Green Ammonia: Key to a Climate-Neutral Energy Future

The global energy transition requires not only a shift to renewable energy sources, but above all practical solutions for the storage and transport of this energy. Electricity from wind and solar is volatile – its availability fluctuates significantly depending on the time of day, weather conditions, and season. To ensure a reliable and stable energy supply, suitable energy carriers must be developed that store surplus energy and make it available as needed.

Hydrogen: A promising solution with challenges

In this context, green hydrogen is seen as a key technology. It can be produced by electrolysis of water using renewable energy and can be used in many ways – whether in industry, transportation, or reconversion to electricity. However, practical implementation faces significant challenges:

• Low volumetric energy density requires complex compression or liquefaction.

• Strict safety requirements when handling the highly flammable gas.

• Lack of infrastructure for large-scale transport, distribution, and storage.

Green ammonia as a solution

A promising alternative is green ammonia (NH₃), a molecular energy carrier that is carbon-free and, in contrast to hydrogen, can be easily liquefied, transported, and stored. It is produced by synthesizing:

• Green hydrogen, generated by electrolysis of water (using wind or solar power),

• and nitrogen, extracted directly from the surrounding air.

The synthesis process is based on the proven Haber-Bosch process, which is already widely used worldwide for the production of conventional ammonia – although typically based on fossil raw materials. By switching to green feedstocks and renewable energy, the result is a CO₂-neutral energy carrier.

→ Why ammonia?

Ammonia (NH₃) possesses several properties that make it particularly interesting:

Ammonia (NH₃) is increasingly coming into focus as a versatile energy carrier in the search for viable solutions for a carbon-neutral economy. Originally known primarily as a base chemical in fertilizer production, the compound is now gaining importance beyond the chemical industry. Ammonia combines several physical and chemical properties that make it a particularly attractive candidate for the energy transition:

First, ammonia is completely carbon-free – it contains no carbon atoms and emits no CO₂ when burned. This makes it a clean alternative fuel in applications where direct use of hydrogen is technically or economically impractical.

Second, it has a higher volumetric energy density than hydrogen gas and can be liquefied under moderate conditions (−33 °C at atmospheric pressure). This makes it significantly easier and more efficient to store and transport – for example, in insulated tank containers or ships.

A third advantage: the infrastructure for storage, handling, and transport already exists worldwide. Millions of tons of ammonia are traded annually as a chemical raw material. This existing logistics infrastructure can also be used for green ammonia in the future, reducing investment costs and accelerating market adoption.

In addition, ammonia is an excellent hydrogen carrier: the bound hydrogen can be released again when needed through thermochemical processes – a process known as “cracking.” This offers a practical way to transport hydrogen over long distances without relying on complex cryogenic or high-pressure technology.

Finally, ammonia is extremely versatile in use: in addition to its role in fertilizer production, it can be used for electricity and heat generation, in fuel cells, as shipping fuel, or as a process gas in industry.

This combination of technical advantages, infrastructure availability, and flexibility makes ammonia a key enabler for the global transformation of our energy systems.

→ Production of Green Ammonia

The industrial production of ammonia has been shaped by the Haber-Bosch process for over a century – an energy-intensive process operated on a large scale worldwide. While conventional (grey) ammonia is mainly based on fossil energy sources such as natural gas, the green variant relies entirely on renewable energy. This marks an important step toward the decarbonization of the chemical and energy industries.

1. Production of Green Hydrogen

The key foundation for green ammonia is green hydrogen. It is produced via electrolysis – a process that splits water (H₂O) into hydrogen (H₂) and oxygen (O₂). The electricity required comes entirely from renewable sources, typically:

• Photovoltaic systems (solar energy)

• Wind farms

• Hydropower plants

Since no fossil fuels are used, hydrogen production is CO₂-free – unlike conventional steam reforming, where natural gas is split with the release of large amounts of CO₂.

Overview of electrolysis methods:

• Alkaline Electrolysis (AEL): Technically mature, suitable for large-scale production.

• PEM Electrolysis (Proton Exchange Membrane): Fast response, ideal for fluctuating power supply.

• Solid Oxide Electrolysis (SOEC): Promising for future high-temperature applications.

2. Nitrogen Extraction from Air

In addition to hydrogen, nitrogen (N₂) is required – extracted from ambient air via cryogenic distillation or membrane separation. Both methods are relatively energy-efficient and well established.

3. Haber-Bosch Synthesis with Green Power

Next, hydrogen and nitrogen are combined via the Haber-Bosch process at temperatures of 400–500 °C and pressures of 150–300 bar to produce ammonia (NH₃):

Whereas conventional ammonia synthesis relies on fossil fuels (e.g. natural gas for steam generation), green ammonia production can be fully powered by renewable electricity and electrically heated reactors.

4. Energy Balance and System Integration

The production of green ammonia is energy-intensive, but in the context of surplus renewable energy – such as wind power in northern Germany or solar energy in North Africa – it represents a valuable storage and conversion solution. Plants can also be directly connected to solar or wind farms (“Power-to-Ammonia” projects), minimizing energy losses and grid loads.

→ Applications of Green Ammonia

Green ammonia is far more than just an alternative chemical feedstock – it has the potential to become a key element of the global energy transition. Thanks to its high energy density, existing infrastructure, and CO₂-free nature, it offers broad applicability – both as an energy carrier and as a base chemical in industrial processes.

