A holistic picture of the carbon emission responsibility in China's aluminium supply chain: Production-side flow analyses, consumption-side responsibility allocation, and driving factor analysis

As a highly electrified industry with increasing demand, decarbonization in the aluminium smelting and processing industry (ASPI) involves critical aspects such as production-side energy structure and consumption-side material conservation, necessitating a collective strategy. However, the disjointed approaches of these sides hinder a holistic view for policy design. This study developed a comprehensive method to clarify carbon emission responsibilities for ASPI's production and consumption, which traces the emission allocation chain from bauxite supply, aluminium smelting, aluminium consumption to final demand by integrating material-energy-carbon flow analysis with the extended input-output method; and further decomposes the emission contributions of economic, material, and energy factors. The method's application on China reveals that from 2008 to 2020, CO2 emissions of China's ASPI increased from 267 Mt to 538 Mt. The sustained final economic demand growth significantly contributed to this rise, while the impact of suppression factors, including unit energy consumption, was limited. In 2020, investment drove 56.1 % of ASPI's emissions, leading the buildings and infrastructure sector to be responsible for 40.2 % of embodied consumption emission responsibility. This study recommends that China's ASPI focus on revitalizing existing idle assets while balancing new investments; and encourage the inclusion of distributed generation to break the path dependency on coal-fired power.