On its ‘tech days 2023’, state-owned Chinese carmaker GAC (Guangzhou Automobile Group Co.) showed several technical ‘tour de forces’, including the world’s first passenger car engine running on ammonia. 

GAC developed a 2.0-liter engine that can burn liquid ammonia, delivering 120 kilowatts of power and a 90% reduction in carbon emissions compared to conventional fuels. Still, it doesn’t solve the problem of high nitrogen oxide (NOx) emissions.

Difficult to burn

“We’ve overcome the pain point of ammonia being difficult to burn quickly and put the fuel to use in the passenger car industry,” Qi Hongzhong from GAC’s research and development center told Bloomberg. “Its value to society and for commercial uses are worth anticipating.”

But the chance that ammonia will be used for ICE passenger cars shortly is improbable, as no refueling infrastructure is available and ammonia requires special safety measures for handling.

Burning ammonia in an internal combustion engine (ICE) is something the industry has envisioned so far for ships or heavy trucks, but not for use in passenger cars due to its low flammability and its toxic character. Those industries have more experience in the safe handling of toxic ammonia.

Marine engines

Japanese Mitsubishi Shipbuilding Co. presented an ammonia fuel supply system for marine engines in May. It was delivered to Japan Engine Corporation (J-ENG), a manufacturer of marine engines based in Akashi City. They are conducting tests of ammonia fuel under various conditions utilizing experimental, large-scale, low-speed two-stroke marine engines.

Ammonia (NH3) molecules contain one part of nitrogen and three parts of hydrogen. Today, it is mostly made from natural gas, a non-sustainable process, mainly used for fertilizers. But it has applications in far more domains like wastewater treatment, cold storage, refrigeration systems, printing and cosmetics industries, and in the production of pharmaceuticals.

Liquified at -33°C

But there is a more sustainable way. The general idea is that ‘green’ hydrogen can be made in regions like the Middle East or Chile with a lot of solar and wind power, converted to ammonia by adding nitrogen and transported in ships to Europe. Once in Europe, it can easily be reconverted into hydrogen, which can be used for fuel cell vehicles.

Ammonia has the advantage that it can be liquified at -33°C and transported in colossal ammonia tankers, similar to today’s fleet of liquified natural gas tankers. While for hydrogen to become liquid, it has to be cooled in cryogenic conditions to minus 253°C, making it more difficult and expensive to handle and distribute.

French Air Liquide announced in March it will construct an industrial-scale pilot cracker in the Port of Antwerp to convert ammonia (NH3) into hydrogen (H2). The new plant, scheduled to be operational by 2024, will be a crucial stepstone transporting green energy from sunny regions worldwide over the oceans to Europe, a vital enabler of the energy transition.