Design Method of Hybrid Production Systems for Renewable Methanol Using Spectrum Analysis of Renewable Energy Supply

To address the intermittency of renewable energy supply in the production of renewable methanol, an optimal design method of hybrid production systems (HPS) for renewable methanol is proposed, which incorporates the economic merit of scaled production systems (SPS) and the operational flexibility of modular production systems (MPS) to alleviate the adverse impacts of fluctuating renewable energy supply. For the optimal design of the HPS, the strategies of frequency-domain decomposition and power allocation are established by using the cutoff amplitude method in spectrum analysis. A mathematical programming model is developed to simultaneously optimize the system design and operational strategy of the HPS for renewable methanol. The case study demonstrates that the HPS achieves a favorable trade-off between operational stability and economic performance by leveraging the complementary strengths of the SPS and MPS. The results show that when the economic performance is prioritized as the objective, SPS is more effective in accommodating renewable energy supply with high power amplitude and low variability, whereas MPS shows superior adaptability under intensive fluctuation of renewable energy supply. Compared to the standalone SPS and MPS, the HPS not only enhances economic performance while maintaining operational robustness but also significantly improves operational stability and equipment utilization efficiency. This work provides a methodology for the optimal design and operation of renewable methanol production systems under complex application scenarios.