The Future of Advanced Air Mobility

UK Consortium Proposes Ammonia-based Propulsion System for Aircraft

Ammonia this week surfaced as a new contender in the contest to develop a zero-carbon fuel for aircraft. A consortium led by UK-based Reaction Engines on November 5 announced plans to develop a propulsion system using lightweight and compact catalytic cracker reactors to generate hydrogen, producing a fuel that could then be burned directly in turbine engines.

The partners aim to commercialize the new propulsion concept in aircraft, as well as marine and other industrial applications, by 2030. The process combines the heat exchanger technology developed by Reaction Engines for its Synergetic Air-Breathing Rocket Engine (SABRE) developed for space launch vehicles with ammonia catalyst systems from the Science and Technology Facilities Council (STFC). Venture capital group IP Group is providing an undisclosed investment in the program.

“After completing STFC-funded proof-of-concept projects, 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, senior fellow and professor of energy materials chemistry at Oxford University. “Plating to the complementary strengths of ammonia and hydrogen, our cracker technology can rely on global ammonia infrastructure to provide, at scale, blended ammonia-hydrogen fuels that mimic fossil fuel performance and offer affordable retrofitted energy solutions.”

In a press conference held alongside the United Nations COP26 climate change conference in Scotland, the partners explained that their solution will use green ammonia produced by combining water and air using renewable energy. Most of the world’s ammonia supplies today are produced from an energy-intensive process burning fossil fuels.

According to Hamish Nichol, Reaction Engines sector lead for applied technologies, the fuel produced by the ammonia-cracking process would be stored in aircraft wings that, for retrofit applications, would have to be adapted for this purpose. He said the partners are aiming to support a range of up to around 2,000 km (1,250 miles). They want to partner with Tier 1 aerospace manufacturing companies to integrate the technology with aircraft and their propulsion hardware.

Reaction Engines was co-founded in 1989 by Alan Bond and two partners after the HOTOL (Horizontal Take Off and Landing) project foundered. The company refined its engine and launch vehicle designs over the following two decades, with support from private investors. The designs eventually gained technical endorsement from the European Space Agency (ESA) and the U.S. Air Force Research Laboratory (AFRL).

In 2013 the UK Space Agency agreed to provide a £61 million (US$80 million) grant of government money. In 2015, BAE Systems made a “strategic investment” of £21.6 million (US$28.4 million). Boeing, Rolls-Royce, and more private investors have since pitched in. Now the company is looking to diversify from the space sector.