Fluctuation Analysis of a Complementary Wind-Solar Energy System and Integration for Large Scale Hydrogen Production

Producing hydrogen by water electrolysis with solar and wind energy will be one of the main methods of hydrogen production. The inherent intermittency and volatility are, however, the biggest obstacles to the utilization of these low-carbon resources. This limitation leads to an urgent need for fundamental analysis and system integration of renewable energy sources. In this paper, the random fluctuations of wind and solar energy were characterized by the spectral analysis method to explore underlying laws within. The base models of wind power and photoelectric (PV) power were defined to reveal the intermittent characteristics and phase difference. On this basis, we proposed the theoretical foundation of wind-PV complementation. For a case study, an industrial-scale wind-solar to hydrogen system (WPTH) is proposed to provide high-purity hydrogen. We chose the hydrogen production scale of the system to be 3.4 t/h with a fluctuation of hydrogen supply less than 7.5%, according to the reasonable unit capacity configuration. Through life cycle model analysis, the carbon footprint of this process is 1.19 kg CO2/kg H-2, far lower than that of coal based hydrogen production. On the other hand, this process is found to have the close cost of 3.59 $/kg H-2 to that of coal based processes.