Green hydrogen holds great promise for the renewable energy sector and ongoing efforts to decarbonize the economy. Given the abundance of hydrogen most abundant element in the universe, intensive research is underway to design extraction and processing methods. This hydrogen is classified as green hydrogen when carried out using renewable sources such as solar or wind energy.
Traditionally, electrolysis of water, which splits hydrogen molecules, is the dominant method. However, alternative strategies are emerging to accelerate hydrogen production. Among these methods is air electrolysis, also called DAE (Direct Air Electrolysis), which has proven itself in the extraction of hydrogen.
How to get green hydrogen from air
Conventional water electrolysis, a process that separates oxygen from hydrogen using an electric current, relies on two key elements: fresh water source and supply of energy for optimal execution. In regions with only access to salt water, such as coastal areas, sea water desalination becomes a prerequisite before electrolysis can take place, leading to increased production costs. Additionally, many regions with high solar energy potential are characterized by arid or semi-arid conditions with limited water resources.
To circumvent these challenges, an innovative approach is to harness renewable energy resources wherever they are available, regardless of the availability of fresh water. In light of this, the concept becomes clear: the atmosphere, a ubiquitous and easily accessible resource, can serve as a solution. This rationale underlies a recent revolutionary technology, highlighted in the scientific journal Nature, which uses direct electrolysis to extract green hydrogen directly from the air.
In a series of experiments carried out by the research team using direct air electrolysis modules, stable production of green hydrogen from the atmosphere was maintained for twelve consecutive days, powered exclusively by the electricity produced from Solar panel panels and wind turbines. But what exactly does this technology involve? DAE modules rely on water but supply it from atmospheric humidity, similar to the method described in This item on home drinking water dispensers.
With the The Earth's atmosphere is home to 12.9 trillion tons of water at any given time.exploiting this vast reservoir thanks to innovative technologies such as “air harps” mentioned in a previous article could revolutionize access to drinking water. Additionally, a similar approach is promising for producing green hydrogen from the atmosphere.
The experiment involved stacking five DAE modules designed to capture atmospheric water, store it, and perform electrolysis using solar energy. The result was the production of 1,490 milliliters of high purity hydrogen in a single day. Notably, even after eight months without maintenance, the modules retained their efficiency almost intact.
Researchers say this level of efficiency is unprecedented and marks one of the first technologies capable of exceeding the 20% efficiency threshold for solar-hydrogen conversion set by the US Department of Energy. Therefore, the deployment of these devices, capable of capturing atmospheric humidity even in arid conditions like the Sahel desert in Africa, presents an opportunity to generate green hydrogen from the air in developing countries. facing a shortage of fresh water.
What is green hydrogen used for?
Green hydrogen has many advantages, with its simple storage capabilities and impressive calorific value. Its versatility extends to fuel cells and industrial applications, similar to the use of liquefied natural gas. Among its notable applications, we find:
- Integration into industrial processes and land transport, illustrated by the Power to Green Hydrogen Majorca project.
- Aviation deployment for long distance flights.
- Promotion of sustainable urban mobility, including cars and even hydrogen bikes.
- Facilitating renewable energy storage from sources such as solar and wind.
- Installation of hydrogen boilers for residential use.
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