---
title: "Hydrogen storage and infrastructure requirements"
subject: "Energy Resources"
chapter: 6
key: "semester_6/energy_resources:hydrogen-storage-infrastructure"
source: https://www.bctengineer.com/q/semester_6/energy_resources/hydrogen-storage-infrastructure
site: BCT Engineering
---

# Hydrogen storage and infrastructure requirements

Energy Resources · Chapter 6: Non conventional forms of energy and batteries

- Asked in: year not given, 5 marks
- Video: [Why Hydrogen Needs 700 Bar Just to Work](https://www.youtube.com/watch?v=3aEj5Ne7GPA) — reneenergy. com
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/energy_resources/hydrogen-storage-infrastructure
- Whole chapter: https://www.bctengineer.com/md/semester_6/energy_resources/chapter-6

## Question

Explain the methods of storing hydrogen. Describe the infrastructure needed for production, storage, transport and utilisation of hydrogen, and mention the safety concerns.

## Short answer

Compressed gas (350–700 bar) and cryogenic liquid (−253°C) store H2; metal hydrides and ammonia are alternatives. Infrastructure includes production (electrolysis/reforming), compression, high-pressure tanks, pipelines/tube trailers, dispensing stations. Safety: flammable (4–75% in air), low ignition energy, embrittlement, invisible flame; requires detectors, ventilation.

## Answer

Hydrogen has a high energy per kg (120 MJ/kg lower heating value) but a very low density (0.084 kg/m³ at normal conditions), so storage is the main difficulty.

#### Storage methods

| Method | Condition | Remark |
|---|---|---|
| Compressed gas | 350–700 bar in carbon-fibre tanks | Most used in vehicles; about 40 kg/m³ at 700 bar |
| Liquid hydrogen | −253 °C in insulated tanks | 71 kg/m³; 30 % of the energy is lost in liquefaction and boil-off occurs |
| Metal hydrides | H₂ absorbed in alloys (LaNi₅, MgH₂) | Safe, compact but heavy, low mass percent |
| Chemical carriers | Ammonia, methanol, liquid organic carriers | Easy to carry, need a reaction to release H₂ |
| Underground | Salt caverns, depleted gas fields | Large seasonal storage |

#### Infrastructure
- **Production:** electrolysers with renewable power, SMR or gasification units; water supply; purification.
- **Compression and storage:** compressors, high-pressure tanks, cryogenic tanks, cavern storage.
- **Transport:** tube trailers, liquid tankers, dedicated pipelines or blending into natural gas pipes (limit about 10–20 %).
- **Utilisation:** refuelling stations for fuel cell vehicles, fuel cell power systems, hydrogen burners, industry (ammonia, refining, steel).
- **Standards:** codes, trained staff, leak detectors.

#### Safety
Hydrogen is colourless and odourless, leaks easily through small gaps, has a wide flammable range (4–75 % in air), very low ignition energy (0.02 mJ) and burns with an invisible flame; it also embrittles steels. So good ventilation, hydrogen sensors, flame detectors and approved materials are required.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Why is storage the main difficulty for hydrogen?
   A. It has low energy per kg
   B. It has high energy per kg but very low density (0.084 kg/m3)
   C. It is too dense
   D. It cannot be compressed
   Answer: B. Hydrogen has 120 MJ/kg but occupies a large volume at normal conditions. (Key point: Why storage is difficult)

2. What is the main drawback of liquid hydrogen storage?
   A. It needs 700 bar
   B. About 30 % of the energy is lost in liquefaction and boil-off occurs at -253 C
   C. It is heavy metal alloy storage
   D. It cannot be used in tanks
   Answer: B. Liquefaction at -253 C is energy-costly and boil-off occurs. (Key point: Liquid hydrogen)

3. Which is a typical compressed hydrogen storage for vehicles?
   A. 1 bar steel cylinders
   B. 350-700 bar carbon-fibre tanks
   C. Salt caverns
   D. Metal hydrides at -253 C
   Answer: B. Vehicles mostly use 350-700 bar carbon-fibre tanks. (Key point: Compressed gas storage)

4. Which property makes hydrogen a safety concern?
   A. It is a dense, visible gas
   B. Wide flammable range (4-75 %), very low ignition energy and an invisible flame
   C. Narrow flammable range
   D. It is strongly smelly
   Answer: B. Hydrogen is odourless, leaks easily and ignites readily, so sensors and ventilation are needed. (Key point: Safety concerns)

## Related in Energy Resources

- [Hydrogen production processes](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Ahydrogen-production-methods) — Energy Resources, chapter 6

## Related in other subjects

- [Hydrogen production and storage](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Ahydrogen-production-storage) — Energy Environment and Society, chapter 3
- [Electrochemistry basics, hydrogen production](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Aelectrochemistry-hydrogen-production) — Energy Environment and Society, chapter 3
- [Safety and serviceability requirements](https://www.bctengineer.com/question.md?key=semester_6%2Fdesign_of_steel_and_timber_structure%3Asafety-serviceability-requirements) — Design of Steel and Timber Structure, chapter 3, asked 2×