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 H2, 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 H2 to that of coal based processes.