Multi-Timescale Coordinated Low-Carbon Dispatch of CCPP–BECCS Considering Carbon Capture Energy Flexibility

Coordinating carbon capture power plants (CCPPs) with bioenergy with carbon capture and storage (BECCS) requires balancing electrical flexibility, operating costs, and biogenic carbon removal. This paper proposes a multi-timescale coordinated dispatch model for a flexible CCPP and a coal–biomass co-firing BECCS unit. The model integrates absorption–regeneration decoupling, rich solvent storage, flexible biomass allocation, and source-differentiated carbon accounting. Explicit reserve activation constraints jointly represent generation ramping, capture load adjustment, solvent availability, and DC network limits. A two-stage scenario formulation determines common day-ahead commitment and scenario-dependent dispatch, followed by intraday and real-time adjustments. Case studies on a modified IEEE 39-bus system include technology comparisons, equal removal benchmarks, independent synthetic forecast error tests, and economic sensitivity analyses. The results show that biomass utilization depends on both economic conditions and carbon removal requirements. Under an identical biogenic removal requirement, flexible co-firing reduces operating costs and system net emissions relative to fixed co-firing while capture electricity consumption increases. Scenario-based commitment reduces reserve shortfalls in the hourly uncertainty tests, although the improvement does not persist in the finer-resolution evaluation. The proposed model quantifies the complementary roles of capture load flexibility and biomass allocation, providing a basis for coordinating electrical regulation and carbon removal services under network and operating constraints.