Which hydrogen storage options are currently the most commercially viable?
Click to see answer
Compressed gas and liquid storage.
Click to see question
Which hydrogen storage options are currently the most commercially viable?
Compressed gas and liquid storage.
What is the main topic of the work by T. Autry and colleagues?
Chemical hydrogen storage and control of H2 release from ammonia borane.
Which types of complex hydrides show promise for the future?
Non-transition metal types such as borohydrides, alanates, and amides.
What are some alternative methods for storing hydrogen in liquid form?
NaBH4 solutions, rechargeable organic liquids, or anhydrous ammonia (NH3).
What are the pressure ranges that composite tanks can safely handle?
350-700 bar.
What is the first step in the process of using rechargeable organic liquids to store hydrogen?
An organic liquid is dehydrogenated to produce H2 gas onboard.
How can customers in North America place an order for IEA publications?
Through Turpin Distribution or the OECD online services.
What is a key research question regarding alanates?
Can the pyrophoricity problem be eliminated?
What is the density of cryogenic liquid hydrogen (LH2) at its normal boiling point?
70.8 kg/m³ at –253 °C.
What is the critical pressure and temperature for liquid hydrogen?
Critical pressure is 13 bar and critical temperature is –240 °C.
What is the significance of developing standard testing techniques in hydrogen storage?
To measure H2 uptake and release from carbon samples.
What is illustrated in Figure 15?
A schematic of a rechargeable metal hydride battery.
What is the significance of the acknowledgements section in the document?
It recognizes contributions from experts and financial support for the research.
What is the most common method to store hydrogen in liquid form?
Cooling it down to cryogenic temperatures (–253 °C).
What is the energy density advantage of glass microspheres?
Up to 5 wt.% H2, conformable.
What is a robustness advantage of composite tanks?
They have been extensively tested.
What is a disadvantage of glass microspheres regarding their physical properties?
They are breakable.
What is the final step in the rechargeable organic liquid process?
The H2-depleted liquid is re-hydrogenated and returned to the filling station.
What are the state-of-the-art hydrogen storage technologies mentioned?
Compressed gas, cryogenic liquid, and hydride storage.
What is the focus of G. Sandrock's work on hydrogen storage alloys?
A panoramic overview from a gas reaction point of view.
What is a near-term recommendation for hydrogen storage systems?
Gas storage (composite tanks) in small-scale distributed systems.
What area of research should be intensified regarding complex hydrides?
Basic research on complex hydrides.
How can the low-temperature kinetics and reversibility of alanates be improved?
By adding a catalyst, such as Ti.
Which IEA publications can be downloaded for free?
Books published before January 2004, except for statistics publications.
What is the typical discharge temperature for hydrogen storage mediums used in PEM fuel cells?
Approximately 80 ˚C.
What was the previously reported hydrogen storage capacity of carbon-based materials?
30-60 wt%, which is now considered impossible due to measurement errors.
What is a characteristic of ammonia borane as a chemical hydride?
It can store hydrogen in a solid state but requires off-board regeneration.
What must not be underestimated in all hydrogen storage options?
The safety aspects, particularly with novel hydride storage options.
What specific development should be intensified for compressed hydrogen gas systems?
Reduce compression energy losses, reduce refueling time, and develop 1,000 bar pressure vessels.
What is a novel method for storing hydrogen gas at high pressures?
Using glass microspheres.
What are some advantages of composite tanks for hydrogen storage?
Low weight, commercially available, well-engineered, safety-tested, and no internal heat exchange required.
What are the key technical issues related to vehicular hydrogen storage?
Weight, volume, discharge rates, heat requirements, and recharging time.
What are zeolites known for in hydrogen storage?
They are complex aluminosilicates with engineered pore sizes and high surface areas, functioning as molecular sieves.
What is the address for the International Energy Agency in Paris?
9, rue de la Fédération, 75739 Paris Cedex 15, France.
What is the contact information for Turpin Distribution Services Ltd in the UK?
Tel.: +44 (0) 1767 604960, Fax: +44 (0) 1767 604640.
What is the email address for IEA books?
