A new process that could enable zero-carbon flights using liquid ammonia is being unveiled at Cop26.

Thus far, hydrogen has been seen as the only potential “clean” fuel for the future of aviation (alongside battery-operated aircraft).

One of the stumbling blocks is that completely different aircraft and infrastructure would be needed to accommodate storing hydrogen, either as a gas or in extremely cold liquid form.

But a British venture from Oxford University scientists and rocket engine technology firm Reaction Engines is proposing using “cracked” ammonia, arguing that existing planes could use it as fuel – with some modifications – by 2030.

Commercial aircraft could be retrofitted with small reactors, according to scientists, allowing hydrogen to be converted from ammonia and used as jet fuel.

“I am excited about the impact that our technology can have in enabling low-impact transitions in hard-to-abate energy sectors,” said Bill David, STFC senior fellow and professor of energy materials chemistry at Oxford.

“Playing to the complementary strengths of ammonia and hydrogen, our cracker technology can rely on the global ammonia infrastructure to provide, at scale, blended ammonia-hydrogen fuels that mimic fossil fuel performance and offer affordable retrofitted energy solutions.”

Seed funding is coming from cleantech investor IP Group.

Robert Trezona, head of Cleantech, IP Group, called the process “a profound breakthrough” and “a credible, amazing combination of science and engineering”.

There are currently a number of obstacles standing in the way of scaling up the use of ammonia, one of which is cost – the price of ammonia far exceeds that of kerosene.

On top of that, the ammonia “cracking” process produces nitrous oxides emissions as well as the desired hydrogen.

These are greenhouse gases that also have a significant warming impact.

However, Mr David said the team were “on a journey”, and were working to demonstrate how these emissions could be lessened as the process is honed.

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