Harnessing Earth’s Heat for Carbon-Free Ammonia Production
MIT researchers developed a CO2-free method to produce ammonia using subsurface heat, rocks and water.

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Researchers have demonstrated a method to produce ammonia using Earth's subsurface heat and pressure, potentially offering a cleaner and energy-efficient alternative to traditional industrial processes. Published in Joule on January 21, the study outlines a process that generates ammonia from nitrogen-laced water and iron-rich rocks without external energy input or carbon dioxide emissions.
Ammonia
A chemical compound (NH₃) widely used as a fertilizer and a potential clean fuel. It is typically produced industrially through the energy-intensive Haber-Bosch process.A geological inspiration for a chemical innovation
The idea emerged from a discovery in Mali, West Africa, during the 1980s, where hydrogen gas was found streaming from a well. Scientists linked the phenomenon to natural chemical reactions between water and rocks beneath Earth’s surface. Inspired by this process, researchers led by Iwnetim Abate at the Massachusetts Institute of Technology (MIT) explored whether similar reactions could be used to produce ammonia sustainably.
“It was an ‘aha’ moment. We may be able to use Earth as a factory, harnessing its heat and pressure to produce valuable chemicals like ammonia in a cleaner manner.”
Dr. Iwnetim Abate.
Ammonia plays a critical role in agriculture as a fertilizer and has potential as a clean fuel. However, conventional ammonia production via the Haber-Bosch process is energy intensive, consuming 2% of global energy and emitting 2.4 tons of carbon dioxide per ton of ammonia. The new method addresses these challenges by using Earth’s natural forces as a “factory” for ammonia synthesis.
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The research team developed a rock-water reaction system to replicate subsurface conditions. By exposing synthetic iron-rich minerals to nitrogen-laced water, they triggered a chemical reaction that oxidized the rock and produced ammonia. Dubbed “geological ammonia,” the process emitted no carbon dioxide and required no external energy input.
To evaluate the method’s real-world applicability, the team substituted the synthetic minerals with olivine, a naturally occurring iron-rich rock. When combined with a copper catalyst and heated to 300°C (572°F), the process generated 1.8 kilograms (4 pounds) of ammonia per ton of olivine over 21 hours. This proof-of-concept highlights the method’s potential scalability and sustainability.
Olivine
A naturally occurring iron- and magnesium-rich silicate mineral commonly found in Earth’s mantle and some igneous rocks.Nitrogen-laced water
Water containing dissolved nitrogen compounds, such as nitrate or ammonium ions, which can participate in chemical reactions.Scaling up and economic considerations
The research team envisions adapting this process globally, leveraging the widespread availability of suitable rocks. Implementing the method would involve drilling into iron-rich formations, injecting nitrogen-laced water and addressing challenges related to rock mechanics and fluid interactions. A pilot-scale test is planned for 2026 through Addis Energy, a company co-founded by Abate.
Economic analysis shows promising results, with the cost of producing geological ammonia estimated at $0.55 per kilogram, comparable to the $0.40–$0.80 range of conventional methods. Integrating this process with wastewater treatment could enhance its economic viability. By converting nitrogen sources in wastewater into ammonia, the method could generate an additional profit of $3.82 per kilogram.
Implications and future directions
The process could significantly reduce the carbon footprint of ammonia production while offering a way to address wastewater pollution. Beyond its practical applications, the study sheds light on the geological production of ammonia, a process that may have played a role in the origins of life on Earth.
“Nitrogen sources are considered as pollution in wastewater, and removing them costs money and energy. But we may be able use the wastewater to produce ammonia. It’s a win-win strategy.”
Dr. Yifan Gao.
Although significant technical challenges remain, this innovative approach holds promise for transforming ammonia production into a more sustainable and economically viable process.
Reference: Gao Y, Lei M, Sravan Kumar B, et al. Geological ammonia: Stimulated NH3 production from rocks. Joule. doi: 10.1016/j.joule.2024.12.006
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