*Most countries of the world seek to change their energy policy to reduce carbon dioxide emissions (pollution), that is, protect the environment and climate, in addition to obtaining permanent sources of energy. Hydrogen is an ideal source of clean energy, and it is used in many industrial fields and as a fuel in the field of transportation, and when burned, it doesn't release any damaging gases into the atmosphere, such as carbon dioxide. What makes this element very important as an alternative energy is its abundance, as it is the most abundant element in the universe.* 

![](https://images.ecency.com/DQmQSyBCSz7yS9dk6Der7V4cKyCQYMHy3hNpXNfgccg6a62/image.png)
[Hydrogen recharging station in Japan- By Iwatani in Ariake](https://en.wikipedia.org/wiki/File:Hydrogen_recharging_station,_by_Iwatani_in_Ariake_3.jpg)

*Hydrogen gas is often produced from the electrolysis of water, and the challenge here lies in the method of electrical power generation used in this process, as manufacturers and researchers seek to rely on renewable energy sources such as wind energy, as well as find new scientific methods to reduce the cost of production.*

The production of hydrogen by electrolysis of high temperature water vapor "HTE":
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One of the very important conditions for hydrogen production and reliance on it as an energy alternative is that the production process be highly efficient and low in cost. Conventional water electrolysis plants ([electrolysis of water](https://en.wikipedia.org/wiki/Electrolysis_of_water) at ambient temperature) are able to achieve a total yield ranging from 25 to 28 percent. While the process of electrolysis of water vapor at high temperatures is more efficient (40 to 50 percent) depending on the main source of energy.

![](https://images.ecency.com/DQmTsZwVAcdJJwup1HFpx7CqioobjdDKCdeWXcJRRpQm1MF/image.png)
[Diagram of high temperature electrolysis (HTE)- Drawn by Grimlock](https://commons.wikimedia.org/wiki/File:High-temperature_electrolysisfr.png?uselang=fr)

Part of the energy that the water molecules need to break down will be provided by heat and thus the cost will be lower because heat is cheaper than electricity. In addition, the reaction efficiency is better at high temperatures, due to these very important factors. The electrolysis technique of water vapor is used at high temperatures ranging between 700 and 900 ° C to produce hydrogen from the dismantling of water molecules, with oxygen obtained as a byproduct of this reaction.










References:
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- [W. Doenitz, R. Schmidberger, E. Steinheil, R. Streicher. Hydrogen production by high temperature electrolysis of water vapour. International Journal of Hydrogen Energy. Volume 5. Issue 1,1980. Pages 55-63. ISSN 0360-3199](https://www.sciencedirect.com/science/article/abs/pii/0360319980901147)

- [F.J. Salzano, G. Skaperdas, A. Mezzina. Water vapor electrolysis at high temperature: Systems considerations and benefits. International Journal of Hydrogen Energy,
Volume 10, Issue 12,1985. Pages 801-809. ISSN 0360-3199](https://www.sciencedirect.com/science/article/abs/pii/0360319985901685)

-  "Progress in SOFC technology development at fuel cell energy," in Proceedings of the 20th Annual Solid Oxide Fuel Cell (SOFC) Project Review Meeting, Washington, DC, April 30, 2019.


- [Jean-Pierre Py (AREVA NP) – Alain Capitaine (EDF)- HYDROGEN PRODUCTION BY HIGH TEMPERATURE ELECTROLYSIS OF WATER VAPOUR AND NUCLEAR REACTORS](https://www.cder.dz/A2H2/Medias/Download/Proc%20PDF/PARALLEL%20SESSIONS/%5bS05%5d%20Production%20-%20Water%20Electrolysis/15-06-06/414.pdf)

- [Les matériaux au cœur du processus d'innovation - N°59- Clefs CEA No 59 – Parution : Eté 2010](https://www.cea.fr/multimedia/Pages/editions/clefs-cea/materiaux-au-coeur-processus-innovation.aspx)