Emergency Response Information: Physisorption (19.6)

Criticality: High
Progress: Addressed, Not Adequately
Score: 20
DOT Relevance: §172 Subpart G

Description of Key Area

This key area pertains to the availability of appropriate information resources needed by first responders to potential emergencies (e.g., accidents) involving hydrogen transportation systems that may utilize physisorption hydrogen storage technology.

Physisorption refers to the process by which hydrogen molecules can be adsorbed into the surface of certain materials such as activated carbon. DOE is sponsoring a large team headed by NREL to research and develop high-physisorption-capacity carbon structures such as nanotubes, which may enable hydrogen storage systems with high gravimetric and volumetric energy densities. In general, hydrogen is adsorbed at low temperatures and desorbed (released) when the temperature is increased. Research is seeking materials with high surface-to-volume ratios that do not require cryogenic temperatures to achieve adequate hydrogen adsorption capacity.

The current DOE research is focused toward on-vehicle hydrogen, but if this R&D is successful, larger-scale adsorbed hydrogen storage systems may be developed (e.g., hydrogen tank truck trailers that transport hydrogen adsorbed on carbon nanostructures). If this type of hydrogen transportation system is used as part of a commercialized hydrogen fueling infrastructure, then emergency response information resources specific to this technology will be needed.

Discussion of Criticality

This key area will be critical if hydrogen fueling infrastructures that utilize physisorption hydrogen storage and transportation systems do in fact evolve. This is because the emergency response requirements may be different from those addressed by currently available information resources, and no known work is currently underway to develop emergency response information specific to hydrogen physisorption packagings (e.g., tank truck trailers containing hydrogen adsorbed in activated carbon nanostructures) or their transportation. The important but unanswered question pertains to the likelihood that such a hydrogen vehicle fueling infrastructure will in fact develop. In this regard, it should be recognized vehicle fueling infrastructure will in fact develop but physisorption based systems may not play a significant role relative to distributed production (i.e., at the fueling station) or delivery via pipeline

Discussion of Progress

Progress toward providing emergency response information resources appropriate to hydrogen physisorption storage packagings and transportation used as part of a hydrogen fueling infrastructure is rated as “Addressed, Not Adequately.” This is because, as discussed above, no specific resources exist at this time.

The DOT ERG2004 lists Activated Carbon, ID Number 1362, and refers to Guide Number 133 (Flammable Solids). The Guidebook also lists Hydrogen, ID Number 1049, and refers to Guide Number 115 (Gases—Flammable, Including Refrigerated Liquids). It might be supposed that the information resources in these two guides is applicable to a tank truck trailer containing a hydrogen physisorption storage system, but it remains to be determined if information resources specifically tailored to this evolving hydrogen storage technology will be needed.

In 2005, the NASFM and DOT’s RITA established the Hydrogen Executive Leadership Panel (HELP). HELP’s mission is “…to bring together emergency responders, government regulators, scientists, consumers and experts from the automotive and energy industries to facilitate a safe and orderly transition to hydrogen and other alternative fuel sources.” HELP will focus on issues involved in training, educating, and mobilizing emergency responders to work with government, industry, and community groups to facilitate and ensure hydrogen transport, storage and distribution, and the safety of vehicles and environs.

Recommendations

It is recommended that research to develop physisorption-based hydrogen storage technology should be monitored. If this R&D succeeds in developing practical and effective hydrogen storage systems and it appears that these systems may be used as part of a commercialized hydrogen vehicle fueling infrastructure (e.g., tank truck trailers containing hydrogen adsorbed in carbon nanostructure media used to transport hydrogen from central production plants to fueling stations), then work to develop appropriate emergency response information resources should be initiated.