--- title: "Hydrogen production and storage" subject: "Energy Environment and Society" chapter: 3 key: "semester_7/energy_environment_and_society:hydrogen-production-storage" source: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/hydrogen-production-storage site: BCT Engineering --- # Hydrogen production and storage Energy Environment and Society · Chapter 3: Renewable Energy Sources - Asked in: 2071 Shrawan, 2 marks; year not given - Video: [The Future of Green Hydrogen: Production, Transportation, and Storage](https://www.youtube.com/watch?v=zi_vcr0ArB8) — reneenergy. com - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/hydrogen-production-storage - Whole chapter: https://www.bctengineer.com/md/semester_7/energy_environment_and_society/chapter-3 ## Question Describe the production, storage and transmission of hydrogen fuel (hydrogen energy). ## Short answer Hydrogen is mainly produced by steam methane reforming or electrolysis (green hydrogen with renewable power). Storage options include high-pressure tanks at 3500–7000 bar, cryogenic liquid at -2533 °C, metal hydrides, or chemical carriers. Transmission uses pipelines, tube trailers, or liquid tankers. ## Answer #### Production of hydrogen Hydrogen is an energy carrier, so it must be produced from compounds containing it. 1. **Steam methane reforming (SMR):** CH₄ + H₂O → CO + 3H₂ (700–1000 °C, nickel catalyst), then water-gas shift CO + H₂O → CO₂ + H₂. This is the most widely used method: natural gas gives about two-thirds of world hydrogen, and fossil fuels together (with coal gasification) give about 95% ("grey" hydrogen; with CO₂ capture it is "blue"). 2. **Electrolysis of water:** 2H₂O + electricity → 2H₂ + O₂. Alkaline, PEM or solid oxide electrolysers. If the electricity is from hydro, solar or wind, it is **green hydrogen**. Nepal's surplus hydroelectricity offers this potential. 3. **Coal gasification:** coal + steam → syngas (CO + H₂). 4. **Biomass gasification / biological methods:** gasification of biomass, and photobiological production and fermentation by algae and bacteria. 5. **Thermochemical water splitting** (sulphur–iodine cycle) using high-temperature heat from solar or nuclear. 6. **Photoelectrochemical splitting** using sunlight (research stage). #### Storage of hydrogen Hydrogen has high energy per kg but very low energy per volume, so storage is the main challenge. - **Compressed gas:** steel or composite tanks at 350–700 bar (used in fuel cell vehicles). - **Liquid hydrogen:** cooled to −253 °C in insulated cryogenic tanks; energy intensive and with boil-off losses. - **Solid-state (metal hydrides):** hydrogen absorbed in alloys (for example LaNi₅, MgH₂); safe, compact, but heavy. - **Chemical carriers:** ammonia, methanol, liquid organic hydrogen carriers. - **Underground storage:** salt caverns for large scale. - Adsorption on carbon nanotubes / porous materials (research). #### Transmission (transport) - **Pipelines:** dedicated hydrogen pipelines or blending into natural gas networks. - **Tube trailers** (compressed gas trucks) and **liquid tankers** for medium distance. - **Ships** carrying liquid hydrogen or ammonia for long distance. - Pipeline transport is cheapest for large amounts; hydrogen needs materials resistant to embrittlement. ```text Source(H2O) -> Electrolyser -> Compress/Liquefy -> Store -> Pipeline/Truck -> Fuel cell/engine ``` ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is the reaction of steam methane reforming? A. CH4 + H2O → CO + 3H2 at 700-1000 °C with a nickel catalyst B. 2H2O → 2H2 + O2 C. C + O2 → CO2 D. CO + 3H2 → CH4 + H2O Answer: A. SMR gives about 95% of world hydrogen (grey), followed by water-gas shift. (Key point: Steam methane reforming) 2. When is electrolytic hydrogen called green? A. When the electricity is from hydro, solar or wind B. When the electricity is from coal C. When made from methane D. When stored as liquid Answer: A. Green hydrogen uses renewable electricity for water electrolysis. (Key point: Green hydrogen) 3. Which method stores hydrogen as a liquid? A. Compression at 350-700 bar B. Cooling to -253 °C in cryogenic tanks C. Metal hydrides D. Salt caverns Answer: B. Liquid hydrogen needs -253 °C, is energy intensive and suffers boil-off. (Key point: Hydrogen storage) ## Related in Energy Environment and Society - [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 - [Hydrogen fuel advantages and disadvantages](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Ahydrogen-fuel-adv-disadv) — Energy Environment and Society, chapter 3, asked 3× - [Hydrogen fuel compared with solar](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Ahydrogen-fuel-solar-comparison) — Energy Environment and Society, chapter 3 - [Energy storage technologies and challenges](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Aenergy-storage-technologies-challenge) — Energy Environment and Society, chapter 5, asked 3× - [Forms of energy storage](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Aenergy-storage-forms-four) — Energy Environment and Society, chapter 5 - [Short note: Flywheel energy storage](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Aflywheel-storage) — Energy Environment and Society, chapter 5 ## Related in other subjects - [Hydrogen storage and infrastructure requirements](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Ahydrogen-storage-infrastructure) — Energy Resources, chapter 6 - [Fuel cell voltage, efficiency and hydrogen use](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Afuel-cell-stack-numerical) — Energy Resources, chapter 6 - [Hydrogen production processes](https://www.bctengineer.com/question.md?key=semester_6%2Fenergy_resources%3Ahydrogen-production-methods) — Energy Resources, chapter 6 - [Diesel fuel storage, supply and applications](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-fuel-storage-applications) — Power Plant Equipment, chapter 5