A methodology for CCUS carbon reduction potential and carbon neutrality contribution: multi-scale optimization and empirical exploration

CO₂ capture, utilization, and geological storage （CCUS） serve as a foundational technology for large-scale emission reduction in the fossil energy and industry sectors. To quantify the carbon abatement potential and contribution to carbon neutrality for high-emission enterprises in Hainan driven by CCUS, we constructed a high-precision research framework that integrates enterprise-level carbon emission accounting, block-level storage site screening, techno-economic characterization of CCUS projects, source-sink matching via pipeline cost surface modeling, and carbon abatement prediction. This framework enables kilometer-scale CCUS integrated analysis, achieving the first multi-dimensional assessment of Hainan’s CCUS technologies. It covers storage capacity, site suitability, techno-economics, cluster deployment, and carbon neutrality pathways. Findings show that the Fushan Sag in Hainan possesses geological conditions for CO₂ geological utilization and storage in oil-gas reservoirs and saline aquifers. Key emitters can achieve 90% abatement of total captured CO₂ at a levelized cost of <400 CNY/ton via CO₂ saline aquifer storage. CCUS technologies are projected to yield a cumulative net abatement of 540 million tons for Hainan’s enterprises by 2060, with CO₂-EOR and CO₂-EWR applications peaking in 2040 and 2045, respectively. This study provides critical support for Hainan’s CCUS planning toward carbon neutrality and offers a reference for South-South and island nations to integrate CCUS into their decarbonization and industrial development strategies.