AS the world’s supply of fossil fuels continues to dwindle, corporations and governments have turned their attention to searching for replacements for coal, oil and gas. We have long been familiar with renewable, green energy sources like solar, wind or hydroelectric power. Looming silently in the background of all these potential solutions is hydrogen gas.

Hydrogen, the most fundamental element in the universe, is the origin of all solar energy. As well as providing us with heat and light through nuclear fusion processes in the sun’s core, hydrogen has many uses for energy production and storage.

Like electricity, hydrogen is an “energy vector” — an energy-rich substance that facilitates the translocation and/or storage of energy to be released at a later time or at a distance from the primary capture site.

In the sun, the energy released from hydrogen is through nuclear energy released in fusion. However, hydrogen is also a direct energy source through combustion. Here, it has the advantage that it has no emissions beyond its product water. Furthermore, it has a very high specific energy density — generating more heat when combusted than petrol.

Hydrogen gas has many potential uses, already realised to varying degrees. Vehicles can be powered with hydrogen fuel cells. Hydrogen can be burnt to heat homes or power them with electricity; it can also be stored locally.

It can power portable electronics or be used to process chemicals. But the viability of hydrogen as an energy source on a global scale is, however, severely limited at present. Despite being the most abundant element in the universe, hydrogen very rarely exists on Earth in its elemental form (H2): it is so light it has a tendency to escape into space once it is in the atmosphere.

Current methods of hydrogen production are costly, difficult and often rely on fossil fuels, which somewhat defeats the purpose of hydrogen gas being a replacement.

“Greener hydrogen” production methods have been developed, which rely on renewable solar, wind or hydroelectric energy to split water into its hydrogen and oxygen atoms.

As we have written about before, whether this process becomes a major player in global energy systems is the subject of billions of dollars of investment in plants currently being constructed worldwide.

But hope for a “clean,” mined, hydrogen gas source remains alive. The village of Bourakebougou in Mali currently gets its electricity from a nearby hydrogen field. The natural hydrogen was discovered during a water drilling operation in 1987, but the wider underground system remained unexplored until a Canadian corporation then known as Petroma (now Hydroma) began surveying for hydrocarbons in the region.

The rediscovery of the natural hydrogen gas led to the development of a pilot project that supplied Bourakebougou with electricity solely from hydrogen combustion for almost a decade. The huge advantage of this hydrogen reservoir is that it appears to be progressively recharged in hydrogen-rich gas in a timeframe that keeps up with extraction, unlike fossil fuels, which take up to millions of years to form.

This remarkable refilling has prompted global interest in how it happens. A 2020 review paper by geologist Viacheslav Zgonnik emphasises that natural hydrogen can be formed by several different geochemical processes.

For example, when rocks rich in certain minerals (olivine and pyroxene) interact with water, oxygen from the water is captured to make rust (iron oxide), releasing hydrogen gas.

This natural underground rusting process is typically thought of as occurring in oceanic crust, but the prevalence of the reaction in regions of ancient continental crust may have been overlooked.

This has prompted renewed interest in the potential of hydrogen reservoirs in South Australia, which hosts continental crust that is billions of years old; in the 1930s, two wells were drilled to search for oil and reported discovering hydrogen gas. Currently, two companies have been granted exploration licences to search for hydrogen across the state.

But as the lightest chemical element, without a seal to contain and allow it to accumulate, hydrogen is likely to seep away into surrounding rocks or be released into the air. Researchers have instead been fascinated by the processes that stop that release and allow the gas to accumulate.

A 2023 study published in Nature aimed to understand the geological characteristics of an exploitable hydrogen reservoir, using the Bourakebougou example as a case study. It concluded that the hydrogen is prevented from escaping by numerous intrusions of dolerite, an igneous rock that forms when magma cools close to the Earth’s surface.

These intrusions are long, flat bodies of rock known as sills. Currently, it remains to be seen whether the Bourakebougou field has unique conditions for hydrogen storage and extraction, or whether these geological conditions are replicated elsewhere.

As a new extractive process in a capitalist world, the exploitation of hydrogen gas reserves should be scrutinised carefully. Extraction of hydrogen would likely lead to the leakage of hydrogen into the atmosphere in larger amounts than is natural.

Hydrogen reacts with a compound called hydroxyl to create ozone, which is a greenhouse gas in the lower atmosphere. Hydroxyl breaks down methane in the atmosphere, meaning its loss through reaction could worsen the greenhouse effect further.

Another concern is that these exploration projects are being carried out by private mining corporations. As noted by Kwame Nkrumah in his book Neocolonialism: The Highest Stage of Imperialism, extraction of raw materials is one way that “foreign capital is used for the exploitation rather than for the development of the less developed parts of the world.”

Mali has experienced this through goldmining — gold accounts for 80 per cent of its total exports, but the profits flow into the pockets of foreign mining companies like the Australian-owned Resolute Mining. It has been estimated that Mali loses over $500 million annually to illicit financial flows and corporate tax avoidance associated with the gold industry.

If the natural hydrogen industry takes off and Hydroma is able to export hydrogen gas as an energy vector, will Malians see the benefits of this? Or will the electrification of Bourakebougou village remain a novel case study, a mere prelude to the exploitation of these reserves in richer countries?

The situation in South Australia is not unrelated. No treaty has ever existed between the settler-colonial state of Australia and its indigenous people, despite repeated and multiple calls from aboriginal people.

The exploration licences granted by the South Australian government encompass the traditional sovereign lands of the Barngarla and Narungga people. If natural hydrogen is discovered, will they be consulted as to whether their lands can be used for extraction?

In a country that directly gave consent to the mining company Rio Tinto to destroy a 46,000-year-old sacred aboriginal site in the Juukan Gorge belonging to the Puutu Kunti Kurrama and Pinikura people, a course of action that prioritises the needs and wishes of aboriginal people seems unlikely.

It is possible that hydrogen gas could be the clean, renewable energy source that finally helps the world break away from its reliance on fossil fuels. Whether renewable mining is possible is unclear. But aside from whether replenishing hydrogen reserves are sufficiently abundant, the signs of their extraction heralding a just, equitable, green world are currently scarce.