Ammonia to Hydrogen: How South Korea is building a cleaner fuel supply chain

Why South Korean researchers are betting on ammonia to unlock clean hydrogen

South Korean scientists have demonstrated a way to produce hydrogen without burning fossil fuels by breaking ammonia into hydrogen and nitrogen at high temperature. At the Korea Institute of Energy Research, engineers report a reactor that runs near 1,112 degrees Fahrenheit (about 600 C) and delivers hydrogen with 99.97 percent purity. That output is suitable for fuel cells that can power vehicles or buildings. The project aims to cut carbon dioxide from the hydrogen supply chain while using materials and processes that can scale.

Hydrogen is already used in trains, airplanes for test flights, cars, buses, and ships. Yet most hydrogen today is made from natural gas through steam methane reforming, which releases carbon dioxide. Clean production routes are growing, including water electrolysis powered by wind and solar. Moving hydrogen is the other challenge. The gas has very low density, so it must be compressed or liquefied at ultracold temperatures to ship long distances. Ammonia, the familiar chemical for fertilizer, offers a workaround. It is a liquid under moderate conditions and carries hydrogen in its molecular bonds. If ammonia can be cracked at the destination into clean hydrogen and nitrogen, it becomes a practical bridge between places with abundant renewable power and places with large demand.

Inside the KIER reactor: turning ammonia into fuel grade hydrogen

Ammonia cracking is straightforward chemistry. Molecules of ammonia, NH3, split into hydrogen and nitrogen when heated in the presence of a catalyst. In a balanced reaction, two molecules of ammonia form one molecule of nitrogen and three molecules of hydrogen. Ruthenium, a precious metal related to platinum, is a common catalyst choice because it performs well at temperatures around 600 C. The KIER setup uses that catalytic pathway, then polishes the gas stream to reach fuel cell grade hydrogen.

As hydrogen leaves the cracker, it is mixed with nitrogen and traces of unreacted ammonia. Pressure swing adsorption, a standard purification step in refineries, separates the gases. Beds of porous materials capture contaminants at pressure and release high purity hydrogen when the pressure is lowered. A series of beds cycle between adsorption and regeneration to provide a steady output. KIER describes a reactor housed in a square metal frame with pipes, hoses, gauges, and cylinders, and a control scheme that recycles a portion of process gases to sustain high temperatures without firing a hydrocarbon burner. That approach avoids direct carbon dioxide at the point of conversion.

Why ammonia is a powerful hydrogen carrier

Hydrogen is tricky to store and ship. Liquid hydrogen requires cryogenic tanks at about minus 253 C. Boil off losses must be managed, and transport is capital intensive. Ammonia liquefies at about minus 33 C or under modest pressure. The chemical industry already moves it around the world in large volumes. For energy, that means producers can synthesize ammonia where renewable power is cheap, send it by ship, and crack it near end users.

Industrial trials in South Korea are building credibility for this model. Syzygy Plasmonics and Lotte Chemical have tested an all electric ammonia cracking system in Ulsan. The unit achieved 81 percent energy efficiency, 99 percent conversion, and produced roughly 290 kilograms per day of hydrogen. Reported energy use was about 11 kilowatt hours per kilogram of hydrogen, with designs targeting 8 kWh per kilogram. The partners plan to develop a small commercial plant to supply local demand. Results like these point to an import pathway that could serve Korea, Japan, and other energy hungry regions.

From lab to roads and ships: how this could change transport

Fuel cell vehicles require very clean hydrogen because catalysts in polymer electrolyte membrane stacks are sensitive to impurities. The 99.97 percent purity KIER reports aligns with those needs. A likely deployment path is regional hubs that receive ammonia, crack it on site, and distribute purified hydrogen to fueling stations. Shipyards, ports, and logistics parks are natural locations for early systems, since they already handle hazardous materials and large energy flows.

Engines that run on ammonia directly

Engineers in Korea are also exploring direct use of ammonia as a fuel. A coalition led by the Korea Institute of Machinery and Materials with Hyundai Motor and Kia unveiled a high pressure engine that injects pure ammonia straight into the combustion chamber. The team improved stability and power by synchronizing multi stage fuel injection with variable valve timing and a strengthened ignition system. A proprietary after treatment package cuts nitrogen oxides and unburned ammonia to address air quality. The design removes the need for a gaseous ammonia reformer, which simplifies some applications. It is being positioned for marine propulsion, off grid power, and heavy duty vehicles, with deployment plans under review for 2027.

Building the supply chain: ships, tanks, and factories

Large scale hydrogen trade will rely on specialized vessels and storage. HD Korea Shipbuilding and Offshore Engineering secured Approval in Principle from the American Bureau of Shipping for a hydrogen carrier tank that uses vacuum insulation to hold cryogenic temperatures near minus 253 C. The company and partners are studying an 80,000 cubic meter liquefied hydrogen carrier. Progress on tanks for liquefied hydrogen sits alongside the existing fleet of ammonia carriers, which can support energy shipments in parallel.