The following application areas highlight how green ammonia can help decarbonize entire sectors of the economy:

Energy Supply

In the field of energy storage, ammonia plays a central role as a hydrogen carrier and energy medium. Surplus energy from wind or solar installations can be chemically stored via power-to-ammonia systems and recovered as electricity or heat when needed – making it an ideal component within power-to-X concepts.

• Hydrogen storage medium: Ammonia serves as a compact, transportable form of chemically stored energy.

• Direct use in gas turbines and fuel cells: Initial pilot plants demonstrate that ammonia can be used directly as a fuel – without the detour of hydrogen cracking.

• Electricity generation on demand: In so-called “X-to-power” applications, the stored energy can be fed back into the grid during times of low wind or solar availability.

Chemical Industry

As a key raw material of the chemical industry, ammonia has been produced and used on a large scale for decades – especially for fertilizer manufacturing. Green ammonia can replace conventionally produced ammonia without requiring major changes to existing processes.

• Fertilizer production: Ammonium nitrate, urea, and other nitrogen compounds can be produced from green ammonia just like from grey – but in a climate-neutral way.

• Alternative to fossil feedstocks: In other areas of basic chemistry (e.g., nitric acid or industrial gas production), green ammonia can replace fossil-based inputs.

Shipping

The maritime sector is urgently seeking low-emission fuels to meet international climate goals. Green ammonia is a promising candidate – not only climate-friendly but also logistically feasible.

• CO₂-neutral marine fuel: No carbon dioxide emissions are produced when used in ship engines.

• No particulate or sulfur emissions: A major advantage over heavy fuel oil and conventional diesel.

• Dual-fuel technologies in development: Engine manufacturers are working on solutions for ammonia-powered propulsion – first test vessels are already underway.

Decarbonizing Heavy Industry

In high-temperature industrial processes – such as cement, glass, or steel production – electrification is often not feasible. Here, ammonia can play a crucial role as a climate-neutral fuel.

• Replacement for fossil heating gases: Ammonia can be directly combusted or used as a thermal energy source.

• Use in high-temperature processes: Where temperatures above 1000 °C are required, ammonia enables a switch to CO₂-neutral heat supply.

→ Precise Measurement and Control Technology by WIKA for Green Ammonia

The production, storage, distribution, and use of green ammonia place high demands on safety, measurement, and control technology. Ammonia is not only chemically reactive, but also toxic, corrosive, highly volatile, and flammable in certain concentrations. At the same time, it must be handled under high pressure, at low temperatures, or in explosion hazard zones (Ex areas). Reliable and precise measurement technology is essential for the safe and efficient operation of such systems.

WIKA offers a comprehensive portfolio of measurement and control technology solutions specifically designed for demanding process environments, such as those encountered in the green ammonia value chain.

Pressure Measurement – Robust and Media-Resistant

Monitoring pressure is critical in every step of the process – from the synthesis reactor to pumps, compressors, and storage or transport containers.

• Mechanical and electronic pressure instruments for reliable measurement of operating, vacuum, and differential pressures

• Stainless steel housings or special materials such as Hastelloy®, Monel®, or PTFE-coated diaphragms for high resistance to ammonia

• Process connections in hygienic, standardized, or customized designs

• Optional with pressure relief devices, vibration damping, or liquid filling

Example products:

• WIKA S-20 Industrial pressure transmitter

• IS-3 Explosion-proof pressure transmitter for Zone 1/21

• PGS23.100 with electrical switch function for critical applications

Temperature Measurement – For Extreme Conditions

Ammonia is often stored at low temperatures (e.g., −33 °C at atmospheric pressure) and synthesized at high temperatures. Therefore, temperature monitoring is essential for process control and safety management.

• Resistance thermometers (e.g., Pt100) for precise temperature monitoring in storage tanks, pipelines, or reactors

• Thermocouples for high-temperature processes in synthesis or ammonia combustion

• Transmitters with HART, PROFIBUS, or IO-Link interfaces for integration into modern control systems

• Optional with intrinsic safety (Ex-i) or flameproof enclosure (Ex-d)

Example products:

• TR10 series – configurable temperature sensors with thermowell

• TC84 – particularly robust for extreme thermal loads

• T32 – digital transmitter with international SIL certification

Level Measurement – Safe and Continuous

For monitoring fill levels in storage, transport, and reaction tanks, WIKA offers various solutions:

• Hydrostatic level measurement via submersible probes or differential pressure sensors

• Magnetic float indicators with electrical signal output

• Non-contact methods (radar, ultrasonic) for contamination-free, low-maintenance operation

• Special designs for cryogenic applications, e.g., in ammonia evaporators

Sample products include:

• LF-1 – compact level sensor with IO-Link

• BNA series – magnetic level indicators with customizable switch points

Flow Measurement – For Precise Process Control

In systems transporting ammonia as a liquid or gas, flow control is a central element for energy efficiency and process safety.

• Thermal mass flow meters for gases in small to medium flow rates

• Ultrasonic or differential pressure-based systems for liquids

• Can be combined with control valves, data loggers, and remote monitoring systems

Standards, Safety, and Certifications

For global use – especially in hazardous (Ex) areas – WIKA complies with all relevant standards and regulations:

• ATEX, IECEx, CSA, UL, EAC – certified devices for hazardous zones

• SIL 2/3-compliant sensors for safety-critical applications

• ISO 9001:2015-certified manufacturing

• Devices with PED compliance for pressure equipment

Digital Integration & Remote Monitoring

In addition to classic sensor technology, WIKA also offers IoT-enabled systems for real-time monitoring, predictive maintenance, and process optimization – ideal for decentralized ammonia systems or globally networked storage and transport infrastructures.