Assessing viability, environmental impact, and technological challenges. Image credit: Ashim D’Silva, via Unsplash.
Using hydrogen as an energy source has been imagined as a potential solution to our fossil-fuel problems for over 150 years. A 2020 Forbes article announced hydrogen as “the ‘green’ fuel of the future”. George W. Bush advocated for hydrogen-powered vehicles in 2003. But the idea goes back even further to Jules Verne, who imagined hydrogen as an alternative fuel in 1875.
Recently, interest in hydrogen power has surged again, fuelled by the climate crisis, with the US Department of Energy granting $20 million for research into using geologic hydrogen as a green fuel. Geologic hydrogen consists of continuously-produced, naturally-occurring subsurface hydrogen deposits, formed by reactions between rock in the Earth’s subsurface and water.
Using hydrogen as an energy source has been imagined as a potential solution to our fossil-fuel problems for over 150 years.
The funding has gone towards a project run by ARPA-E, a US government agency tasked with advancing energy technologies, seeking to accelerate geologic hydrogen production and better utilise its reservoirs for extraction. This supposedly aligns with the Biden Administration’s net-zero carbon goals, while also enhancing the US energy economy.
Exploration of the fuel has also occurred globally. The Netherlands was home to a 2019 project that heated an apartment complex of 25 homes with 100% hydrogen, soon to be extended to 550 other homes in the country. Dozens of start-ups based around hydrogen power have been founded in Australia. One US start-up, Koloma, has raised $90 million to explore geologic hydrogen, largely funded and supported by Bill Gates.
But why now this sudden peak in interest?
In 2012, a decades-old borehole in Mali was found to be continuously leaking 98% hydrogen gas. The discovery was confirmed by Aliou Diallo, a wealthy Malian businessman, who later published a 2018 paper in the International Journal of Hydrogen Energy on the possibility of hydrogen deposits in the Earth. This re-sparked the age-old debate over the potential of hydrogen fuel. In 2022, Geoffery Ellis at the US Geological Survey estimated that 2.5 billion tonnes of stable deposits of hydrogen exist within the Earth, indicating ‘vast overlooked stores of hydrogen gas’.
However, the US government plans to generate even more geologic hydrogen by accelerating its formation. For instance, a high-temperature reaction called serpentinisation occurs between water and iron-rich minerals, such as olivine in the Earth’s mantle, oxidising the iron and releasing hydrogen. Pumping more water underground could produce more hydrogen—dubbed “orange” hydrogen (referring to the colour of oxidised iron).
For the US, methods echoing this could allow them to reach their net-zero goals in a hugely profitable manner. They could reshape the global economy into a new cleaner “hydrogen economy”, moving away from an old-fashioned oil market, while also encouraging the policy of homeland economics. If they can generate a theoretically unlimited supply of hydrogen fuel, they could easily dominate this new economy.
Perhaps we may even see a new era of petro-aggression, where oil states tend to engage in conflict, and a rise in global tensions between the US and other global powers.
Success of a fuel
The same mass of hydrogen contains three times the amount of energy as conventional petrol, making it very energy efficient. Further, when burned, the fuel releases only water vapour and heat, and thus is a seemingly promising green fuel for our future.
However, in the race to electrify cars, batteries won against hydrogen fuel cells, which combine hydrogen and oxygen to form electricity, due to issues with storage. Hydrogen storage requires either large tanks or high pressures which, until hydrogen can be effectively and safely stored in such ways, would not be realistic or profitable to use widely.
The same mass of hydrogen contains three times the amount of energy as conventional petrol, making it very energy efficient.
Such storage would also need to prevent any leakage. While hydrogen itself is not a greenhouse gas, it can increase the lifespan of greenhouse gases like methane, contributing to an indirect warming effect. More research would be needed to establish the greenhouse gas footprint of geologic hydrogen.
Hydrogen fuels are dangerous?
This perception comes largely from popular history and culture. The 1937 fiery destruction of The Hindenburg, a German airship, became a famous example after it set alight and was destroyed due to the combustion of the hydrogen gas it used for buoyancy. Similarly, many will confuse the science of the first nuclear weapon, coined the hydrogen bomb, with hydrogen fuel sources. The recent film ‘Oppenheimer’ may have reinforced this belief. Other films, such as ‘Knives Out 2’, warn of the dangers of using untested hydrogen fuels to power homes.
In surveys conducted across the UK population, in turn, many felt “ambivalent” about the fuel, with 64% having no basic knowledge of the technology, with only some seeing the fuel as environmentally beneficial. A historical example of this support is the 1970’s Oil Crisis, and the consequent endorsements of hydrogen as an alternative car fuel. However, 34% of those surveyed see hydrogen as dangerous, believing it to be highly flammable and explosive despite it being safer than most commonly used fuels.
For geologic hydrogen to be a future success, we first need to properly understand how it works. Then it will need to become cheaper than current fuels.
In comparison to conventional fuels, a higher percentage of gaseous hydrogen is required in the air for it to be flammable, and higher temperatures are required for it to burn. Recent technologies mean hydrogen should be safe to store and use. However, there are no explicit methods published for the planned production, extraction and distribution of geologic hydrogen, so their safety will have to be further assessed.
Should people’s opinions matter? For geologic hydrogen to be a future success, we first need to properly understand how it works. Then it will need to become cheaper than current fuels, since many will be unable or unwilling to pay higher energy costs. Finally, it will be up to us to embrace the technology and ensure policy makers make the move to what could very well be the green fuel of the future.
