Inter-regional carbon flows embodied in electricity transmission: network simulation for energy-carbon nexus

Energy use and CO2 emissions are inextricably linked. Energy utilization leads to an increase in CO2 emissions, which will in turn limit the formulation of energy policies and stability of energy systems. A provincial-scale Energy-Carbon Nexus Model is established to shed insight into the complicated system interactions among provinces. Specifically, different power generation types are considered to quantify the inter-provincial transfers of CO2 embodied in electricity transmission through the Multiregional Input-Output Analysis. Ecological Network Analysis is used to describe the integral mutual relationships between provinces and distinguish the control intensity of each province from different CO2 flows directions. Five new Energy-carbon emission factors are first performed to provide a more accurate assessment of the province's emissions capacity from different perspectives. Based on the theoretical basis of energy-carbon nexus, the emission reduction simulations considering energy substitution policy can be conducted to forecast the changes of provincial responsibility under different interventions. Results show that some provinces (e.g., Beijing) depend heavily on the supply of other provinces because of their low self-sufficiency rate in electricity, while some provinces (e.g., Guangdong) have high self-sufficiency rate and still emit more CO2 to other provinces to promote their own development. The importance of East China to the system cannot be ignored, but it should also undertake more responsibility for reducing emissions. However, the pace of development in Shandong will slow down because it mainly relies on coal power generation to indirectly promote the development of other provinces. What's more, importing electricity to achieve emission reduction may result in a rebound in indirect emissions and have a negative impact on the region's use of its own energy resources. This paper offers a new way to reveal details of energy-carbon interrelations across provinces and the achievements could provide references for formulating CO2 reduction policies of China electricity trading.