South Korea Builds an Ammonia Route to Cleaner Hydrogen

A reactor at 600 C points to a different hydrogen supply chain

South Korean researchers have demonstrated an ammonia reactor operating near 600 C, or 1,112 degrees Fahrenheit, that produces hydrogen with 99.97 percent purity without burning fossil fuels during conversion. At the Korea Institute of Energy Research (KIER), the project connects two challenges facing cleaner energy: producing hydrogen with fewer carbon emissions and moving it to the places that need it.

Ammonia, a chemical widely used to make fertilizer, carries hydrogen within its molecules. Heating it with a catalyst splits those molecules into hydrogen and nitrogen. KIER then purifies the hydrogen for fuel cells, devices that can supply electricity to vehicles or buildings.

As of November 10, 2025, the reactor sits within a wider Korean effort involving ammonia cracking trials in Ulsan, an engine that burns ammonia directly, new designs for ships carrying liquid hydrogen, and a Hyundai Motor factory scheduled for completion in 2027. Each project addresses a different part of the journey from producing fuel to delivering and using it.

Hydrogen already powers cars, buses, trains, ships, and airplanes conducting test flights. Most hydrogen, however, is still produced from natural gas through steam methane reforming, a process that releases carbon dioxide. Water electrolysis, which uses electricity to split water into hydrogen and oxygen, offers a cleaner production route when powered by wind or solar energy.

South Korea's ammonia work tackles the transport problem alongside production. Hydrogen has very low density, so moving useful quantities over long distances requires compression or liquefaction at extremely low temperatures. Ammonia offers another route: ship the hydrogen inside a more manageable chemical, then release it near the customer.

How KIER separates hydrogen from ammonia

KIER's reactor uses a simple chemical reaction with demanding operating conditions. Ammonia has the formula NH3, meaning each molecule contains one nitrogen atom and three hydrogen atoms. When ammonia breaks apart, two molecules produce one molecule of nitrogen gas and three molecules of hydrogen gas.

Ruthenium, a precious metal related to platinum, helps the reaction proceed. Such a material is called a catalyst because it helps a chemical reaction take place. Ruthenium is a common choice for ammonia cracking because it performs well at temperatures around 600 C. KIER uses that catalytic route before a further purification stage.

The gas leaving the cracker contains hydrogen, nitrogen, and traces of ammonia that have not reacted. Fuel cells need a much cleaner supply, so the system uses pressure swing adsorption, a separation method already used in refineries.

Pressure swing adsorption passes gas through beds of porous material that capture contaminants under pressure. Lowering the pressure allows the beds to release the captured material and regenerate. Several beds take turns separating gases and regenerating, providing a steady stream of highly purified hydrogen.

KIER describes the equipment as a reactor housed in a square metal frame, with pipes, hoses, gauges, and cylinders. Its control system recycles part of the process gases to help maintain the required temperature without firing a burner that consumes hydrocarbons, the main components of fossil fuels. This avoids direct carbon dioxide emissions at the conversion stage.

The institute's stated aim is to reduce carbon dioxide across the hydrogen supply chain while using materials and processes that can be expanded to larger operations. Producing hydrogen at 99.97 percent purity is one part of that effort; making the system practical at greater scale is another.

Why ammonia is easier to move than hydrogen

Liquid hydrogen must be kept at about minus 253 C. Ships and storage facilities therefore need specialized tanks to maintain extremely cold conditions, and operators must manage losses when some liquid warms and turns back into gas. Building and operating this transport system requires substantial investment.

Ammonia liquefies at about minus 33 C or under modest pressure. The chemical industry already ships it around the world in large volumes, giving energy companies an existing transport network on which to build.

For a hydrogen supply chain, the proposed sequence is straightforward. Producers use renewable energy where it is inexpensive to make hydrogen and synthesize ammonia. Ships carry the ammonia to a market with large energy demand. A cracking plant at the destination releases hydrogen for local users.

Japan and South Korea have expressed interest in importing green ammonia linked to wind and solar projects. The attraction is the ability to connect locations with abundant renewable power to industrial markets where demand is high, using a molecule that is easier to store and transport than hydrogen itself.

What the Ulsan cracking trial achieved

Syzygy Plasmonics and Lotte Chemical have tested an ammonia cracking system powered entirely by electricity in Ulsan. The unit achieved 81 percent energy efficiency and converted 99 percent of the ammonia, while producing roughly 290 kilograms of hydrogen a day.

