Integrated Decarbonization Pathways for Regional Power Systems: A LEAP–NEMO Analysis in Guangxi, China

Achieving deep decarbonization while maintaining power system operational feasibility represents a critical challenge in regions with a high penetration of renewable energy. In this study, we developed an integrated LEAP–NEMO modeling framework to evaluate long-term decarbonization pathways and power system flexibility in Guangxi Province, China, from 2022 to 2060. Four scenarios were designed, the Business-as-Usual Scenario (BAS), the Policy Strengthening Scenario (PSS), the Technology-Centered Scenario (TCS), and the Integrated Optimization Scenario (IOS), to assess the impacts of policy, technology, and system-level coordination. Our results show that under the IOS, renewable electricity reaches approximately 78% by 2050 and further increases to 88% by 2060, while coal consumption declines by over 60% compared with the baseline. Energy storage deployment under the IOS reaches 25 GW by 2060 (rising to approximately 28 GW under a higher-resolution 48-representative-day validation), approximately five times the level in the BAS (5 GW), significantly enhancing system flexibility and reducing renewable curtailment from 10.2% to 1.8%. Carbon emissions peak in 2027 at 228 Mt CO2, approximately 20% lower than the baseline, and decline to 52 Mt CO2 by 2060, achieving a cumulative reduction of 3.85 Gt CO2. Economically, the IOS pathway reduces total system costs to USD 815 billion, saving approximately USD 95 billion compared with the BAS, with the levelized cost of electricity declining to USD 63/MWh by 2060. These results demonstrate that integrated optimization of generation and storage resources is essential in achieving deep decarbonization while maintaining system deterministic capacity adequacy and economic efficiency.