Optimal design of a renewable hydrogen production system by coordinating multiple PV arrays and multiple electrolyzers

Abstract

In the design of a renewable hydrogen production system (RHPS), it is of great significance to coordinate the power generation and electrolyzers for efficient and stable hydrogen production. To investigate the coordination and complementary characteristics of multiple PV arrays and multiple electrolyzers in the optimal design of RHPS, a coordinated design approach based on mathematical optimization for the optimal RHPS with multiple PV arrays and multiple electrolyzers was proposed, which features comprehensive considerations of different characteristics of power generation and economy of different types of PV arrays, and the dynamic operating characteristics and economy of various types and capacity of electrolyzers to adapt to fluctuating hydrogen demand. The optimal configuration of the RHPS with minimal total cost can be obtained by combining multiple PV arrays with multiple electrolyzers. Furthermore, the impacts of power generation on the economy of the system are systematically explored, and electrolyzer types are optimally deployed. The influence of different PV array types on the economics of the system is analyzed. An example of the RHPS was employed to demonstrate the feasibility and effectiveness of the proposed method. Results show that for the RHPS, the selection of the type of electrolyzers is mainly affected by the characteristics of power generation. In the system with only PV arrays for power supply, the total cost of the system with proton exchange membrane electrolyzers (PEMEL) is 11.2% lower than that of the system with alkaline electrolyzers (AEL). In the system with simple wind turbines for power generation, the total cost of the system with AEL is lower than that of the system with PEMEL. The selections of type and capacity of the electrolyzers in the system are affected by the minimal power limit of the AEL. The total cost of the system can be effectively reduced by coordinating the power generation and electrolyzers and combining AEL and PEMEL in the system. The selection of PV types is related to the unit cost and the seasonal changes in the capacity factor of different PV arrays, which is also influenced by the hydrogen demand and the curtailment rate. When the variations of power generation align with hydrogen demands, the total cost can be reduced by lowering seasonal energy storage capacity.