The trial reported energy consumption of about 11 kilowatt hours for each kilogram of hydrogen produced. Designs target a reduction to 8 kilowatt hours per kilogram. The partners plan to develop a small commercial plant to supply local demand, although no opening date was given.

The two energy figures show the size of the planned improvement. Reducing consumption from 11 to 8 kilowatt hours would save 3 kilowatt hours per kilogram, a reduction of about 27 percent. At the trial's output of roughly 290 kilograms a day, that difference would amount to about 870 kilowatt hours daily if output stayed the same.

Hydrogen's lower heating value, a measure of its usable energy content, is roughly 33 kilowatt hours per kilogram. The reported cracking requirement of 11 kilowatt hours is therefore about one third of that amount, while the target of 8 is about one quarter. Those figures help explain why reducing the energy needed to release hydrogen matters to operating costs.

Better catalysts, more effective reuse of heat, and improvements in electric heating can reduce the energy penalty of cracking ammonia. Systems powered entirely by electricity also make it easier to use wind and solar energy for the conversion process. The Ulsan results provide practical evidence for an import route that could serve South Korea, Japan, and other regions with large energy needs.

Where purified hydrogen could be used first

Fuel cell vehicles require very clean hydrogen because the catalysts inside polymer electrolyte membrane stacks are sensitive to impurities. These stacks use a membrane as part of the process that turns hydrogen into electricity. KIER's reported purity of 99.97 percent aligns with the needs of this technology.

Regional hubs are a likely route for deployment. Such facilities could receive ammonia, crack it locally, and distribute purified hydrogen to fueling stations. Shipyards, ports, and logistics parks are natural candidates because they already handle hazardous materials and large flows of energy.

Buildings are another possible destination. KIER is studying hydrogen fuel cells for buildings, suggesting that stationary electricity generation could develop alongside transport applications. A local hydrogen supply could therefore serve more than one type of customer.

The different uses make purification a central part of the proposed supply chain. Transporting ammonia solves one problem, while delivering hydrogen clean enough for sensitive fuel cell equipment requires the additional separation stage demonstrated by KIER.

A separate engine route uses ammonia directly

The Korea Institute of Machinery and Materials (KIMM), Hyundai Motor, and Kia are also pursuing a route that does not require ammonia to be converted into hydrogen first. A coalition led by KIMM unveiled a high pressure engine that injects pure ammonia directly into its combustion chamber.

The team improved stability and power by coordinating fuel injection in several stages with variable valve timing and a strengthened ignition system. Variable valve timing adjusts when engine valves open and close, helping control how the engine takes in and expels gases.

A proprietary exhaust treatment package reduces nitrogen oxides and unburned ammonia. Nitrogen oxides are air pollutants, while ammonia escaping without being burned creates another emissions concern. Exhaust treatment is therefore part of the engine design, alongside the equipment needed to make combustion stable.

Direct injection removes the need for a gaseous ammonia reformer, simplifying some applications. The engine is being positioned for marine propulsion, power generation away from electricity grids, and heavy vehicles. Deployment plans for 2027 are under review.

KIMM's engine and KIER's cracker serve different users. One burns ammonia to produce mechanical power; the other releases hydrogen for equipment such as fuel cells. Both depend on reliable ammonia supplies and careful control of the risks associated with handling the chemical.

Ships and tanks offer another transport option

HD Korea Shipbuilding and Offshore Engineering (HD KSOE) has secured Approval in Principle from the American Bureau of Shipping for a hydrogen carrier tank that uses vacuum insulation. The tank is designed to maintain the cryogenic conditions needed for liquid hydrogen, near minus 253 C.

The company and its partners are studying a liquefied hydrogen carrier with a capacity of 80,000 cubic meters. Work on these specialized tanks is taking place alongside the use of existing ammonia carriers, allowing the two transport approaches to develop in parallel.

HD KSOE executives described the tank milestone as part of a broader effort to reduce carbon emissions from energy shipping. They stated:

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

Ammonia transport and liquid hydrogen transport place different demands on ships and storage equipment. Ammonia benefits from an established global shipping network, while liquid hydrogen requires equipment that can handle much colder temperatures. South Korea is advancing both routes as companies work toward complete fuel supply chains.

Hyundai's Ulsan factory and the 2027 milestones

Hyundai Motor has begun construction of a new Ulsan facility to manufacture next generation hydrogen fuel cells and polymer electrolyte membrane electrolyzers. The investment exceeds $644 million.

