Lightning-Like Plasma To Make Green Ammonia Affordable

The Path To A Green Ammonia Economy

Ammonia, or NH₃, has been considered a great potential candidate to replace liquid fuel made from oil and other fossil fuels. This is because it is made using an extremely abundant resource, atmospheric nitrogen (N₂), and does not necessarily need oil or methane for its production.

As ammonia is an important fertilizer, its production is currently a massive part of the chemical industry, making it the second most highly produced chemical in the world.

Ammonia is currently mostly produced through the Haber-Bosch process, combining nitrogen to hydrogen to produce ammonia, using high pressure and high temperatures, making it inherently energy intensive.

Source: Angewandte Chemie

However, the source of this hydrogen affects how polluting ammonia production can be. Today, most of the hydrogen for ammonia production is sourced from fossil fuels, making ammonia responsible for 1.3% of global carbon emissions.

Ideally, an ammonia economy would rely on so-called green ammonia generated from renewable energy. This distinguishes it from other types of ammonia:

• Grey/brown ammonia: produced from fossil fuels.
• Blue ammonia: produced from fossil fuels but with carbon capture.
• Pink ammonia (sometimes also called yellow ammonia): produced from nuclear energy.
• Turquoise ammonia: produced from the pyrolysis of methane. This breaks down methane into hydrogen and solid carbon, with the hydrogen later converted to ammonia. The solid carbon can be stored or used for applications like carbon fibers.

As long as ammonia is not mostly green ammonia, using it to replace fossil fuel in transportation and industries is rather pointless, as it just changes the point where fossil fuels are consumed.

“Industry’s appetite for ammonia is only growing. For the past decade, the global scientific community, including our lab, wants to uncover a more sustainable way to produce ammonia that doesn’t rely on fossil fuels.

Pr. PJ Cullen – Professor at the University of Sydney and the Net Zero Institute

This is why new discoveries completely changing how ammonia is produced, away from the century-old Haber-Bosch process, could be a game changer.

Such an innovation might just have been made by researchers at the University of Sydney (Australia) and Zhejiang University (China), using plasma to produce nitrogen from air. They published their results in Angewandte Chemie¹ under the title “Regulating Multifunctional Oxygen Vacancies for Plasma-Driven Air-to-Ammonia Conversion”.

Why Ammonia?

If ammonia is essentially transformed hydrogen, why not use hydrogen directly?

The difference with hydrogen is that ammonia is a much larger molecule than H₂ and much more stable. This makes its transportation and storage a lot easier. Ammonia is also almost 50% more energy-dense than liquid hydrogen.

Source: Kleinman Center For Energy Policy

This energy density and easier storage makes ammonia a prime candidate for use in transportation, especially energy-hungry long-distance travel like shipping, something we discussed in detail in “Decarbonizing Global Shipping Lanes Through Green Ammonia”.

It would also make ammonia a good candidate for year or month-long storage, a long-standing issue for balancing energy grids reliant on green energies, with, for example, the surplus of solar energy in summer or during high-wind weeks used to produce surplus ammonia that would be consumed during winter or low-wind seasons.

Issues With Ammonia Production

As long as ammonia production relies on Haber-Bosch, this switch to a greener fuel might take time.

The main reason is that green hydrogen production is complex and expensive, often requiring rare metals like platinum, although this is likely to change thanks to progress in nanotechnology, like using nanorods of nickel instead.

The other reason is that producing ammonia with hydrogen means it is a multi-step process, with each step requiring capital investment and reducing the total energy yield of the entire production process:

• Green energy must first be produced with solar, wind, or hydro technologies.
• That electricity is then transported to an electrolyzer producing hydrogen.
• The hydrogen is then used for ammonia production.

As green energy is generally more intermittent and decentralized, this creates additional costs to require centralized hydrogen and ammonia production.

“Currently, generating ammonia requires centralized production and long-distance transportation of the product. We need a low-cost, decentralized and scalable ‘green ammonia”

Pr. PJ Cullen – Professor at the University of Sydney and the Net Zero Institute

How Nonthermal Plasma Could Revolutionize Green Ammonia

What Is Nonthermal Plasma?

Other methods than Haber-Bosch exist to produce ammonia. The general idea is to use electricity to oxidize nitrogen, and then add hydrogen atoms (nitrogen reduction reaction – eNRR).

However, these methods are limited by nitrogen low solubility, and unwanted other reactions in solutions containing water. This is why Nonthermal plasma (NTP) is considered instead, as NTP is more suited for oxidation reactions than chemical reduction.

Source: Angewandte Chemie

The resulting nitrate (NO₃⁻) and nitrite (NO₂⁻) have a solubility in water nearly 40,000x that of N₂.

These methods are promising, but require nitrogen and oxygen to be extracted from air and purified, increasing costs.

