# Natural hydrogen

Natural hydrogen (known as white hydrogen, geologic hydrogen, geogenic hydrogen, or gold hydrogen) is molecular hydrogen present on Earth that is formed by natural processes (as opposed to hydrogen produced in a laboratory or in industry).
Modelling suggests that enough natural hydrogen exists to meet humanity's demand for hydrogen for thousands of years, however most of this cannot be extracted economically. Natural hydrogen has been identified in many source rocks in areas beyond the sedimentary basins where oil companies typically operate. As of 2023, only one well of natural hydrogen has been exploited, producing enough gas to generate electricity for a village in Mali.

## History

In Adelaide, Australia in the 1930s, oil well drillers reported finding "vast amounts of high-purity hydrogen." At the time it was viewed as a useless byproduct of the oil drilling industry, and no efforts were made to capture it.
In 1987 in the village of Bourakebougou in Mali, Africa, a worker attempted to light his cigarette next to a certain water well, and the well unexpectedly caught fire. A local entrepreneur soon became interested in the possible economic value of this "burning well" and determined that the flames were produced by natural hydrogen seeping out of the well. A local petroleum company was soon hired to harvest and sell the hydrogen, and as of 2024, the villagers of Bourakébougou village continue to pay for their hydrogen. As of 2023 the Malian hydrogen well remains as the world’s first and only economically successful hydrogen well.
During the 2020s, interest in natural hydrogen has increased and investments have been made to develop natural hydrogen wells in the US, France and Australia. In France, one petroleum company, Française De l’Énergie, has said that it aims to begin extracting hydrogen by 2027 or 2028.

## Natural hydrogen sources

Sources of natural hydrogen include:
* degassing of deep hydrogen from Earth's crust and mantle;
* reaction of water with ultrabasic rocks (serpentinisation);
* water in contact with reducing agents in Earth's mantle;
* weathering – water in contact with freshly exposed rock surfaces;
* decomposition of hydroxyl ions in the structure of minerals;
* natural water radiolysis;
* decomposition of organic matter;
* biological activity
Serpentinization is thought to produce approximately 80% of the world's hydrogen, especially as seawater interacts with iron- and magnesium-rich (ultramafic) igneous rocks in the ocean floor. Current models point towards radiolysis as the source of most other natural hydrogen.

## Resources and reserves

According to the Financial Times, there are 5 trillion tons of natural hydrogen resources worldwide. Most of this hydrogen is likely dispersed too widely to be economically recoverable, but the U.S. Geological Survey has reported that even a fractional recovery could meet global demand for hundreds of years. A discovery in Russia in 2008 suggests the possibility of extracting native hydrogen in geological environments. Resources have been identified in France, Mali, the United States, and approximately a dozen other countries.
In 2023 Pironon and de Donato announced the discovery of a deposit they estimated to be some 46 million to 260 million metric tons (several years worth of 2020s production). In 2024, a natural deposit of helium and hydrogen was discovered in Rukwa, Tanzania., as well in Bulqizë, Albania.

### Midcontinent Rift System

White hydrogen could be found or produced in the Mid-continental Rift System at scale. Water could be pumped down to hot iron-rich rock to produce hydrogen for extraction. Dissolving carbon dioxide in these fluids could allow for simultaneous carbon sequestration through carbonation of the rocks. The resulting hydrogen would be produced through a carbon-negative pathway and has been referred to as "orange" hydrogen.

## Geology

Natural hydrogen is generated from various sources. Many hydrogen emergences have been identified on mid-ocean ridges. Serpentinisation occurs frequently in the oceanic crust; many targets for exploration include portions of oceanic crust (ophiolites) which have been obducted and incorporated into continental crust. Aulacogens such as the Midcontinent Rift System of North America are also viable sources of rocks which may undergo serpentinisation.
Diagenetic origin (iron oxidation) in the sedimentary basins of cratons, notably are found in Russia.
Mantle hydrogen and hydrogen from radiolysis (natural electrolysis) or from bacterial activity are under investigation. In France, the Alps and Pyrenees are suitable for exploitation. New Caledonia has hyperalkaline sources that show hydrogen emissions.
Hydrogen is soluble in fresh water, especially at moderate depths as solubility generally increases with pressure. However, at greater depths and pressures, such as within the mantle, the solubility decreases due to the highly asymmetric nature of mixtures of hydrogen and water.

## Literature

Vladimir Vernadsky originated the concept of natural hydrogen captured by the Earth in the process of formation from the post-nebula cloud. Cosmogonical aspects were anticipated by Fred Hoyle. From 1960–2010, V.N. Larin developed the Primordially Hydridic Earth concept that described deep-seated natural hydrogen prominence and migration paths.