Under the rigorous guidance of China’s national strategic goals of “dual carbon” (carbon peaking and carbon neutrality), the transformation of energy structures in heavy industries has become a critical priority. In particular, establishing an innovative energy supply system for the alumina digestion process that is predominantly powered by green electricity is essential. This transition is pivotal for promoting a comprehensive zero-carbon transformation, significantly enhancing the utilization efficiency of renewable energy resources, and effectively reducing the operational costs of the system.

To address these challenges, this study constructs a novel green electricity-molten salt synergistic hybrid system, supported by advanced wind and solar forecasting techniques, to supply reliable power for the alumina digestion process. Regarding the methodological framework, a sophisticated hybrid prediction model combining the autoregressive integrated moving average model (ARIMA) and a long short-term memory (LSTM) network is developed to achieve precise meteorological data forecasting. Furthermore, the non-dominated sorting genetic algorithm III (NSGA-III), integrated with a fuzzy satisfaction function, is utilized to conduct a rigorous multi-objective optimization configuration study. This comprehensive simulation covers a continuous period of 1 week (168 h) and evaluates performance across 12 typical operating scenarios to ensure robustness.

The comprehensive empirical results indicate that the prediction accuracy of the proposed model is exceptionally high, with the average coefficient of determination (R²) value for meteorological data exceeding 97.5%, thereby providing reliable data input for system control. The optimized full-equipment configuration demonstrates significant advantages in maintaining a cross-seasonal stable energy supply, achieving an optimal balance among economic viability, environmental impact, and overall energy efficiency. Specifically, the minimum weekly operating cost is recorded at 6.322 9 million yuan, the lowest carbon emission is reduced to 44.97 t, and the maximum effective green electricity rate reaches an impressive 99.67%. Additionally, the configuration of molten salt thermal energy storage equipment effectively smooths the inherent fluctuations of green electricity and drastically reduces reliance on external grid power purchases, resulting in an average green electricity supply proportion of 98.23%. The strong synergistic effect between wind turbine equipment and photovoltaic equipment successfully compensates for the temporal and intensity limitations of single energy sources, significantly improving both the effective green electricity rate and the stability of the system’s energy supply.

The proposed green electricity-molten salt synergistic hybrid system successfully realizes a stable green power supply, providing robust theoretical support for the optimization of low-carbon, low-cost alumina digestion processes powered directly by green electricity.