THOKOZANI MAJOZI AND CAROLINE KAITANO: The energy revolution beneath our feet

Hydrogen — the most abundant element in the cosmos — has been hailed as a miracle fuel for more than two centuries. Clean and energy dense it has powered rockets in the Apollo missions and fuelled visions of zero-emissions transport. Flitting in and out of the energy spotlight through the years, it has always promised more than it delivered. Until now. 

Today’s challenges, stemming mainly from climate change and disruptive environmental patterns, have placed the idea of hydrogen as a fuel back at centre stage, this time with serious momentum. Global warming change is no longer a future threat but a current emergency.

Until most of the buzz has centred on green hydrogen, produced through electrolysis using renewable electricity. But it is expensive, water-intensive and infrastructure-heavy. Invariably, these factors limit its viability, especially in the developing world. 

While hydrogen itself is invisible regardless of its colourful classifications, the various types reflect dramatically different production methods and environmental impacts.

Most hydrogen today is “grey”, produced cheaply from fossil fuels through steam methane reforming but releasing significant amounts of CO2. “Blue” hydrogen uses the same fossil fuel sources but incorporates carbon capture and storage to trap emissions, though it still relies on hydrocarbons and raises concerns about methane leaks.

“Turquoise” hydrogen splits methane through thermal pyrolysis, eliminating CO2 emissions and producing valuable solid carbon, yet remains dependent on natural gas. “Purple” hydrogen uses nuclear-powered electrolysis to split water, offering zero-carbon production but facing challenges from high costs, nuclear waste disposal and public opposition.

“Green” hydrogen, considered the gold standard, electrolyses water using renewable energy sources such as solar and wind, making it environmentally sustainable and aligned with net-zero goals. Still, it remains expensive and water-intensive, requiring 9-18 litres of freshwater per kilogram produced and creating challenges in water-scarce regions. This complex landscape sets the stage for geologic or “gold” hydrogen to potentially transform the industry. 

Geologic hydrogen is a natural, low-cost and renewable form of hydrogen produced deep within the Earth’s crust by geochemical reactions. Extracting and producing geologic hydrogen is not science fiction; it is already powering a village in Mali. Elsewhere, an enormous natural reservoir was recently discovered in France, and promising explorations are emerging from SA, Namibia, Brazil, Australia and the US.

What makes geologic hydrogen compelling as a fuel source for Africa is that it offers the continent, and especially SA, a once-in-a-generation opportunity not just to participate in the energy transition, but to lead it. 

Unlike green hydrogen, geologic hydrogen doesn’t require vast water resources or huge investment in electrolysis infrastructure to produce it. It can be explored and extracted using many of the same tools developed by the oil and gas industry, such as seismic imaging, drilling and reservoir modelling. This creates an ideal opportunity for countries with fossil fuel expertise and infrastructure to pivot to a zero-emission, eco-friendly alternative. 

Geologic hydrogen could be produced at a fraction of the cost of green hydrogen. Current estimates put production costs of green hydrogen between $3 and $6 per kilogram (about R55-R110/kg). On the contrary, early assessments suggest that geologic hydrogen could come in as low as $0.5-$1/kg (R10-R18/kg). For Africa, where cost and infrastructure limitations have historically slowed energy development, this changes everything. 

But the real significance of geologic hydrogen goes beyond cost and technology. It offers a chance for Africa to break with the pattern of energy colonialism. Geologic hydrogen could electrify rural areas, power local industries and reduce dependence on costly fuel imports. It could even allow African nations to shift from exporting raw materials to exporting value-added clean fuels. With geologic hydrogen we have a chance to build a clean energy system that is rooted in African resources, African innovation and African leadership.

To seize this opportunity we need more than good geology. We need smart, inclusive policy and targeted investment. Governments must fund geological surveys and exploration pilots, build enabling regulatory environments and offer incentives that derisk private sector involvement. Crucially, these efforts must involve and benefit local communities, thereby ensuring that hydrogen becomes a tool for broad-based development, not just elite enrichment. 

Academia also has a vital role to play. We must train the next generation of African hydrogen geochemists, process engineers and policy experts. Universities and research institutions should be central in building the knowledge base, conducting resource mapping and shaping hydrogen policy. More importantly, regional collaboration will be key. African countries must work together to establish a coherent strategy that aligns clean energy goals with climate justice and economic equity. 

There is urgency here. Global interest in geologic hydrogen is growing fast. If Africa does not move decisively it risks once again becoming a passive supplier to wealthier nations with more capital and technological capacity. However, if we act now and act with clarity, courage and co-ordination we can define a new energy future on African terms. 

Geologic hydrogen won’t shimmer like solar panels or spin like wind turbines. It’s a quiet, hidden resource. But it may be the most transformative energy opportunity Africa has ever seen. Let’s not wait for the world to lead us. Let’s lead the world. 

• Prof Majozi, a chemical engineer, is dean of the faculty of engineering and the built environment at Wits University and president of the Academy of Science of SA. 

Kaitano is a PhD candidate in chemical engineering whose research explores sustainable hydrogen production, optimisation of water-energy systems and the role of clean energy innovation in Africa’s development.