CG: n
CT: Blue hydrogen refers to hydrogen derived from natural gas, which is a fossil fuel, however, most (albeit not all) the CO2 emitted during the process would be captured and stored underground (carbon sequestration) or bound in a solid product (such as bricks) and utilized. This is called carbon capture, storage and utilisation (CCSU).
One process for achieving this is called steam methane reforming (SMR). This mixes natural gas with very hot steam, in the presence of a catalyst, where a chemical reaction creates hydrogen and carbon dioxide and carbon monoxide. An improvement of this process, auto-thermal reforming (ATR) combines the steam reforming reaction and fuel oxidation into a single unit. This process is more efficient and is able to capture more of the CO2 emitted in course of production. When considering the CO2 emission reduction potential of “blue” hydrogen, it is important to acknowledge the importance of tackling methane leakage upstream of the hydrogen production plant. This should be done by applying a strict life-cycle assessment when determining the CO2 emissions associated with its production.
S: HE – https://hydrogeneurope.eu/in-a-nutshell/ (last access: 25 January 2024)
N: 1. – blue (adj): “of the color of the clear sky,” c. 1300, bleu, blwe, etc., “sky-colored,” also “livid, lead-colored,” from Old French blo, bleu“pale, pallid, wan, light-colored; blond; discolored; blue, blue-gray,” from Frankish *blaoor some other Germanic source, from Proto-Germanic *blæwaz (source also of Old English blaw, Old Saxon and Old High German blao, Danish blaa, Swedish blå, Old Frisian blau, Middle Dutch bla, Dutch blauw, German blau “blue”).
– hydrogen (n): 1791, from French hydrogène, coined 1787 by G. de Morveau, Lavoisier, Berthollet, and Fourcroy from Greek hydr-, stem of hydor “water” + French -gène “producing”. So called because it forms water when exposed to oxygen. Nativized in Russian as vodorod; in German, it is wasserstoff, “water-stuff.” An earlier name for it in English was Cavendish’s inflammable air (1767). Hydrogen bomb first recorded 1947; shortened form H-bomb is from 1950.
2. Hydrogen derived from natural gas through the process of steam methane reforming (SMR), in which most of the carbon dioxide emissions produced are then captured and stored underground using Carbon Capture, Utilization and Storage (CCUS) technology leaving nearly pure hydrogen.
3. Due to the differences in CO2 emissions that can occur in the production of “blue” hydrogen (depending on upstream methane emissions and the production technology used), the term itself can be considered too broad. Instead, when referring to hydrogen produced from natural gas, it is more accurate to refer to it using the actual GHG footprint associated to its production.
4. In order to differentiate between different production methods of hydrogen the same molecule was assigned different colours. Just as energy suppliers offer grey and green electricity, companies also produce grey and green hydrogen.
Green hydrogen is produced by splitting water molecules (H2O) into hydrogen (H2) and oxygen (O2) by electrolysis. Only when the electricity required for this comes from renewable sources is it called green hydrogen.
With grey hydrogen, natural gas (CH4) and steam (H2O) are split into hydrogen (H2) and carbon dioxide (CO2). At present, the carbon dioxide released in the production of grey hydrogen escapes into the air. Storing this greenhouse gas underground prevents additional global warming. The hydrogen gas produced in this way is called blue hydrogen.
In principle, the production method of blue hydrogen is no different to grey hydrogen. The industrial ‘steam methane reformers’ (SMR) or ‘auto thermal reformers’ (ATR) that currently produce grey hydrogen can also produce blue hydrogen. However, more efficient systems for separating synthesis gas are now available. Such as our SEWGS technology, which not only saves costs, but also removes more CO2.
5. Cultural interrelation: We can mention the book Blue Hydrogen & Green Hydrogen: Futuristic Fuels (2002) by Prof Pramod Kumar Mallya and Rekha M.
S: 1. Etymonline – https://www.etymonline.com/search?q=blue, https://www.etymonline.com/search?q=hydrogen (past access: 25 January 2024). 2. ATCO – https://gas.atco.com/content/dam/web/projects/projects-overview/hydrogen/hydrogen-types.pdf (last access: 25 January 2024); HE – https://hydrogeneurope.eu/in-a-nutshell/ (last access: 25 January 2024). 3 HE – https://hydrogeneurope.eu/in-a-nutshell/ (last access: 25 January 2024). 4. TNO – https://www.tno.nl/en/technology-science/technologies/blue-hydrogen/ (last access: 25 January 2024). 5. Amazon – https://www.amazon.com/Blue-Hydrogen-Green-Futuristic-overview-ebook/dp/B09SWWTTH6 (last access: 25 January 2024).
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CR: alternative energy sources, biomass energy, carbon, coal, electricity, emission reduction, energy transition, green hydrogen, grey hydrogen, hybrid car, hydrocarbon, hydrogen, hydrogen refuelling station, just transition, natural gas.
