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Green Chemistry

Addis Energy aims to decarbonize ammonia production

Boston-based start-up goes underground to clean up chemistry’s most emission-heavy process

by Vanessa Zainzinger, special to C&EN
February 4, 2025

 

Four people pose in a laboratory.
Credit: Business Wire
Addis Energy’s founding members in the firm’s Boston-area labs

Ammonia production via the Haber-Bosch process is the chemical industry’s greatest source of greenhouse gas emissions and accounts for 2% of global energy consumption. Now, a Boston-based start-up says it can make ammonia cleanly, cheaply, and quickly by injecting nitrate-containing water into iron-rich rock and letting the Earth do the rest.

Addis Energy, which launched in April but revealed its technology just last month, has raised $8.75 million to date from the US Department of Energy’s Advanced Research Projects Agency-Energy and the venture capital firms Engine Ventures, Pillar VC, and Voyager Ventures.

The start-up’s process, which has been demonstrated in the lab but not yet in a natural setting, was devised by Massachusetts Institute of Technology professors of materials science and engineering Iwnetim Abate and Ju Li, postdoc Yifan Gao, and five other individuals at MIT.

When the process is practiced in the field, water will be mixed with a source of nitrogen and particles of a metal catalyst and then injected into iron-rich subsurface rock. The water will react with the iron to generate hydrogen, which can immediately bond with the nitrogen atoms also carried in the water.

The deep underground environment provides the high temperatures and pressures required by the Haber-Bosch process—the Earth itself becomes a geochemical reactor. A second well near the injection well then pulls the ammonia solution out of the rock and into tanks on the surface.

Even though it is a geological process, the reaction takes only a few hours, says Addis CEO and cofounder Michael Alexander. Moreover, the process is net energy-positive and requires no fossil fuels.

“If you replaced all the US ammonia production with this process, you’d save 500 billion cubic feet of natural gas consumption a year,” or 14 billion m3, he says. Before cofounding Addis, Alexander worked as a chemical engineer in the oil and gas industry.

Compared with other routes for producing low-carbon ammonia, which typically require 16 GJ of net energy and cost $1,150 per metric ton (t), Addis’s geologic ammonia process generates 18 GJ/t of net energy and will cost, according to the firm’s projections, $200–$500 per metric ton to run.

“Traditionally, we’ve had to choose between either low-cost energy or clean energy, and one of our goals is to break that dichotomy and have clean resources that are also cheap,” Alexander says.

But first, Addis has to make its technology work at scale. The team of four is running core flood tests, which allows them to replicate subsurface pressure conditions in the lab with rocks from the field. In parallel, its in-house geologist and geochemist are identifying potential pilot program locations across the US and gearing up to take testing out of the lab by this time next year, Alexander says.

The iron-rich rock that Addis needs for its process is prevalent enough, Alexander says. Called mafic or ultramafic rock, this rock is of great interest to geochemists for its ability to react with carbon dioxide and store the greenhouse gas underground. “It’s the combination of magnesium, which helps with CO2 mineralization, plus ferric or ferrous iron, which is what we’re looking to oxidize to drive our reaction,” he says.

Abate’s research initially focused on geologic hydrogen, which occurs naturally underground through chemical reactions between water and these types of rocks. But the tiny molecule is much harder to capture and transport than ammonia.

Still, the technology has generated excitement among geologic hydrogen researchers. Many labs around the country are looking into similar chemical reactions for producing hydrogen, says Allegra Hosford Scheirer, a consultant for the geologic hydrogen consultancy Geomodeling Solutions and an adjunct professor at Stanford University.

“Overall, it’s tremendously exciting,” she says. “The biggest takeaways for me are that the reaction produces no greenhouse gas emissions [and] that it looks like it’s going to be very inexpensive.”

The crunch point, Hosford Scheirer says, will be whether the technology can work just as well in the field. “This is still a benchtop experiment done very, very systematically and carefully. If this can be scaled, then the technology could achieve a huge amount of geologic ammonia.

“I know many scientists working on simulated hydrogen in the lab facing the same issue: sure, you can produce some grams of it in the lab, but what happens when you start trying to do it in the Earth?”

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