This is why approaches where air is directly activated to produce NOx and the resultant NOx intermediaries reduced into NH₄⁺ via electrochemical conversion are attractive.

Copper-Iron Catalyst

The researchers used a nanogrid of copper (P-Cu), in which an oxygen plasma atmosphere was used to create defects(CuxO/Cu) and highly reactive species such as O⁻ ions, O atoms, and O₃ (ozone) molecules. These reactive oxygen species interact with Cu, leading to surface oxidation.

Then the addition of iron atoms created stable Fe–O–Cu bridge bonds on the surface.

Source: Angewandte Chemie

Using energy-dispersive X-ray spectroscopy (EDS), the researchers could study the highly complex crystal structures formed by this process. The very small rods and complex structures increased the surface of the material, making it a better catalyst.

Source: Angewandte Chemie

Electrocatalysis Of Ammonia

Fe₂O₃ NPs/Cu was used as a cathode for the production of ammonia from nitrogen and water, directly controlling both the oxidation of nitrogen and the electrolysis of water into hydrogen.

Tests proved that the introduction of Fe₂O₃ on copper effectively enhances electrocatalytic activity.

Source: Angewandte Chemie

They analyzed in detail how the ammonia production works, and confirmed it is actually a complex, multi-layered chemical reaction occurring very quickly, with NO₂ turning into NH₃.

Source: Angewandte Chemie

More importantly, the reaction had an almost 100% faradaic efficiency at 300 mA, meaning that most of the electricity used is converted into chemical energy, making it an order of magnitude more efficient than the multiple steps of classical water electrolysis (for hydrogen production) and then nitrogen-to-ammonia conversion.

“This new approach is a two-step process, namely combining plasma and electrolysis. We have already made the plasma component viable in terms of energy efficiency and scalability.”

Pr. PJ Cullen – Professor at the University of Sydney and the Net Zero Institute

Moving Forward

Overall, this method demonstrates that there are other paths toward ammonia production that might entirely bypass the Haber-Bosch process, and the need to separately produce green hydrogen in the first place.

This also represents an improvement compared to a previous version of this technology, which had to use a copper-palladium catalyst instead of iron, with palladium an expensive metal.

This study was mostly focused on the development of an efficient catalyst for the oxidation of nitrogen directly from unfiltered and refined air.

To make it economically viable, the electrolyser component producing the hydrogen will still need to be improved. Luckily, progress in hydrogen production using non-previously used catalysts or even self-optimizing catalysts is being made.

So most likely, in the medium term, we will see the combination of different technologies into a commercial ammonia production machine, like direct nitrogen oxidation with plasma using copper & iron, and water electrolysis using equally cheap metals.

These units could be installed directly on sites of energy production of green energy, and the resulting ammonia production stored in a relatively cheap tank (compared to hydrogen), to be shipped away by pipeline, trucks, or tankers.

It will most likely be companies able to vertically integrate green energy generation, ammonia production, and shipping of the ammonia that will benefit the most from such designs.

Ammonia Company

Aker Horizons ASA (AKH.OL)

Aker Horizon is a subsidiary of the Aker group centered around green energy. The group is a large Norwegian conglomerate with a focus on renewables and marine/offshore businesses.

Source: Aker

Aker Horizon is the holding company for several subsidiaries, including green hydrogen, onshore and & offshore wind farms, and solar farms. This includes Mainstream Renewable Power, an utility company with 20.4GW of renewable energy in development in South Africa (12.3GW) and other countries (Asia, South America, Europe).

The company is notably very active in hydrogen and green ammonia generation, with a goal to decarbonize Arctic shipping, as well as interest from data centers.

Source: Aker

Aker is not a purely green ammonia company but can handle the entire vertical integration of green ammonia, from offshore windmills to hydrogen generation (for now) to green ammonia production. It is also working on projects like waste-to-energy in France, a biomass plant in Germany, and carbon capture in the Middle East (Saudi Arabia and the UAE).

In May 2025, Aker has been looking at some restructuring due to low prices in the green energy sector, essentially looking to fully reacquire its carbon capture operations, and the reintegration of AKH Holding (Mainstream Renewable Power, and the Narvik green ammonia projects) into Aker Horizon after a separate listing of some of its shares.

Source: Aker

This makes it a good stock for investors looking for long-term exposure to the green energy sector at large, with a strong positioning on green ammonia, but also other green energies, and some geographical diversification away from North American stocks.

Study Referenced

^{1. Wanping Xu, Jiaqian Wang, Tianqi Zhang, Jungmi Hong, Qiang Song, Zhongkang Han, Patrick Cullen. (2025) Regulating Multifunctional Oxygen Vacancies for Plasma-Driven Air-to-Ammonia Conversion. Angewandte Chemie. 22 April 2025 https://doi.org/10.1002/anie.202508240}