99.6% efficiency DC-DC coupling for green hydrogen production using PEM electrolyzer, photovoltaic generation and battery storage operating in an off-grid area

• Published in: Renewable energy 2024-12, Vol.237, p.121781, Article 121781
• Main Authors: Sánchez-Squella, Antonio, Flores, Ricardo, Burgos, Rolando, Morales, Felipe, Nader, Andrés, Valdivia-Lefort, Patricio
• Format: Article
• Language: English
• Subjects: DC-DC converter; Electrolyzer; Green hydrogen generation; Off-grid systems; PEM; Photovoltaic; Reliable operation; Solar photovoltaic; Underactuated control
• ISSN: 0960-1481
• DOI: 10.1016/j.renene.2024.121781

This paper presents a novel connection and control strategy for a hydrogen generation system using a proton exchange membrane electrolyzer powered by solar energy in an off-grid area without network backup. Given that, the proposed architecture is based on the indirect control of the Photovoltaic plant (achieved by removing a power-converter), the presented solution is more efficient and more reliable than the traditional scheme. Furthermore, with this innovation one can reach the same hydrogen production with smaller electrolyzers. The methodology includes detailed models of the photovoltaic panel and the electrolyzer, along with a control strategy that considers the degradation mechanisms of the electrolyzer to ensure reliable and prolonged operation. The results show that the proposed strategy keeps the operating power of the electrolyzer constant, even under variations in irradiance, thanks to energy storage in batteries. It is demonstrated that the proposed system offers efficiency above 99.6% during the analyzed period, with a 100% utilization rate of the electrolyzer, avoiding periods of inactivity and high current peaks. The study also includes simulations and experimental tests that confirm the feasibility and effectiveness of the presented solution, highlighting its advantages in terms of efficiency and investment costs compared to direct connections and other existing methods. •Accomplished MPPT control in PV plants without dedicated power converter.•99.6% efficiency was achieved in hydrogen production with PEM electrolyzer and photovoltaic systems.•The proposed system control eliminates electrolyzer downtime, achieving a 100% utilization rate.•Experimental results demonstrate the system’s superior energy management strategy•Improved reliability through control and power system design for green hydrogen production.