Ammonia as a Green Hydrogen Carrier

By | June 24, 2020

The UK’s Department for Business, Energy and Industrial Strategy (BEIS) recently published the feasibility study for its Ammonia to Green Hydrogen Project.

A number of liquid “hydrogen carriers” have been considered to enable hydrogen to be transported over long distances at low cost. This is will enable green hydrogen to be produced from very low cost renewables and carried, in bulk, to locations of high energy demand which are often hundreds or thousands of miles away from its source.

Ammonia (NH3) is a front runner for this role, as it has a high hydrogen content and can already be produced from hydrogen, at very large scale and low cost in the Haber-Bosch process, first demonstrated in 1914. 

Liquid ammonia, which has physical properties similar to liquefied petroleum gas (LPG) is routinely transported by road, rail and sea and the study estimates the cost of shipping it in bulk, 6,000 miles from the Middle East to the UK, to be as little as £0.18/kg of hydrogen.   

Once delivered to the point of end use, the liquid ammonia has to be converted back into hydrogen and nitrogen in a catalysed cracking process. The technology to do this cost effectively is still in the development stage but a process designed by ENGIE can achieve this at the site of the end-user.  In addition, The UK Science & Technology Facilities Council (STFC), has developed and modelled a design for a cracker with a novel lithium imide-based catalyst which will enable lower temperature, higher efficiency operation.  

The study concludes that the use of ammonia as a hydrogen carrier is technically feasible. It also concludes that and that the economics for importing green hydrogen to the UK from the Middle East can compare favourably with the production of green hydrogen in the UK  and transporting it as gaseous hydrogen to end-users by road. 

Authors

The study has been produced by a high-profile consortium including ENGIE, Siemens, Ecuity Consulting, and the UK Science & Technology Facilities Council (STFC). Kevin Fothergill and Peter Gray from EnAcumen provided key inputs to the assessment of the technology, market and economics. 

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