February 4, 2025

Impact Deep Dive: Feeding the World with Sustainable Ammonia

Ammonia is a critical component of global food security, fertilizing fields that feed billions. However, its production is also one of the most carbon-intensive industrial processes. This places ammonia at the heart of two pressing global challenges: ensuring food security while addressing the climate crisis. In this deep dive, we explore the technologies we hope will resolve this tension and transform our food system.

Why ammonia matters: Balancing food security and climate goals

In 1908, German scientist Fritz Haber filed a patent for a novel way to synthesise ammonia, a chemical compound made up of 3 parts hydrogen and one part nitrogen. Nitrogen is plant food, allowing crops to grow faster and bigger. Ammonia is a fantastic delivery system for this plant food, being highly reactive, safe to transport, and cheap with Fritz Haber’s method which was later scaled up by Carl Bosch, giving it a name the “Haber-Bosch” process. The results of Haber-Bosch ammonia production were rapid and mindblowing: just over a century later, Haber-Bosch ammonia is responsible for feeding more than half the world’s population. 

However, that great progress brought great cost. Haber-Bosch production requires extreme conditions, with heats as high as 550°C at a pressure up to 300x what you feel normally on earth. For this, it relies heavily on fossil fuels, emitting 2.3 tons of CO₂ for every ton of ammonia produced—far exceeding the carbon intensity of steel or cement. At almost 200 million tonnes produced globally,  Haber-Bosch ammonia is responsible for up to 1.4% of global CO₂ emissions

Figure 1: Comparison of CO₂ emissions per ton of product (IEA).

Figure 2: Expected ammonia demand up to 2050 for the 1.5°C scenario (IRENA)

As the world’s population grows, so does the demand for ammonia to feed it. And beyond its use in agriculture, ammonia is increasingly being explored as a hydrogen carrier and fuel. All in all, demand is expected to triple by 2050, stepping up the pressure on our net zero goals. 

This dual role of ammonia—as both a lifegiver and a major polluter—demands urgent innovation. So what technologies might take on the Haber-Bosch behemoth?

Rethinking ammonia: Disruptive technologies driving the change

The good news is there are several emerging approaches offering potential for a cleaner path to food. Let’s break them down…

Green Haber-Bosch

The Green Haber-Bosch approach seeks to decarbonize traditional Haber-Bosch synthesis by integrating renewable hydrogen sources and optimizing energy use. By replacing fossil-fuel-derived hydrogen with green hydrogen produced with renewable energy, this method cuts a large portion of emissions. Leaders in these efforts include Topsoe and Yara Clean Ammonia, which are piloting large-scale green ammonia projects.

One key advantage of Green Haber-Bosch is its compatibility with existing Haber-Bosch infrastructure, allowing faster adoption and scaling to meet the global demand. However, challenges remain: the process still requires extreme conditions which demand significant energy. Moreover, even at the projected cost reductions for green hydrogen, the price of green ammonia is likely to remain 2–3 times higher than conventional Haber-Bosch ammonia.

Electrochemical 

Electrochemical production synthesizes ammonia directly from natural airborne nitrogen and hydrogen sources (typically water), powered by electricity. If powered by renewable solar or wind, the method can cut the carbon footprint of production by more than 90%. 

Additionally, with relatively low energy requirements, electrochemical approaches can theoretically produce ammonia in systems smaller than a shipping container. By comparison, Haber-Bosch and its extreme energy needs demand much larger, centralised production facilities. This means electrochemical approaches could enable decentralized green ammonia production, putting a shipping container sized factory directly on farms where the product is needed and cutting both transport costs and emissions.

Despite the promise, electrochemical approaches are still in their infancy and will require substantial investment to scale up and reach viable price points. And while likely to be cost competitive at scale, it’s unlikely they will ever substantially outcompete Haber-Bosch on pure price economics due to how efficient Haber-Bosch is.

Nonetheless, we’re enthusiastic about startups in this space. Early movers like Nitricity and Jupiter Ionic have pioneered ammonia synthesis from airborne nitrogen and waterborne hydrogen, using a relatively more proven process called direct nitrogen reduction as they try to get costs down. Meanwhile, emerging electrochemical approaches that potentially improve on their benchmark include lithium-mediated approaches pioneered by companies including Nitrovolt, and plasma-assisted approaches, led by companies like PlasmaLeap and Vital Fluid

Editor’s note: We’ve skimmed over the technical details here, but if you’re interested to learn more about electrochemical approaches we highly recommend this video.

Biocatalysis

Biocatalysis employs microbes or enzymes to produce plant-available nitrogen, inspired by natural processes. Where other methods produce ammonia in a factory to apply to soil, biocatalysis puts the factory (the microbe) into the soil. In addition to making plant-available nitrogen over the long term, these living factories can have major co-benefits like healthier microbiome, greater soil stability and increased soil carbon. 

Figure 3: Natural nitrogen cycle and nitrogen-fixing microbes.

The challenge lies in biology being sensitive to environmental conditions, meaning one solution rarely fits all. Furthermore,  the highest yield microbes known today can only produce around 25% of the nitrogen typically applied to fields via synthetic ammonia – so it can’t completely replace ammonia for most conventional farmers at this stage.   

The space has seen some notable companies make waves including Pivot Bio and Kula Bio, which develop nitrogen-fixing microbes to reduce the need for synthetic fertilizers. Given the huge market and high variety of crop types, soil types and farmer practices, we expect many more companies to emerge and we’re bullish on biological solutions being an essential ingredient in displacing Haber-Bosch.

Photocatalysis

Photocatalysis of ammonia refers to the process of using light to synthesize ammonia. It leverages photocatalysts – materials that absorb light and generate chemical reactions – to synthesise ammonia  under mild conditions. Leading innovators in this space include Syzygy Plasmonics, which is developing solar-driven chemical reactors.

Needing only sunlight, water and air, this approach is both the coolest sounding ammonia production technologies (subjectivity noted), and potentially one of the cleanest. However, photocatalysis research is much earlier than any other approach, requiring significant R&D investment to prove that it works even at a tiny scale, let alone at large scale. Our view is it’s too early to get excited about just yet, but it could be a real dark horse in the race. 

Concluding thoughts: If you can’t take down Haber-Bosch, find a way around

The path to taking down the Haber-Bosch giant looks daunting. Scale remains the biggest hurdle, as conventional Haber-Bosch’s established infrastructure and efficiency have resulted in rock bottom costs. Without an increase in the price of fossil fuels or strong regulatory frameworks—such as carbon pricing or subsidies—attempts to green up Haber-Bosch will likely never gain a meaningful foothold. Meanwhile, electrochemical and photocatalytic pathways need huge research and scale up investment to close the cost gap. And while promising, biocatalysis doesn’t look to be able to produce enough volume to completely replace synthetic ammonia. 

And yet, we’re optimistic about the opportunities and explicitly those that don’t compete head on with Haber-Bosch on its home territory – particularly electrochemical and biocatalytic approaches.Decentralized production models with electrochemical synthesis could simultaneously compete on the price of “delivered nitrogen” and provide security for regions without access to large-scale Haber-Bosch infrastructure. Meanwhile, biocatalysis not only cuts ammonia needs, but also improves overall soil health with long term benefits. 

We’re looking to invest into solutions like these that find a way around Haber-Bosch, which we believe will revolutionize the fertilizer industry. 

Enjoyed this deep dive? Subscribe to Rubio’s newsletter for more insights into transformative technologies shaping a sustainable future.