Supply and demand: seeking fertilizer sustainability

The fertilizer sector faces a significant challenge; how to supply the world’s growing agricultural needs in a manner that does not significantly impact the environment. Carbon footprints, tailings, and water pollution are just a few of the problems that need to be addressed in order to produce in a sustainable manner.

Nitrogen

Without a doubt, the amount of carbon dioxide released by the fertilizer industry throughout its production and consumption chain is the most pressing issue. Estimates place total greenhouse gas (GHG) emissions from manufacturing plants, transportation, and farms at approximately 2.6 billion tpy.

Governments around the world have enacted legislation and directives to reduce emissions. The EU’s Renewable Energy Directive (RED III), requires the fertilizer industry to replace 42% of grey hydrogen with Renewable Fuel of Non-Biological Origin (RFNBO) by 2030. Canada has imposed net zero goals by 2050 on wide swathes of their economies; Ottawa has been pondering ways to reduce agricultural emissions by 30% through a combination of tilling methods and fertilizer restrictions.

Nitrogen fertilizer production plants account for about 450 million t of GHG emissions. In order to make ammonia, large quantities of energy are needed to capture and purify nitrogen and hydrogen, then combine them into a stable chemical. Over the last decade, producers and equipment suppliers have made significant improvements in processes (such as fancy new catalysts), in order to save energy. In 2018, Nutrien, one of the world’s largest fertilizer companies, set a goal to reduce its operational GHG emissions from 670 kg/t to 470 kg/t by 2030. In 2024, it reported it was halfway to its goal, at 570 kg.

But the constraints of the traditional Haber-Bosch process means that most of the low-hanging fruit has already been harvested; further reductions will require ever-greater investments for diminishing returns. Entirely new ways of producing ammonia will have to be designed and implemented.

Carbon capture and sequestration (CCS), can meaningfully reduce emissions. In April 2025, CF Industries joined forces with Japanese energy company JERA to build a 1.4 million tpy blue ammonia plant in Louisiana, US. When the US$4 billion project comes on-stream in 2029, it will capture and sequester 2.4 million tpy of CO₂, the equivalent of removing half a million cars off the road.

As for the production method itself, research and investment is focusing on several fronts. The first is to use wind and solar-generated power to produce hydrogen through electrolysis. Most hydrogen is traditionally produced by splitting natural gas into hydrogen and carbon elements and then isolating the former. The process generates over 10 kg of CO₂ for every 1 kg of hydrogen. Electrolysis produces hydrogen by separating it from water molecules, releasing only oxygen as a by-product.

Finally, the Haber-Bosch process itself can be powered by renewable power. Reactors combine hydrogen and nitrogen under immense pressure and temperature conditions; if natural gas is used to generate the power, it adds about 500 g of CO₂ emissions for every 1 kg of ammonia produced. By swapping in renewables as power sources, those GHG emissions are eliminated. In all, green ammonia purges several hundred kilograms of GHGs per tonne from the production process.

There are caveats. First, the sun does not always shine and the wind does not always blow. Over the last century, ammonia plants have been refined to optimise outputs based upon reliable power sources. Intermittent power reduces efficiency and can even harm equipment. Much research is needed to build in robustness and smooth out fluctuations inherent in renewable energy.

Secondly, the cost of electrolysis needs to come down. While great strides have been made in reducing the costs of wind mills and solar panels, electrodes remain stubbornly expensive, and breakthroughs in electrolysis technology are not expected to provide significant relief through the next decade.

Third, re-engineering the entire manufacturing process for the world’s second-most produced chemical will be extremely expensive as well as daunting. Vast resources will be needed to bring countless components from the lab bench to economic scale.

A case in point is Chemical Looping Ammonia Production (CLAP), a promising method that lowers both pressure and temperature requirements in reactors. CLAP has the potential to replace or integrate with Haber-Bosch, providing a less energy-intensive, cost-effective alternative for ammonia production. It works by creating a bulk metal nitride-carrying material and then reacting it with hydrogen to create ammonia. The carrier materials are then endlessly recycled. Currently, the CLAP process remains in the lab and has yet to be tested at commercial scale, but offers significant potential for the next decade.

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Read the article online at: https://www.worldfertilizer.com/special-reports/22012026/supply-and-demand-seeking-fertilizer-sustainability/