The search for abundant sustainable energy has brought an unexpected resource to light: geological hydrogen, also known as natural or white hydrogen. This naturally occurring hydrogen, trapped in the Earth's crust, is gaining attention as a potential enabler for clean energy. Unlike hydrogen produced from fossil fuels, geological hydrogen is created through natural processes and offers a simpler and potentially more cost-effective path to decarbonization.
Hydrogen plays a crucial role in various industries and applications. According to the European Hydrogen Observatory, refineries and the ammonia industry account for 82% of total hydrogen demand in the EU, EFTA, and the UK, with refineries using 57% (~4.5 Mt) and ammonia 25% (~2 Mt) of the total hydrogen demand.1 Beyond these major uses, hydrogen is also employed in steel manufacturing, transportation (particularly for heavy-duty vehicles, ships, and potentially aviation), energy storage and grid balancing, industrial heat generation, and synthetic fuel production. As the world seeks cleaner energy solutions, geological hydrogen could play a crucial role in meeting these diverse industrial needs while reducing carbon emissions.
A natural wonder
Compared to green hydrogen, which is produced by electrolysis using renewable energy, or blue hydrogen, which is produced from natural gas with carbon capture, geological hydrogen offers the advantage of direct extraction.2 The U.S. Geological Survey (USGS) believes that continental cratons and deep sedimentary basins could hold vast reserves of hydrogen that could accelerate global decarbonization goals.3
This naturally occurring hydrogen is formed through various geological processes: Serpentinization, a common process in the Earth's mantle, occurs when water infiltrates ultramafic rocks rich in iron and magnesium, triggering a chemical reaction that produces hydrogen. This continuous source of hydrogen can seep into shallower crustal layers.
Another process, radiolysis, involves the splitting of water molecules into hydrogen and oxygen due to natural radioactive decay. Minerals containing uranium, thorium, or potassium emit radiation that interacts with groundwater, generating hydrogen over geological timescales.
Lastly, thermolysis, which occurs in tectonically active regions under extreme temperatures, causes water molecules to dissociate into hydrogen and oxygen, further contributing to the natural generation of geologic hydrogen.
These processes yield hydrogen in concentrations that could potentially be tapped as a renewable and carbon-free energy source. The Earth's reserves of geologic hydrogen are potentially immense, sparking interest in academic and industrial sectors as a promising resource for sustainable energy production and diverse applications across industries.
Figure 1: Earth’s natural hydrogen factories.4
Rock to rocket fuel
While the presence of geologic hydrogen is promising, extracting it efficiently presents significant challenges. Researchers are exploring various methods to bring this fuel to the surface:
Drilling and Capture: Similar to natural gas extraction, but with specialized equipment to handle hydrogen's unique properties.
Enhanced Natural Production: Stimulating hydrogen-producing reactions in the subsurface to increase yield.
Geologic Carbon Sequestration: Combining hydrogen extraction with carbon storage to create a dual-purpose operation. This concept remains in its early stages, with significant technical and logistical challenges to address. Current efforts in carbon sequestration typically focus on CO₂ storage rather than coupling it with hydrogen extraction.
One innovative approach being developed at MIT aims to extract hydrogen from rocks using electrolysis. This method could potentially unlock vast reserves of clean energy while simultaneously addressing challenges in renewable energy storage.5
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The hydrogen economy
The potential market for geological hydrogen is immense. According to a report by Deloitte, the hydrogen market is expected to surpass the value of the liquid natural gas trade by 2030 and grow to US$1.4 trillion per year by 2050.
Governments worldwide are investing resources in hydrogen development, with the US Department of Energy's ARPA-E program actively supporting research into geological hydrogen. Countries with favorable geological conditions are also positioning themselves as future natural hydrogen leaders.
Investors are taking note, with companies striving to develop efficient extraction technologies and capitalize on the emerging natural hydrogen boom. Although research is still in its infancy, the potential gains are considerable, especially as hydrogen is becoming increasingly important as a key component of the global energy transition.
Developmental challenges
Despite its potential, geologic hydrogen development faces several challenges. The current state of hydrogen extraction technology is still nascent, requiring innovations to safely and economically capture and store hydrogen without significant energy loss. Economic feasibility is another hurdle; geologic hydrogen must become more cost-effective to compete with established hydrogen production methods, and scalability remains a major concern. Additionally, while geologic hydrogen is a clean energy source, the environmental impact of drilling and extraction must be carefully managed to prevent issues like groundwater contamination or habitat disruption. The regulatory landscape is also underdeveloped, and comprehensive frameworks will be essential to ensure safe and environmentally responsible practices as the industry evolves.
Discovery to deployment
The potential of geologic hydrogen is immense, but significant effort is needed to transition from discovery to widespread adoption. Achieving this will require intensified research, strategic investments, and robust infrastructure development. Collaboration among universities, energy firms, and government agencies will play a pivotal role in advancing the necessary technologies. As extraction methods evolve, geologic hydrogen could seamlessly integrate into existing renewable energy strategies, enhancing grid stability by serving as a dependable backup for variable energy sources.
Nonetheless, the path from concept to commercial viability demands sustained innovation, coordinated efforts, and commitment across multiple sectors.