Hydrogen is touted as the "ultimate energy source of the 21st century”. Significant in promoting sustainable global economic development, it gradually becomes one of the important drivers for global energy transition.
However, the vast majority of hydrogen produced globally is mainly derived from fossil energy, a process that emits a large amount of carbon dioxide. This type of hydrogen is also known as "grey hydrogen". In this production process, when carbon dioxide is captured, utilized, and stored, it is termed "blue hydrogen", but it is subject to strict constraints on storage conditions. On the other hand, "green hydrogen" produced by electrolyzing water using renewable energy is still very limited due to its high cost, hence it only accounts for less than 4% of total hydrogen production.
In comparison, white hydrogen is naturally generated or exists in the Earth's crust, being a potential and minimally developed clean energy source. It is also referred to as "natural hydrogen", "golden hydrogen", and "geological hydrogen". It possesses at least two major advantages: first, it does not emit carbon dioxide, and second, it does not require water electrolysis for production.
In the past, it was believed that natural hydrogen did not exist because hydrogen would combine with carbon molecules to form hydrocarbons or with oxygen molecules to form hydroxides in the hot rock layers. Since the 1970s, nearly a hundred cases of natural hydrogen seepage and leakage have been discovered worldwide, both on the seabed and on land. In practice, with Russia's discovery of the first white hydrogen deposit in the early 21st century and Hydroma company’s utilization of white hydrogen for power generation in Mali, Africa, people now know more about white hydrogen.
According to current research, several natural processes may lead to the generation of hydrogen in the Earth's crust, but there is still some uncertainty about the scale of formation of natural deposits. Regarding the mechanism of hydrogen generation, there is no consensus yet, but geologists tend to favor two main mechanisms: one is "serpentinization", where water reacts with iron-rich rocks to produce hydrogen gas, and the other is "radiolysis" where deep-seated radioactive elements such as uranium and thorium decay and release radiation that decomposes water molecules to produce hydrogen gas.
The analysis of information tracking by researchers at ANBOUND shows that white hydrogen does have advantages such as not emitting carbon dioxide and being considered as the future petroleum. Yet, even as a potential and minimally developed clean energy source, due to factors such as uncertain reserves, early-stage technology, and high extraction costs, its mass commercial production is unlikely in the short term.
In terms of reserves, according to estimates by geochemist Geoffrey Ellis of the United States Geological Survey (USGS), there may be “tens of billions of tons” of white hydrogen hidden beneath the Earth's surface, while currently only 100 million tons of hydrogen are produced annually. Based on the data on white hydrogen production in 2020, the estimated value for 2020 was (254±91)×109 tons/annum. Additionally, scholars have established a white hydrogen resource potential assessment model based on current data, estimating the in-situ white hydrogen resource volume to range from hundreds of thousands of tons to tens of billions of tons, with an average reaching tens of millions of tons. However, there is still considerable uncertainty.
From a practical perspective, with the exploration efforts of multiple countries worldwide, more and more reserves of white hydrogen are being discovered. Among them, significant natural hydrogen reservoirs have been found in Mali's Bourakebougou, Australia's Yorke Peninsula, Spain's Monzón, the foothills of the Pyrenees in Spain, and the Lorraine basin in France, estimated at 5 million tons, 1.3 million tons, 5 to 10 million tons, 1 million tons, and 6 to 250 million tons of hydrogen respectively. However, whether in overall estimates or individual assessments, white hydrogen reserves are indirectly inferred through investigations of oil and gas or specific geological processes and environments, making it difficult to obtain accurate measurement data, and the actual resource quantity has yet to be confirmed.
Mali is currently the only country in the world actively extracting white hydrogen and benefits from unique geographic conditions. Most other countries are in the early stages of understanding white hydrogen. Some are in the initial phase of white hydrogen exploration, while others, including both nations and enterprises, are just beginning to experiment with white hydrogen extraction. These entities will encounter various challenges and require continuous exploration of innovative technological solutions in areas such as hydrogen exploration, detection and analysis, and leakage management. It is worth noting that white hydrogen accumulations are likely to be very small, offshore, too deep, or in remote areas, which would impose high demands on extraction technology.
The relative cost of extracting white hydrogen remains rather high and that is difficult to change in the short term. In theory, as white hydrogen is a natural renewable energy source, it should be possible to extract it endlessly at a low cost. However, this is not the case in practice. According to estimates, the production cost of white hydrogen is approximately USD 1 per kilogram, while the production cost of green hydrogen is about USD 6 per kilogram. HyTerra, a company conducting natural hydrogen exploration in the United States, believes that production at a cost of USD 1 per kilogram is necessary to compete with natural gas. However, situations similar to Mali's are not common. The deeper the drilling, the higher the purity of white hydrogen. If extensive deposits require deeper drilling, the development cost of white hydrogen may increase rapidly.
Spanish company Helios Aragón states that it can produce natural gas from the vast underground layers at the foot of the Pyrenees Mountains at a cost of EUR 0.75 (approximately USD 0.82) per kilogram. However, achieving a significant reduction in costs would require waiting for several decades, and it is difficult to say whether the cost would be lower than grey or green hydrogen. Helios estimates on its website that by 2060, the cost of producing white hydrogen will be as low as USD 0.50 – USD 1.25 per kilogram, while grey hydrogen will cost USD 0.75 – USD 1.6 per kilogram (currently USD 2 – USD 4 per kilogram), and green hydrogen will cost USD 0.75 – USD 3.25 per kilogram (currently USD 5 – USD 8 per kilogram).
All in all, the global understanding of white hydrogen is still in its early stages, with many unresolved issues in exploration, technology, and application. Therefore, commercial production of white hydrogen is unlikely to be achieved in the short term, and it is even less likely to significantly change the current situation of hydrogen energy and even the new energy supply.
Final analysis conclusion:
White hydrogen, as a potential but minimally developed clean energy source, possesses advantages in hydrogen production pathways such as zero carbon dioxide emissions. That being said, it is unlikely to achieve commercial production in the short term due to factors such as uncertain reserves, early-stage technology, and high extraction costs. Furthermore, it is even less likely to significantly change the current situation of hydrogen energy and the overall new energy supply.
