Hydrogen storage in North America: Status, prospects, and challenges.

Hydrogen (H 2) storage, transport, and end-user provision are major challenges on pathways to worldwide large-scale H 2 use. This review examines direct versus indirect and onboard versus offboard H 2 storage. Direct H 2 storage methods include compressed gas, liquid, and cryo-compression; and indirect methods include physical and chemical adsorption and chemical carriers. In this review paper, we examine these different systems, identifying and discussing challenges related to safe and efficient storage, operating conditions, and applications. Research and development activities related to the economic, safety, and environmental aspects of H 2 storage and transportation in North America are also examined in detail. Technically, pressurized H 2 storage tanks (350 and 700 bar) have not reached the technical onboard applications target of 0.050 kgH 2 /L, where tanks' mass, size, and price are critical limiting factors. High specific energy consumption (SEC) and inevitable boil-off H 2 losses in liquefaction systems reduce their performance. H 2 liquefaction plants can be considered an efficient method for hydrogen storage by reducing energy consumption to less than 6 kWh/kgLH 2 and increasing the capacity of liquefaction systems more than 100 t/day. Various studies are ongoing despite the drawbacks of the irreversibility of H 2 adsorption/desorption operations (100–400 ˚C), successive cooling and heating cycles, and slow refueling in synthesized metal hydride (MH) systems. Insights and recommendations for H 2 storage and transportation in North America suggest short-, medium-, and long-term strategies. Short-term scenarios focus on compressed H 2 in light and heavy vehicles, energy consumption reduction in the provision of liquefied H 2 for ship and truck transport, and using existing natural gas (NG) transmission infrastructures for H 2 /NG mixtures (5–20 vol%). Medium-term scenarios address high-volume H 2 storage for stationary applications using compressed gas storage in upstream and underground tanks, liquid storage in large, insulated tanks, and higher purity H 2 transfer in NG pipelines. Long-term scenarios focus on large-volume subsurface geological storage and basement space use. Additionally, various standards and codes for H 2 storage technologies in North America are categorized. [Display omitted] • This review paper focuses on different H 2 storage strategies and their performance improvement. • Challenges related to safe and efficient storage conditions of H 2 are highlighted. • Various research and engineering potentials of H 2 storage in North America are discussed. • The salt/rock caverns and pipelines for H 2 bulk storage in North America are examined. • Standards/codes and future prospects for H 2 storage technologies in North America are classified. [ABSTRACT FROM AUTHOR]