To address the issue of strong fluctuations in renewable energy generation and enhance renewable energy utilization

this paper designs a hybrid grid-connected/off-grid wind-solar-hydrogen-alcohol integrated system. Aiming for optimal system lifecycle economics

this paper constructs a mathematical model incorporating detailed constraints for key equipment— including wind and solar generators

electrolysers

and hydrogen storage tanks— to enable flexible grid-connected/off-grid mode switching. Using annual power data from a wind-solar plant in Inner Mongolia in 2021

the model is solved via mixed-integer linear programming in Python to analyze system capacity configuration

operational scheduling

and bidirectional grid support mechanisms. Results indicate that both grid-connected and off-grid systems effectively integrate renewable energy while ensuring continuous

stable synthetic methanol production. Furthermore

the grid-connected system demonstrates greater flexibility and reduced storage requirements due to its grid interaction capability

yielding significantly higher economic benefits than the off-grid system.