Projecting the levelized cost of large scale hydrogen storage for stationary applications

Hydrogen as an energy vector is considered to be an attractive solution for sustainable energy systems - provided, of course, that the energy is from renewable resources. As for all energy systems, this would require energy storage to alleviate the supply and demand disparity within the energy value chain. Despite a great deal of effort to reduce the cost of hydrogen generation, there has been relatively little attention paid to the cost of hydrogen storage. This article determines the levelized cost of hydrogen storage (LCHS) for seven technologies based on the projected capital expenditure (CapEx), operational expenditure (OpEx), and decommissioning cost. Our analysis quantitatively demonstrates the impact of different storage cycle lengths on storage system economics, with LCHS dramatically increasing for long-term storage despite a radical decrease in OpEx cost. For example, the LCHS of above-ground compressed gaseous storage for a daily and 4-monthly storage cycle length is -$0.33 and -$25.20 per kg of H2, respectively. On the other hand, globally, most green hydrogen is produced by low-carbon electricity primarily based on intermittent solar and wind, and the average levelized cost of hydrogen production ranges from -$3.2 to -$7.7 per kg of H2. Thus, the storage costs are much higher than the generation cost for long-term storage. Storage in salt caverns exhibits the lowest LCHS at -$0.14/kg of H2 for daily storage, followed by above-ground compressed gaseous storage. On the other hand, ammonia has the highest LCHS -$3.51/ kg of H2, followed by methanol -$2.25/kg of H2. These costs are expected to stay relatively high; our CapEx prediction suggests that by 2050 the LCHS of ammonia and methanol could decrease by 20-25%. Furthermore, storage efficiency for ammonia is the lowest at -42%, followed by methanol at -50%, while compressed gaseous shows the highest storage efficiency, at -92%. Overall the analysis shows that the cost of hydrogen storage would need to be significantly reduced for applications in long-term storage or if ammonia/methanol are used (due to, for example, compatibility with existing infrastructure). These insights could increase transparency around the future competitiveness of stationary storage technologies and help to guide research, policy, and investment activities to ensure cost-efficient deployment in a low-emission economy.