Hydrogen
water is currently not economically viable due to the sheer cost of electricity required to allow for hydrogen to be obtained via this method. It is hoped that, with improvements in the technology of electrolysers and also improvements in the technology of renewable energy, making them more efficient and cost effect, electrolysis can become a major method in providing the world with green hydrogen.
Electrolysis equation: 2𝐻 2 𝑂(𝑙) → 2𝐻 2 (𝑔)+𝑂 2 (𝑔)
There are also many hydrogen production methods that are in development such as photoelectrochemical water splitting which produces hydrogen from water using semiconductor materials and energy from the sun. Although hydrogen can be made in numerous methods, each method has a clear drawback. It will take time but with adequate research and technology advancements it is hoped that hydrogen can be produced in a sustainable and efficient manner.
Storage of hydrogen
The storage of hydrogen is yet another challenge. Having an atomic mass of 1, hydrogen is the lightest gas on a per mole basis and also the least dense gas. Although hydrogen has a high specific energy, it has a relatively very low volumetric energy density (energy stored per unit volume) compared to natural gas (methane) and this means that it takes up more space, requiring more storage facilities. A way of tackling this issue is compressing or liquifying hydrogen. Compressing hydrogen is an energy- intensive process which increases costs, and liquifying hydrogen is less practical as hydrogen has an extremely low boiling point of -253 ℃ , which would have to be maintained and which requires a lot of energy and has a high initial and maintenance cost. When hydrogen is compressed in a tank there is also the problem of hydrogen embrittlement. This is a process where hydrogen creeps into the walls of the tank making the tank weak and brittle. This means that tanks must be strong and thick whilst also being specially coated, adding to the cost of storing hydrogen. Scientists have explored the use of material-based storage to store hydrogen. One method is the use of metal hydrides, which are solids, so have a high density and can store more hydrogen while taking up less space. They also can be stored at atmospheric temperatures and pressures, making them cheaper to operate compared to other methods. This method works, as hydrogen is chemically bound to a metal to form a metal hydride and then can be separated to release hydrogen which can then be used to generate energy. Another promising method of storing hydrogen is using ammonia. Hydrogen is used to make ammonia which can easily be stored. When there is a need for hydrogen, the stored ammonia can be cracked under the presence of a catalyst to release the hydrogen which can then be used in fuel cells. Ammonia cracking is still under development due to a major loss in hydrogen when reconverting ammonia back to hydrogen.
Conclusion
It is fair to say that hydrogen can have many applications. In transportation hydrogen fuel cell vehicles offer a clean alternative to traditional combustion engine vehicles, with the emission of zero carbon. In the aviation industry it can help reduce carbon emissions in airplanes and also in the power generation sector it can be used in combination with other sustainable energy sources like wind and solar with
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