Manufacturing capacity on land is ramping up as well. Hyundai Motor began building a new facility in Ulsan to produce next generation hydrogen fuel cells and polymer electrolyte membrane electrolyzers. The project represents an investment of more than 644 million dollars. The plant is scheduled to be complete in 2027 and to turn out about 30,000 fuel cell units each year. The plan is to improve performance and cost, and to locate key technologies for hydrogen production inside Korea.

What industry leaders are saying

HD KSOE executives view the tank milestone as part of a broader push to decarbonize energy shipping.

“We will continue collaborating with leading global companies to drive the energy transition and achieve net-zero goals.”

The combination of new tanks, engines, and fuel cell manufacturing points to a coordinated effort to turn pilot projects into full supply chains.

Clean hydrogen production is diversifying in Korea

Korean laboratories are advancing multiple clean hydrogen pathways. The Korea Institute of Machinery and Materials developed a 20 kilowatt solid oxide electrolysis system that produced hydrogen efficiently for more than 3,000 hours. Solid oxide electrolysis runs hot, which lets it use heat from industrial processes to cut electricity consumption. That approach can pair well with steel mills and chemical plants.

Other teams are pursuing complementary chemistry. Scientists at KIER reported a catalyst that converts carbon dioxide into carbon monoxide, a key ingredient for synthetic fuels. Academic groups have demonstrated room temperature routes to green ammonia using electrochemical cells. Countries including Japan and Korea have signaled interest in importing green ammonia linked to wind and solar projects, since the molecule is easier to store and ship than hydrogen.

Ammonia must be clean to unlock climate gains

There is an important caveat. Ammonia made from fossil hydrogen carries a large carbon footprint. Cracking that ammonia at the destination does not remove those upstream emissions. Analysts also caution that co firing ammonia or hydrogen in coal or gas power stations produces small climate benefits once the full energy and logistics costs are counted. The strongest early use cases for hydrogen are in sectors that are hard to electrify, such as steel, chemicals, ocean shipping, and seasonal energy storage. Korean planners are weighing those trade offs as they set targets and standards.

Risks, efficiencies, and what to watch next

Energy use is a key metric. The Ulsan cracker trial reported about 11 kilowatt hours per kilogram of hydrogen, with designs targeting 8 kWh per kilogram. The lower figure would bring costs down. For context, the lower heating value of hydrogen is roughly 33 kilowatt hours per kilogram. Improving catalysts, heat integration, and electric heating can reduce the energy penalty for cracking.

Safety and emissions require careful design. Ammonia is toxic and has a strong odor, so operators will need monitoring, ventilation, and emergency plans. When used in engines, after treatment is needed to control nitrogen oxides. Operators will watch durability for catalysts and membranes, and maintenance schedules for compressors and pumps. Companies are designing cracking systems that run entirely on electricity, which makes it easier to power them with wind and solar. KIER is also studying hydrogen fuel cells for buildings, a sign that transport and stationary power may grow together.

Key Points

• KIER demonstrated ammonia cracking near 600 C that delivers 99.97 percent pure hydrogen without burning fossil fuels at the point of conversion.
• The process uses a ruthenium catalyst and pressure swing adsorption to purify hydrogen for fuel cells.
• Syzygy and Lotte tested an all electric cracker in Ulsan with 81 percent efficiency, 99 percent conversion, about 290 kilograms per day of output, and energy use near 11 kWh per kilogram with designs targeting 8.
• Ammonia serves as a practical hydrogen carrier because it liquefies under moderate conditions and has a mature global shipping infrastructure.
• KIMM, Hyundai, and Kia unveiled a high pressure engine that runs on pure ammonia with after treatment to curb emissions, aimed at marine, off grid, and heavy duty uses by 2027.
• HD KSOE received Approval in Principle for a large liquid hydrogen tank and is studying an 80,000 cubic meter carrier concept.
• Hyundai is building a 644 million dollar plant in Ulsan to produce fuel cells and polymer electrolyte membrane electrolyzers, with a goal of 30,000 fuel cell units a year by 2027.
• Korea is also advancing solid oxide electrolysis for green hydrogen and catalysts to turn carbon dioxide into building blocks for clean fuels.
• Analysts caution that co firing hydrogen or ammonia in fossil power plants offers limited climate benefits once supply chain energy is counted, so priority uses include steel, chemicals, shipping, and seasonal storage.
• Key watch items include cracking energy per kilogram, nitrogen oxides control, safety practices for ammonia handling, sourcing green ammonia, and large scale demonstrations.