How can chemical hydrides be handled safely?
In a semi-liquid form, such as mineral oil slurry.
What event did T. Autry's team present their findings?
DOE 2004 Hydrogram Program Review.
What is a long-term recommendation for hydrogen storage systems?
Regenerative complex hydrides in distributed systems.
What is the electrochemical reaction in a rechargeable metal hydride battery?
M + xH2O + xe forms MH + xOH.
What is a key challenge in hydrogen storage systems?
The ability to recharge the system in 3 minutes.
What are the potential issues with NaAlH4?
Pyrophoricity and cost.
What is the goal for borohydrides in terms of desorption temperature?
To achieve desorption at temperatures below 100 °C.
What is a key area of research needed for improving hydrogen storage technologies?
Material embrittlement and development of stronger, lower-cost construction materials.
What is a characteristic feature of clathrate hydrates?
They have H2O cage structures that can contain guest molecules like CH4 and CO2.
Why must organic liquids like methylcyclohexane be handled with care?
They can react violently with strong oxidants, causing fire and explosion hazards.
What is the volume and weight of low-temperature metal hydride storage?
Volume: 55 litres, Weight: 215 kg.
What is a major drawback of composite tanks for hydrogen storage?
The high-pressure requirement.
What are the components involved in the gas phase reaction of a metal hydride?
M + x/H forms MH + heat.
What does the paper provide regarding hydrogen storage technologies?
Key technical details for current technologies and more-novel hydrogen storage technologies.
What are the promising carbons mentioned for high volume production costs?
Graphite nanofibers and nanotubes.
What happens to the dehydrogenated product after it is produced?
It is transported to a central processing plant while refilling the tank with fresh H2-rich liquid.
How much heat removal is required for a typical 5 kg H2-hydride bed?
500 kW.
What is a notable characteristic of borohydrides compared to alanates?
Borohydrides have much higher potential capacities but are less studied.
What is the theoretical maximum storage density of LiBH4?
18.5 wt.% H2.
What is the system density (by weight) target for hydrogen storage in 2010?
6 wt.% H2.
What is the purpose of creating a carbon sample and activation procedure as an international standard?
To provide a consistent reference for researchers in the field.
What are rechargeable hydrides used for in hydrogen storage?
They are used for storing hydrogen in a reversible manner, allowing for repeated use.
What are the potential advantages of solid hydrogen storage compared to gaseous and liquid hydrogen storage?
Lower volume, lower pressure (greater energy efficiency), and higher purity H2 output.
What is a significant drawback of glass microspheres for hydrogen storage?
The high-temperature requirement.
What alternative method can increase the volumetric energy density of gaseous hydrogen?
Cryogas, which is gaseous hydrogen cooled to near cryogenic temperatures.
What is a safety advantage of both composite tanks and glass microspheres?
Both have existing codes & standards and are inherently safe.
What is required for all hydrogen storage systems except gaseous systems?
A heat exchanger.
What types of carbon-based materials have received attention for hydrogen storage?
Nanotubes and graphite nanofibers.
What is a potential benefit of reducing the price of LiBH4?
It could make hydrogen storage more economically viable.
What is one of the important merit factors for hydrogen storage mentioned?
Cost.
What are the three steps involved in using glass microspheres for hydrogen storage?
Charging, filling, and discharging.
What are some examples of chemical hydrides for hydrogen storage?
LiH, MgH2 slurries, CaH2, and LiAlH4.
What is the main advantage of using liquid hydrogen for storage?
High storage density at relatively low pressures.
What is a key focus for developing safe systems in hydrogen storage?
Onboard control of the decomposition reaction.
What are some R&D issues for solid hydrogen storage?
Weight, lower desorption temperatures, higher desorption kinetics, and cost.
Who provided financial support for the hydrogen storage research?
The Research Council of Norway.
What is the cost range for composite tanks in hydrogen storage?
500-600 USD/kg H2.
What should be encouraged in the field of hydrogen storage media?
Truly new and innovative approaches to solid and liquid storage media.
What is the potential of storing hydrogen in solid materials?
