Assessing the carbon emission reduction effect of flexibility option for integrating variable renewable energy

Integrating a high-penetration level of variable renewable energy into power systems requires the pro-rata deployment of flexibility technology in the recent trends of low-carbon transition. This study proposes a multi-regional power system optimization model to assess the carbon emission reduction effect of different flexibility options in the Chinese power sector, including total carbon emissions, peaking timetables and values, carbon emission transfer between regional power systems, and carbon emission source changes between technologies. The results reveal that the combinations of dispatchable generation, inter-regional transmission, energy storage, and demand-side response can significantly reduce carbon emissions from power systems, but will lead to higher expenditure. Carbon emissions would peak 1–6 years in advance under the integrated flexibility option consisting of all flexibility technologies, and the corresponding peaking value would decrease by 0.26–0.48 billion tonnes compared to other configuration scenarios. However, this does not apply to all the regions. The coupling relationship between the flexibility option and carbon emission reduction in regional power systems changes with the disparities in power demand, system structure, and renewable energy consumption targets.