Sectoral energy-carbon nexus and low-carbon policy alternatives: AÂ case study of Ningbo, China

The intensive energy consumption in urban sectors is aggravating global warming, which triggers an in-depth thinking about energy-carbon nexus and low-carbon city actions. Hence, China has launched a pilot low-carbon city program to explore low-carbon pathways since 2010. This study employed a Long-range Energy Alternatives Planning System model (LEAP) to simulate six energy sectors-related GHG emissions in a pilot low-carbon Ningbo city, China. The LEAP-Ningbo model comprises three basic modules, i.e. energy supply, energy transformation and end-use energy demand in six urban sectors (i.e., household, service, agriculture, transport, industry, and transformation sectors), and resulting environmental impacts (CO2 equivalents). The results identified by the business as usual (BAU) scenario indicate that total energy consumption is expected to reach 449.72 Mtce and results in emissions of 651.83 Mt CO2e by 2050. In contrast, more aggressive policies and strategies involved in the integrated scenario (INT), which combines the energy structure optimization (ESO) scenario with the policy-oriented energy saving (PES) scenario, can lower energy demand by 14% and CO2e emissions by 27%. A comparison among global cities and low-carbon plans helps identify the carbon emission level and define the actionable low-carbon policies. The high correlation between sectoral energy use and resulting GHG emissions implies energy-carbon reduction efforts, e.g., low-carbon energy substitution, intensive energy-saving policies, the improvement of energy efficiency, and industrial transformation. Achieving low-carbon city targets requires timeline-restricted actions and backgrounds-based measures in plans. The results of this study shed light on if and how cities can shape energy-carbon reduction trajectories and develop low-carbon pathways in China and beyond.