Power system carbon emission flow analysis considering multiple operating conditions for power sources

The real-time and accurate calculation of electricity indirect carbon emissions is not only the critical component for quantifying the carbon emission levels of the power system but also an effective mean to guide electricity users in carbon reduction and promote power industry low-carbon transformation. Fundamentally, calculating indirect carbon emissions involves allocating direct carbon emission data from the power source side, indicating that accurate indirect emission results rely on the precise measurement of power source emissions. However, existing research on indirect carbon emissions in large-scale power systems rarely accounts for variations in carbon emission characteristics under different operating conditions of power sources, such as rated/non-rated operating conditions and ramping up/down conditions, making it difficult to reflect source-side and load-side carbon emission information variation during providing ancillary services. Quadratic and exponential functions are proposed to characterize the energy consumption profiles of coal-fired and gas-fired power generation, respectively, to construct a refined carbon emission model for power sources. By leveraging the theory of power system carbon flow, we analyze how variable operating conditions of power sources impact indirect carbon emissions. Case studies demonstrate that changes in power source emissions under variable conditions have a significant effect on the indirect carbon emissions of power grids.