Advanced Control Strategies for Power-to-X Systems: Enhancing Green Hydrogen Production from Variable Renewable Energy Sources

Abstract

The integration of variable renewable energy sources with Power-to-X systems presents critical operational challenges. Conventional control approaches cannot simultaneously optimize hydrogen production efficiency, minimize electrolyzer degradation, respond to dynamic electricity pricing, and provide grid frequency regulation services. Existing proportional-integral (PI) control methodologies prove inadequate for managing these competing demands in systems coupling intermittent solar and wind inputs with electrolysis designed for steady-state operation. Therefore, this research develops and validates advanced control strategies incorporating hierarchical Model Predictive Control (MPC) with adaptive elements for optimizing green hydrogen production from variable renewables. We implement a three-layer architecture separating strategic planning, tactical optimization, and operational execution, validated through comprehensive simulations using realistic renewable profiles from operating installations and experimental testing on a 50kW proton exchange membrane electrolyzer. The results show that the proposed adaptive MPC framework achieves 18.3% higher hydrogen production efficiency during high-variability periods (95% CI: 14.7-21.9%) compared to baseline PI control, with 34.7% reduction in thermal cycling stress, translating to an estimated 22% equipment lifetime extension. Economic analysis demonstrates 12.5% reduction in levelized hydrogen cost through improved capacity utilization and optimized response to electricity price signals. Experimental validation confirms simulation predictions within 8-12% error margins across multiple operating scenarios, with detailed mismatch analysis identifying transient conditions as primary deviation sources. These findings establish practical viability for industrial-scale Power-to-X deployment, demonstrating that advanced control enables dual-purpose operation—simultaneous hydrogen production and grid service provision—essential for renewable energy integration. The modular control architecture facilitates adaptation across diverse electrolyzer technologies and renewable configurations.