It has the potential to become a safe and efficient way to store energy for both stationary and mobile applications.
What is a key research question regarding NaAlH4 catalysts?
Can NaAlH4 catalyst learning be extended to the borohydrides?
What are the three principal forms of hydrogen storage discussed in the paper?
Gas, liquid, and solid.
What are metal oxide frameworks (MOFs) typically made of?
ZnO structures bridged with benzene rings.
What are the gravimetric and volumetric H2 energy storage densities for the ideal reaction?
6.1 wt.% H2 and 43 kg H2/m3.
What is the density of cryogenic liquid H2 storage?
7.5 Wt. % H2.
What are some specific R&D tasks suggested for carbon-based hydrogen storage?
Perform fundamental surface studies, continue theoretical modeling, and study carbon-metal composites for H2 dissociation.
What is a major disadvantage of liquid hydrogen storage?
Boil-off loss during dormancy and the need for super-insulated cryogenic containers.
Which chemical hydride offers the best combination of H2 yield and affordability?
MgH2.
What are some specific R&D tasks needed for glass microspheres?
Development of stronger glasses, low-cost production techniques, coating techniques for H2 permeability optimization, and non-thermal permeability control methods.
What are the two main reversible hydriding reactions in rechargeable metal hydride batteries?
Gas phase reaction and electrochemical reaction.
What organization maintains a large database on rechargeable hydrides?
IEA HIA Annex 17.
What does the metal hydride 'family tree' summarize?
The properties and classifications of various metal hydrides.
What is the most common method to store hydrogen in gaseous form?
In steel tanks.
What is the most studied alanate?
NaAlH4.
Where can all IEA publications be purchased?
On the IEA website.
What is the reversible hydrogen capacity of NaAlH4?
Approximately 4-5 wt. % H2.
What is the main focus of the paper on hydrogen storage?
Vehicular storage, specifically for fuel cell or ICE/electric hybrid vehicles.
What are the main disadvantages of composite tanks?
Large physical volume, high cost (500-600 USD/kg H2), and unresolved safety issues.
What is the target reversible room temperature capacity for the carbon sample in hydrogen storage?
2 wt.% H2.
What is one of the safety concerns associated with composite tanks?
Rapid loss of hydrogen in an accident.
What is the contact information for Turpin Distribution in North America?
Toll free: +1 (800) 456 6323, Fax: +1 (860) 350 0039.
What is the chemical reaction for the dehydrogenation and hydrogenation of methylcyclohexane?
C7H14 (l) ⇔ C7H8 (l) + 3 H2 (g) at T_dehyd = 300-400 °C.
What is the maximum hydrogen storage capacity demonstrated through pure H2 molecular physisorption?
Up to approximately 6 wt.% H2 at cryogenic temperatures.
What is the volume and weight of 35 MPa (350 bar) compressed H2 storage?
Volume: 145 litres, Weight: 45 kg.
What is the maximum hydrogen storage capacity demonstrated through pure atomic H-chemisorption?
Up to approximately 8 wt.% H2, but requires impractically high temperatures (above 400 °C).
What recent progress has been made in borohydrides?
Preliminary progress on LiBH4, particularly on reversibility and destabilization.
What is the desorption temperature for NaBH4?
350 °C.
What is the theoretical maximum storage density of NaAlH4?
7.5 wt. % H2.
What is a significant energy loss percentage during the production of liquid hydrogen?
About 30-40% of the energy is lost.
What is a major problem with glass microspheres for hydrogen storage?
Inherently low volumetric density and high pressure required for filling.
What is a concern regarding gaseous boranes in evolved H2?
They are toxic and could contaminate fuel cell catalysts.
What is the theoretical maximum hydrogen energy storage density for NaBH4 solutions?
10.9 wt.% H2.
What is the status of gaseous hydrogen storage?
Commercially available, but costly.
What is the best option for gaseous hydrogen storage?
C-fibre composite vessels (6-10 wt% H2 at 350-700 bar).
What are the main countries involved in determining hydrogen production and storage R&D priorities?
The United States, Japan, and the IEA.
