New ammonia technology offers exciting decarbonisation opportunity

Rhizo PTX, a UK technology start-up, has developed a modular electrolysis stack that can manufacture clean ammonia from just water, air and renewable energy. The effectiveness of the technology has been proven with continuous measurements by an advanced ammonia analyser from Signal Group.

Background

Ammonia has traditionally been viewed primarily as an industrial feedstock. However, its potential as an energy carrier and hydrogen transport medium is now attracting significant attention as governments and organisations seek opportunities in the transition to a lower-carbon economy.

Non-captive ammonia, produced and sold into wider markets rather than consumed at the point of manufacture, is increasingly recognised as a key enabler for decarbonisation across sectors such as maritime shipping, industrial chemicals and energy storage. Despite its importance, few countries manufacture significant quantities of ammonia; the UK, for example, no longer manufactures it at all, creating a strategic dependency on imports.

Against this backdrop, electrochemical engineers Ash Stott and Ben Kyffin, the Rhizo PTX founders, left secure careers to tackle a major challenge in sustainable chemistry: a cleaner, more efficient way to manufacture ammonia.

A better way to produce ammonia

Conventional ammonia production is dominated by the energy-intensive Haber-Bosch process, which typically relies on fossil-fuel hydrogen and generates substantial carbon dioxide emissions. Green hydrogen is difficult to transport, requiring cryogenic conditions to liquefy it.

By generating ammonia directly from water and air using renewable electricity, Rhizo PTX eliminates this intermediate hydrogen step, improving efficiency and simplifying integration with renewable energy sources. At the heart of the innovation is Rhizo PTX’s proprietary electrolyser, which combines atmospheric nitrogen with water in a single electrochemical process powered by renewable electricity. This has the potential to reduce energy consumption, lower costs, cut emissions, simplify plant design and enable production in locations where traditional manufacturing infrastructure would be impractical.

The importance of accurate ammonia gas analysis

Accurate, reliable ammonia measurement has played a critically important role in developing the electrolyser. Continuous measurement with a fast response time and across a wide concentration range is essential, providing real-time process insights as the team evaluates different materials, configurations and experimental conditions. A major additional challenge is avoiding false positives while continuously quantifying the ammonia produced.

Identifying the most suitable ammonia gas analyser

The Rhizo PTX team evaluated a wide range of analytical techniques before selecting a Signal Group ammonia analyser. Colorimetric methods were considered but were non-continuous and slow. Fourier Transform Infrared Spectroscopy (FTIR), Ion Chromatography, Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Thermal Conductivity Detection (GC-TCD) were also assessed, but were generally too expensive, complex or prone to operator error.

A 2025 Ammonia Energy Association White Paper on Ammonia Gas Detection identified FTIR, Electrochemical (EC) sensing and Tunable Diode Laser Spectroscopy (TDLS) as suitable for industrial ammonia monitoring. Electrochemical sensors offer the lowest capital cost but are vulnerable to interference and poisoning, with relatively short operating lifetimes. Both FTIR and TDLS deliver continuous, accurate measurements; Rhizo PTX concluded that TDLS offered the best combination of sensitivity, reliability and cost-effectiveness.

Searching online for TDLS suppliers, the team discovered a specialist manufacturer fifteen minutes away: Signal Group. Following a successful demonstration at the Signal factory, Signal supplied the S4 NEBULA heated TDLS analyser in December 2025, and Rhizo PTX has used it successfully ever since, typically during experimental runs lasting several hours.

“We have been delighted with the NEBULA and with the support that we have received from Signal, particularly because we have been running the analyser in very high moisture conditions and with very low flow rates, both of which are, strictly speaking, outside of its specification.” — Ben Kyffin, Rhizo PTX co-founder

James Clements of Signal Group explains why the analyser performs so well: “It is essential that moisture does not condense at any point between the sampling point and the detector. For this reason, the S4 NEBULA is fully heated throughout. In addition, largely because of our work with engine emissions, our analysers have a large surface area particulate filter to improve accuracy and protect the instrument’s optics.”

Measurement stability is further enhanced through secondary filtering of the detector signal to remove electrical noise while maintaining a response time of less than three seconds. Another distinguishing feature is the removable tablet interface: rather than a fixed display, S4 analysers use a wireless tablet connecting via Wi-Fi at distances of up to 50 metres. At Rhizo PTX, the system is installed at floor level, so researchers monitor live data, alarms, datalogging and calibration from the comfort of an office chair.

Looking forward

Having demonstrated proof of concept, Rhizo PTX is now focused on scaling up. The company is designing a larger electrolyser capable of generating up to 1kg of ammonia per day, reducing experimental uncertainty while providing valuable data on process efficiency and scalability.

With the benchtop demonstrator validated at TRL4 (technology readiness level 4), Rhizo PTX is raising further investment to scale up a minimum viable product for customer pilots, producing several kilos of ammonia per day at TRL6. As development progresses, the NEBULA’s role will evolve from research tool to emissions and process monitoring instrument, helping quantify production efficiency and support commercialisation.

Summary

The S4 NEBULA has enabled Rhizo PTX to refine and develop its patent-protected, one-step ammonia production process, which eliminates separate hydrogen generation and integrates naturally with renewable energy. As the team builds a larger electrolyser, the analyser will help measure production and compare efficiency and sustainability with hydrogen-based alternatives.

Rhizo PTX’s long-term goal is a sustainable solution for non-captive ammonia production, with key markets including industrial chemicals, maritime shipping, and ammonia-based hydrogen transport and cracking systems. Beyond energy applications, ammonia remains an essential feedstock for fertilisers, explosives, plastics and synthetic fibres.

“This technology is really exciting,” says Rhizo PTX CEO Ash Stott. “Not only will this become a fast-growing, highly profitable business, but once we have demonstrated scalability, our technology will contribute greatly to the decarbonisation of hard-to-abate industries. This innovation represents a great opportunity for hardware tech impact investors.”

Email: [email protected]

Web: www.signal-group.com