygen and hydrogen production from their consumption. LOES is placed between ASU production and OCPP demand as an oxygen buffer, reducing the dependence of low-load OCPP operation on real-time ASU output. A grid–park bilevel optimization framework with iterative response feedback is further developed: the upper-level grid adjusts the dynamic peak-regulation compensation price according to regulation demand, while the lower-level park coordinates unit output, ASU, P2H, LOES, demand response, and CO₂ capture to minimize net operating cost and release feasible downward regulation capacity. 

[Results] Case studies under the specified parameters and operating conditions show that the proposed method improves deep peak-regulation performance while preserving oxygen-supply feasib ility. Compared with the traditional operating mode, the cumulative deep peak -regulation response reaches 596.8 MWh, an increase of 47.6%. Daily operating cost decreases by 15.1%, while direct carbon emissions, calculated from coal and natural -gas combustion net of captured and stored CO ₂, decrease by 77.7%. The results confirm that coordinated ASU –P2H–LOES operation transfers flexible electricity consumption to renewable-surplus periods and uses stored oxygen and hydrogen across time, supporting continuous oxygen supply and CO₂ capture. 

[Conclusion] Oxygen and hydrogen material-flow buffering mitigates the restriction imposed by dynamic ASU oxygen supply on OCPP downward regulation. The proposed method strengthens low -load stable combustion, continuous carb on capture, and low -carbon flexible operation in thermal -power integrated energy parks.