Agricultural and industrial production depends heavily on ammonia today but making this chemical is energy intensive and produces harmful greenhouse gases. A research team at MIT has proposed an innovative approach that could dramatically shift this paradigm: Researchers have found a better approach in ammonia production by letting the Earth serve as its own geothermal reaction system for safe production of ammonia underground. The processes uses Earth’s naturally occurring heat and pressure, provided free of charge and free of emissions, as well as the reactivity of minerals already present in the ground.
The Haber-Bosch process produces nitrogen-based fertilisers such as Ammonium Nitrate, that feed our global population in conventional methods. The production method uses excessive heat and pressure driven by fossil fuels and creates significant environmental damage. The method produces most of Earth’s CO₂ emissions worldwide.
Professor Iwnetim Abate and Ju Li at MIT headed a team that showed how underground thermal energy could transform rocks naturally into ammonia. The method feeds water with nitrogen and catalytic metal powders into iron-bearing rocks through one of two wells to produce hydrogen from water which merges with nitrogen to make ammonia. Researchers pump the newly produced ammonia up from the ground through a second well.
A New Method of Ammonia Synthesis
The system produces ammonia without fossil fuels because it uses natural geothermal energy sources. The old manufacturing techniques heavily depend on methane to produce hydrogen yet they release carbon dioxide waste. MIT’s process produces hydrogen below ground upfront to remove carbon emissions from the final product distribution process.
The team’s experiments have so far been conducted in the lab, with plans to test the method at an actual geological site within the next two years.
“We call this ‘geological ammonia,’” says Professor Abate, highlighting the integration of Earth’s natural processes into industrial chemistry. “The Earth becomes the factory.”
Graduate Student Yifan Gao from MIT stated:
“When I first produced ammonia from rock in the lab, I was so excited,” “I realised this represented an entirely new and never-reported approach to ammonia synthesis.’”
The research paper’s co-authors are MIT professors of materials science and engineering Iwnetim Abate and Ju Li, graduate student Yifan Gao, and five others at MIT.
This method brings benefits that go beyond making ammonia production carbon-free. The innovation has the power to decrease worldwide CO₂ emissions by 1% helping solve major climate problems. By using nitrogen-rich wastewater treatment byproduct the team can achieve better water purity and better nitrogen resource management simultaneously.
The only extra ingredient needed to complete the process was the addition of a source of nitrogen, such as nitrate or nitrogen gas, into the water-catalyst mixture being injected into the ground. Then, as the hydrogen gets released from water molecules after interacting with the iron-rich rocks, it can immediately bond with the nitrogen atoms also carried in the water, with the deep underground environment providing the high temperatures and pressures required by the Haber-Bosch process.
“We call this geological ammonia,” Abate says, “because we are using subsurface temperature, pressure, chemistry, and geologically existing rocks to produce ammonia directly.”
Whereas transporting hydrogen requires expensive equipment to cool and liquefy it, and virtually no existing infrastructure that can be easily implemented exists for its transport (except near oil refinery sites), transporting ammonia is easier and cheaper and something that has been done over many years. It’s about one-sixth the cost of transporting hydrogen, and there are already more than 5,000 miles of ammonia pipelines and 10,000 terminals in place in the U.S. alone.
Moreover, Abate explains, ammonia, unlike hydrogen, already has a substantial commercial market in place, with production volume projected to atleast double by 2050, as it is used not only for fertiliser but also as feedstock for a wide variety of chemical processes such as ammonium nitrate production.
Geoffrey Ellis, a geologist at the U.S. Geological Survey, praised the concept as “transformative” while emphasizing the need for validation at commercial scales. The research has also garnered support from MIT’s Climate Grand Challenges program, which aims to accelerate breakthroughs in sustainable technologies.
The new method shows promise to transform both ammonia production and the entire chemical industry. Through their experiments MIT researchers reveal how rethinking Earth’s natural systems creates clean efficient ways to solve modern problems. The research team hopes to build a new model that helps unite natural processes with industrial operations toward sustainable ends.
As the team works further toward optimisation people worldwide expect them to create better and greener ways to produce vital chemicals for human advancement.