What discount is offered for PDFs of all IEA books?
20% discount.
What are the four main groups of suitable materials for solid hydrogen storage?
Carbon and other high surface area materials, H2O-reactive chemical hydrides, thermal chemical hydrides, and rechargeable hydrides.
How does Mg(AlH4) compare to NaAlH4 in terms of reversibility?
Mg(AlH4) is not nearly as reversible as NaAlH4.
What does the paper identify regarding hydrogen storage options?
The advantages and disadvantages of various hydrogen storage options and the main technological gaps.
What type of compressor is being considered for hydrogen storage development?
Hydride-type compressors utilizing waste heat or solar energy.
What is the main R&D question regarding clathrate hydrates?
Whether they can be engineered to reversibly store high levels of H2 near room temperature.
What are some specific R&D tasks mentioned for improving organic liquid hydrogen storage?
Developing low-temperature dehydrogenation systems, optimal metal catalysts, and the re-hydrogenation process.
What is the theoretical potential storage density for H2 O-reactive chemical hydrides?
Around 5-8 wt.% H2.
What happens to glass microspheres at ambient temperatures?
They slowly leak hydrogen.
What is the main advantage of using NaBH4 solutions for hydrogen storage?
Safe and controllable onboard generation of H2.
What is a challenge with borohydrides?
They are generally too stable and not as reversible as alanates.
What is a suggested moderate approach for carbon-based hydrogen storage research?
Continue research for a limited additional time, focusing on fundamental surface studies and theoretical modeling.
What is the target refueling time for hydrogen storage systems?
3 minutes.
How does the energy density of liquid hydrogen compare to that of borohydride solutions and organic liquids?
Liquid hydrogen has a theoretical maximum of 100 wt.% H2, while borohydride solutions have 10.9 wt.% and organic liquids have 6.1 wt.% H2.
What operational challenge is associated with glass microspheres?
The need to supply heat at temperatures higher than those available from PEM fuel cells (70-80 °C).
What are the advantages of using glass microspheres for hydrogen storage?
Inherently safe storage at relatively low pressure and suitability for conformable tanks, leading to low container costs.
What does Table 3 in the paper show?
Practical hydrogen storage system and media targets for fuel cell vehicles.
What percentage of hydrogen can be achieved in practical hydrogen systems from the theoretical gravimetric density of LH2?
Only 20 wt.% H2.
What is a significant challenge in the infrastructure for liquid hydrogen storage?
It requires a safe and well-organized industrial infrastructure due to toxic substances and extreme temperatures.
What is a key R&D task for processing spent hydroxide back into hydride?
Lowering the cost of the energy-intensive process.
What is the demonstrated storage density of hydrogen in glass microspheres?
5.4 wt.% H2.
What is the status of solid hydrogen storage?
Very early development with many R&D questions.
At what pressure and temperature are hollow glass spheres filled with hydrogen?
350-700 bar and approximately 300 °C.
How do mesoporous scaffolds affect decomposition kinetics?
They greatly increase the decomposition kinetics.
What R&D is needed for glass microspheres?
Reducing H2 liberation temperatures to less than 100 °C.
What is the most-developed option in solid hydrogen storage?
Metal hydrides (potential for > 8 wt.% H2 and > 90 kg/m3 H2-storage capacities at 10-60 bar).
What is the liberation temperature for hydrogen mentioned in the paper?
150°C.
What must be done to the reaction product NaBO2 in NaBH4 solutions?
It must be regenerated back to NaBH4 off-board.
What is the decomposition temperature for NH4BH4?
< 250 °C.
What reaction is used for hydrogen storage in NaBH4 solutions?
NaBH4 (l) + 2H2O (l) → 4H2 (g) + NaBO2 (s).
What is the required cost reduction for NaBH4 regeneration to make it viable for vehicles?
From 50 USD/kg to less than 1 USD/kg.
What is one of the main R&D tasks related to decomposition temperatures?
To find out if decomposition temperatures can be lowered to < 100 °C.
What are some R&D issues for liquid hydrogen storage?
High liquefaction energy, dormant boil off, and safety.
