Angela Symons
Sun, 5 November 2023
Hydrogen has been touted as the ‘fuel of the future’. It only emits heat and water when it burns, making it an appealing alternative to fossil fuels.
But the majority of hydrogen production currently relies on gas or coal, in processes that emit a lot of CO2.
‘Green’ hydrogen, which is made using renewable energy, offers a promising - but expensive - alternative. So what if there was a way to cut out these production processes altogether?
Earth holds vast supplies of natural hydrogen that could be extracted from the ground.
A huge discovery of this so-called ‘white’ hydrogen in France earlier this year sparked excitement that it could become a clean, cheap and renewable energy source.
Switzerland soon joined the search, finding natural hydrogen in the Graubünden canton in spring. In summer, the country began probing rocks in Valais for further deposits.
Could white hydrogen hold the key to safe and clean energy, and why is it only just being explored?
What is white hydrogen?
Hydrogen is the most abundant chemical element on Earth and occurs naturally in everything from water to plants.
Until recently, however, significant quantities of hydrogen gas in its pure form were not thought to be present within the earth.
An accidental discovery was made in Mali in 2012. A borehole drilled for a well decades earlier was found to be emitting almost pure natural hydrogen.
Since then, geologists have increasingly been experimenting with extracting supplies of this natural gas - thought to form through water-mineral reactions - from beneath the earth’s surface.
Unlike fossil fuel stores, which take millions of years to form, natural or ‘white’ hydrogen is continuously replenished.
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Is white hydrogen the future of safe and clean energy?
It isn’t yet clear exactly how white hydrogen deposits form, and whether they are commercially exploitable.
Startups and scientists are exploring this possibility - with some promising results.
“The earth has many locations where the right conditions co-exist to naturally produce and accumulate hydrogen, which can then be extracted for societal use,” Dr Michael Webber, a professor in energy resources at the University of Texas, Austin, USA, tells Euronews Green.
“The good news is that by letting the earth do the work for us, this source of hydrogen is likely much cleaner to produce than current methods of gasifying coal, reforming methane, or electrolysing water.”
Although most natural hydrogen is likely to be found in unreachable offshore locations, deposits have been discovered in Australia, eastern Europe, France, Oman, Spain and the US, as well as in Mali, West Africa.
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In May, a large deposit of natural hydrogen was accidentally discovered in the Lorraine region of France. A research team from the University of Lorraine’s GeoRessources Lab, France’s National Centre for Scientific Research (CNRS) and energy producer La Française de l'Energie found it while testing methane levels in the soil.
They are currently drilling deeper to find out exactly how much hydrogen there is, but estimate that there could be around 46 million tonnes - the equivalent of more than half of the world’s current annual production of grey hydrogen - according to CNRS.
Meanwhile in northeast Spain, exploration company Helios Aragón says it has located a reservoir of over one million tonnes of hydrogen, which it aims to start drilling in 2024.
It shows promise as a cheap alternative to green hydrogen, which currently costs roughly €5 per kilogram. White hydrogen costs just €0.50 per kilogram, news and research outlet Science reports.
What are the problems with hydrogen energy?
White hydrogen may not be a silver bullet for the energy crisis, however.
Some scientists say the lack of data on hydrogen leaks and the potential harm they could cause is an issue for the emerging industry.
If hydrogen seeps into the atmosphere, it can reduce the concentration of molecules that destroy the greenhouse gases there, counteracting its environmental benefits.
With a lack of technology to monitor hydrogen leaks, this could be a major blind spot.
“As with other sources of hydrogen, [natural hydrogen] needs to be handled with care to reduce safety risks and avoid leaks,” says Dr Webber.
But it may not be as significant an environmental risk as some believe.
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“Our research at UT Austin, which was presented [on Wednesday] at the ASME IMECE conference in New Orleans, concludes that the indirect global warming impact of fugitive hydrogen emissions is actually quite small compared to other life cycle greenhouse gas impacts, so the greenhouse risks from unwanted hydrogen leaks is minor.”
Leaks aren’t the only concern when transporting hydrogen, though. It takes up a lot of space in gas form and requires a temperature of -253°C to be liquified, which could be prohibitively expensive.
