Enhancing solar-powered hydrogen production efficiency by spectral beam splitting and integrated chemical energy storage

Solar energy-powered electrolytic water splitting represents a promising avenue for hydrogen production. However, current technologies for solar-driven hydrogen generation still face the challenges such as low efficiency and significant fluctuations in solar energy availability. This paper proposes a full-spectrum solar hydrogen production system integrated with spectral beam splitting technology and chemical energy storage to address these issues. The high-grade solar energy is allocated for generating electricity through photovoltaic cells, while the low-grade solar energy is utilized in the dry reforming of methane (DRM) process to produce syngas, which in turn is used for flexible electricity generation. Dispatchable electricity converting from syngas, along with intermittent electricity form photovoltaic cells, powers a solid oxide electrolysis cell (SOEC) to produce hydrogen. The results demonstrate that the energy efficiency is 32.08%. In addition, more than half (56.6%) of the electrolysis capacity can be utilized during night hours due to thermochemical energy storage (syngas). In addition, a year-long operation simulation showed that the system can diminish CO₂ emission by 25.7% to produce the same amount of hydrogen. The full-spectrum solar hydrogen production system provides a viable option for the transition from fossil energy to renewable energy.