Designs for green ammonia plant become a reality

The new facility is designed to function with the intermittent power supply that
The new facility is designed to function with the intermittent power supply that comes from solar and wind energy.

Researchers from the Institute for Sustainability are helping to build a small-scale plant to generate ammonia using only renewable energy sources.

Ammonia is a promising carbon-free fuel source of the future and so if successful, the plant has the potential to considerably advance the UK-s net zero ambitions.

It marks the second phase of the Ammonia Synthesis Plant from Intermittent Renewable Energy (ASPIRE) initiative which will be led by STFC in conjunction with the University of Bath, Johnson Matthey, and Frazer-Nash Consultancy.

The journey to net zero

The first phase of the ASPIRE initiative was funded as part of the UK government’s Low Carbon Hydrogen Supply two competition, which is part of the £1 billion Net Zero Innovation Portfolio.

This funding enabled the creation of a concept plant design which included novel flexible green ammonia synthesis technology.

Now, thanks to a further investment of £4.28 million by the Department for Energy Security and Net Zero , this design will be used to develop a small demonstration plant at the STFC Rutherford Appleton Laboratory in Oxfordshire.

Innovative new technology

Current commercial ammonia synthesis is optimised for near steady production requiring constant power.

The first phase of ASPIRE however saw the design of a patented modular reactor and thermal management system that should enable operation from an intermittent renewable power supply.

The new plant will have three core elements:

  • a pressure swing adsorption system which extracts nitrogen from air
  • a modular electrolyser which splits hydrogen from water
  • a synthesis loop that uses the modular reactor and a thermal management system to combine hydrogen and nitrogen to make ammonia

This will enable the entire production process to operate autonomously, powered by a small wind turbine and series of solar canopies with an ammonia generation rate proportional to the available renewable power.

Energy production of the future

Green ammonia can be used directly as a fuel in internal combustion engines including gas turbines and in fuel cells and it can also be cracked to release hydrogen for use in hydrogen fuelling stations.

Modularity and scalability are at the heart of ASPIRE and the underlying principles of the plant have been designed to be rapidly scaled up to meet industry needs.

As a result, this next phase could form the basis for large-scale off-grid green ammonia supply as well as a low carbon, economically viable hydrogen supply solution.

Unlocking potential

Dr Tristan Davenne, Principal Engineer at the STFC Energy Research Unit and ASPIRE Project Lead, said: -Ammonia is now widely considered as a promising carbon free fuel and hydrogen carrier.

-It is easier to store and transport than fuels such as hydrogen, has an established distribution network and in addition to its traditional use as fertiliser could be key to decarbonising several sectors from shipping to non-electrified rail to hydrogen fuelling stations.

-We-ve been unable to unlock its full potential though due to current carbon intensive production processes which significantly contribute to global carbon emissions.

-If this prototype plant proves successful and we can sufficiently scale up production, we can completely remove this barrier and start to build the foundation of a green ammonia economy to decarbonise large swathes of society.-

A collaborative effort

STFC’s Executive Director for National Laboratories: Large Scale Facilities, Dr Alan Partridge, said: -The development of entirely new technologies will be necessary to avoid the worst effects of climate change while enabling us to continue with our current way of life.

-ASPIRE is a prime example of the work being done by STFC to rethink essential processes, such as fuel production, to power society with net zero emissions.

-Thanks to the incredible work on this initiative by the team at Rutherford Appleton Laboratory as well as the University of Bath and private sector partners, we are closer than ever to producing industry-scale green ammonia for the UK and the world.-

An important step forward

Dr Alfred Hill, Lecturer in Chemical Engineering and ASPIRE lead at the Institute for Sustainability at the University of Bath, said: -The ASPIRE green ammonia concept is highly innovative in its design for transient operation.

-This feature will maximise capture of intermittent renewable energy and utilise it for manufacture of a critically important chemical and a zero-carbon energy vector.

-This is a big step forward for future manufacturing of chemicals from intermittent renewable resources.-