The factory is scheduled for completion in 2027, with planned annual production of about 30,000 fuel cell units. Hyundai aims to improve performance and cost while locating key hydrogen production technologies inside South Korea.

Fuel cells and electrolyzers perform different jobs. Fuel cells use hydrogen to generate electricity, while electrolyzers use electricity to produce hydrogen from water. Manufacturing both places the new facility at the production and consumption ends of the hydrogen economy.

The projects have different schedules and levels of readiness. The main dated milestones are:

• November 10, 2025: South Korea's hydrogen effort includes the reported KIER reactor demonstration, the Ulsan electric cracking trial, the ammonia engine unveiling, the hydrogen tank approval, and Hyundai's factory construction.
• 2027: Hyundai's Ulsan facility is scheduled for completion, with planned capacity for about 30,000 fuel cell units a year.
• 2027: Deployment plans for the KIMM, Hyundai, and Kia ammonia engine are under review.

The combination of manufacturing investment, new tanks, and engine development shows how pilot projects could connect to a broader industrial supply chain. The cracking plant planned by Syzygy and Lotte would add a local source of hydrogen to that network.

Korean laboratories pursue other production methods

KIMM has developed a solid oxide electrolysis system rated at 20 kilowatts that produced hydrogen efficiently for more than 3,000 hours. This method operates at high temperature, allowing it to use heat from industrial processes to reduce electricity consumption.

Steel mills and chemical plants are potential partners for that approach because their processes can provide useful heat. The project offers another route to producing hydrogen, alongside electrolysis powered by renewable electricity and the use of ammonia as a transport carrier.

KIER scientists have also reported a catalyst that converts carbon dioxide into carbon monoxide, a key ingredient for synthetic fuels. Academic groups have demonstrated routes to green ammonia at room temperature using electrochemical cells.

These projects address different chemical steps. Some produce hydrogen, some aim to make ammonia, and another converts carbon dioxide into a building block for fuels. Together, they show the range of technologies being explored as South Korea seeks cleaner fuel production and supply.

The climate benefit starts before the ship leaves

Ammonia's production method determines much of its climate value. Ammonia made from hydrogen derived from fossil fuels carries a large carbon footprint. When that ammonia is later cracked into hydrogen, the emissions from producing it remain part of the fuel's supply chain.

KIER's avoidance of a hydrocarbon burner addresses direct emissions during conversion. A cleaner chain also requires attention to the energy used to make ammonia, transport it, and release the hydrogen. Green ammonia connected to wind and solar projects is intended to address the production part of that chain.

Co firing ammonia or hydrogen in coal or gas power stations has also drawn caution because the full energy and logistics costs can leave relatively small climate benefits. The strongest early uses identified for hydrogen include steelmaking, chemicals, ocean shipping, and seasonal energy storage, sectors where using electricity directly can be difficult.

Korean planners are weighing those trade offs as they develop targets and standards. Choosing where hydrogen is used matters alongside choosing how it is produced and delivered.

Ammonia handling also demands monitoring, ventilation, and emergency plans because the chemical is toxic and has a strong odor. Engines need exhaust treatment to control nitrogen oxides, while cracking facilities must watch catalyst and membrane durability and maintain compressors and pumps.

The practical measures to watch are specific: electricity consumption per kilogram of hydrogen, reliable purification, control of engine emissions, safe ammonia handling, and access to green ammonia. Larger demonstrations will help show how the reactors, ships, factories, and end users can operate together.

Key Points

• KIER demonstrated ammonia cracking near 600 C, producing hydrogen with 99.97 percent purity without burning fossil fuels during conversion.
• The reactor uses a ruthenium catalyst, pressure swing adsorption, and recycled process gases.
• Syzygy Plasmonics and Lotte Chemical's Ulsan trial achieved 81 percent efficiency, 99 percent conversion, and roughly 290 kilograms of hydrogen daily.
• The Ulsan system used about 11 kilowatt hours per kilogram of hydrogen, with designs targeting 8.
• KIMM, Hyundai, and Kia unveiled an engine using pure ammonia, with deployment plans for 2027 under review.
• HD KSOE secured Approval in Principle for a liquid hydrogen tank and is studying a carrier of 80,000 cubic meters.
• Hyundai's Ulsan factory represents an investment exceeding $644 million and is scheduled for completion in 2027.
• Cleaner hydrogen depends on ammonia production, conversion energy, shipping, safety, and the choice of end use.