Prospect and Challenges of Hydrate-Based Hydrogen Storage in the Low-Carbon Future

Hydrogen hydrate is a promising materialfor safe and potentiallycost-effective hydrogen storage. In particular, hydrogen hydrate haspotential for applications in large-scale stationary energy storageto dampen the temporal variation of renewable energy, for example,in the form of hydrogen-ready gas-fired power plants for generatingenergy when the renewable power is not available. Preliminary SWOT(strengths, weaknesses, opportunities, threats) analysis indicatesthat such hydrate-based hydrogen storage (HBHS) has intrinsic competitiveedges. However, while the theoretical hydrogen density of the hydratecould reach & SIM;5 wt %, experiments have not achieved such a highhydrogen storage capacity under practical conditions. This low gravimetrichydrogen density, plus the slow kinetics of hydrogen inclusion inthe hydrate, presents an outstanding challenge for commercializingthe HBHS. Future research is urged to resolve both the gaps in knowledgeand technological barriers for realizing this unconventional technology.Particular future directions include the elucidation of the workingmechanism of hydrate promoters, rational designs of new promoters,upscaled experiments and demonstrations, the assessment of long-termstability of hydrogen hydrates, and systematic SWOT analysis. Thispaper offers an insightful view of the HBHS in low-emission economies.