The hydrogen that can be extracted from underground geological formations is called white hydrogen. It is increasingly gaining attention in the context of decarbonization as it can become one of the cleanest energy sources. However, the extraction process is yet to be developed, and broader use would require additional infrastructure.
Natural or white hydrogen, which occurs in the Earth’s crust, can become a clean and renewable energy source. Its production does not require direct use of fossil fuels or electricity, and only water vapor is released when it burns.
White hydrogen is extracted by fracking. The process involves drilling through geological layers and injecting a mixture of water, sand, and chemicals under high pressure to release the gas from the rocks.
However, exploitation of the fuel still poses challenges for the industry. Current options for white hydrogen production are either very expensive or not environmentally safe or sustainable.
White hydrogen could contribute to the decarbonization of steel, aluminum and fertilizer industries and other segments of the economy. It has potential for application in transport, particularly in fuel cell vehicles, which convert hydrogen into electricity.
Natural origin of white hydrogen
Hydrogen is not naturally found in its pure state on Earth but in chemical compounds. The type derived from coal is known as black hydrogen. Gray and blue hydrogen are both produced from natural gas. The difference is that in the blue hydrogen process, carbon capture and storage (CCS) technology is applied to sequester CO2 and prevent it from reaching the atmosphere.
Gray hydrogen is currently the most prevalent in the energy sector, but the solution results in high emissions. It accounts for 900 million tons of CO2 per year, which is roughly equivalent to the global aviation industry.
More greenhouse gas emissions are generated annually in the gray hydrogen production process than in the global aviation industry
Green hydrogen is produced through water electrolysis, using electricity from renewable sources. If the electricity is obtained from nuclear sources, it is referred to as pink hydrogen, which the European Union has partially classified as a sustainable source, along with green hydrogen.
The advantage of white hydrogen is its natural availability. White hydrogen comes from natural deposits in a gaseous state, formed during biological and geological processes.
The largest deposit to date has been discovered in France
Geologists discovered most white hydrogen deposits by accident while searching for fossil fuels.
The discovery of substantial white hydrogen reserves in the northeastern French region of Lorraine has drawn attention recently. It could be the largest deposit uncovered to date.
At a depth of 1,250 meters, the concentration of white hydrogen reaches 20%. Analyses indicated that the share increases as you go deeper. The French research team made the discovery in their quest for methane reserves.
Geologists speculate that the Lorraine deposit could contain up to 46 million tons of white hydrogen, which is more than half of the current global annual production of gray hydrogen. They anticipate that at a depth of 3,000 meters, the hydrogen concentration could exceed 90%.
In addition to France, white hydrogen research is underway in other parts of the world, and geologists suggest that potential reserves also exist in Serbia.
The demand for hydrogen is expected to increase fivefold before the end of 2050.
The Geological Society of America (GSA) forecasted that the demand for hydrogen would quintuple by 2050. Currently, about 100 megatons of hydrogen are used annually for industrial processes.
GSA calculated that white hydrogen could meet at least half of the global demand for sustainable and clean hydrogen by 2100.
Unknowns about extraction and transport costs
Newer applications of hydrogen are driving global demand, including aviation fuel and electricity generation. However, many deposits are too deep underground or in other inaccessible areas, posing challenges to economic feasibility.
Obtaining hydrogen from subsurface reservoirs necessitates the implementation of environmentally sound technological solutions. Given its considerable flammability, it is imperative to enact measures to avoid any interaction between hydrogen and atmospheric oxygen, including the implementation of specialized well-protection protocols.
Storage issues and the lack of pipelines and distribution systems are the main reasons why batteries have outperformed fuel cells in the race for vehicle electrification, as highlighted in a study published in the journal Science.
Storage issues, along with the absence of pipelines and distribution systems, are the primary reasons why batteries have prevailed over fuel cells in the race for vehicle electrification
Although a kilogram of hydrogen holds the same amount of energy as a gallon of gasoline, but its volume is many times bigger. Nonetheless, the authors pointed out that hydrogen has the potential to be a substitute for fossil fuels in vehicles unsuitable for batteries, like trucks, and in vessels and aircraft that can carry large tanks.
Storage under high pressure, up to 700 bar, can address space constraints but comes with increased costs. Hydrogen needs to be cooled to temperatures as low as minus 253 degrees Celsius to transition into a liquid state.