There is also a lack of pipelines and distribution systems for hydrogen. The fossil fuel industry hopes that it could eventually move through existing infrastructure, such as gas pipelines. However, scientists say that hydrogen can corrode metal pipes and lead to cracking.
Not only are hydrogen molecules much smaller and lighter than those in methane, making them harder to contain, but they are also far more explosive than natural gas - raising safety concerns.
These are some of the reasons heat pumps and battery powered EVs won out over hydrogen-based alternatives, according to Science.
The fuel could be better suited to heavy-duty vehicles which can’t easily use batteries, such as trucks, ships and planes, as well as the steel industry and chemical processes like fertiliser production.
New approach to water electrolysis for green hydrogen
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IDENTIFICATION OF TRENDS AND DESIGN OF BALANCED CATALYSTS WITH COMPOSITION-SPECIFIC ANALYSIS
view moreCREDIT: POSTECH
Originally, the term "Sherpa" denoted a hill-tribe of Tibetan descent, but it has since become synonymous with guides on Mount Everest, the world's highest and most rugged mountain. Much like these Sherpas, research into the demanding task of developing catalysts for hydrogen production is making substantial progress and has earned recognition as the featured cover article in a prominent international journal.
Professor Yong-Tae Kim from the Department of Materials Science and Engineering and the Graduate Institute of Ferrous & Eco Materials Technology, and Kyu-Su Kim, a doctoral student from the Department of Materials Science and Engineering at Pohang University of Science and Technology (POSTECH), collaborated on a research project that offers a promising direction for the future development of catalysts for water electrolysis. Their study has garnered considerable academic attention and was showcased as the cover article in ACS Catalysis, an international journal in the field of chemistry.
Water electrolysis, a method for producing hydrogen from the abundant resource of water, emerges as an environmentally friendly technology that produces no carbon dioxide emissions. However, this process faces limitations due to its reliance on precious metal catalysts such as iridium (Ir), rendering it economically unfeasible. Researchers are actively exploring the development of catalysts in the form of metal alloys to address this challenge.
In the field of water electrolysis catalysis research, the primary catalysts under scrutiny are iridium, ruthenium (Ru), and osmium (Os). Iridium, despite its high stability, exhibits low activity and comes at a steep price. Conversely, ruthenium displays commendable activity and is a more cost-effective option compared to iridium, although it lacks the same level of stability. Osmium, on the other hand, readily dissolves under various electrochemical conditions, leading to the formation of nanostructures with an expanded electrochemical active surface area, thereby enhancing geometrical activity.
Initially, the research team developed catalysts using both iridium and ruthenium. By combining these metals, they successfully preserved the excellent attributes of each, resulting in catalysts that demonstrated improvements in both activity and stability. Catalysts incorporating osmium exhibited high activity due to the expanded electrochemical active surface area achieved through nanostructure formation. These catalysts retained the advantageous properties of iridium and ruthenium.
Subsequently, the team expanded their experimentation to include all three metals. The results showed a moderate increase in activity, but the dissolution of osmium had a detrimental effect, significantly compromising the structural integrity of iridium and ruthenium. In this series, the agglomeration and corrosion of nanostructures were accelerated, leading to a decline in the balance of catalytic performance.
Based on these findings, the research team has proposed several avenues for further catalyst research. First and foremost, they stress the need for a metric that can simultaneously evaluate both activity and stability. This metric, known as the activity-stability factor, was initially introduced by Kim's research group in an international journal in 2017.
Additionally, the team advocates for the retention of superior catalyst properties even after the formation of nanostructures, in order to enhance the electrochemical active surface area of the electrocatalyst. They also highlight the importance of carefully selecting candidate materials that can effectively synergize when alloyed with other metals. The essence of this study lies not in presenting specific outcomes like the development of new catalysts, but rather in offering essential considerations for catalyst design.
Professor Yong-Tae Kim, who spearheaded the research, remarked, "This research marks the beginning of our journey, not the conclusion." He shared his vision by stating, "We are dedicated to the continuous development of efficient water electrolysis catalysts based on the insights gained from this research."
The study received support from the Future Materials Discovery Program of the National Research Foundation of Korea.
JOURNAL
ACS Catalysis
ARTICLE TITLE
Deteriorated Balance between Activity and Stability via Ru Incorporation into Ir-Based Oxygen Evolution Nanostructures
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