Ammonia, the energy carrier

Secret star of the energy transition: RWE invests in ammonia projects

Ammonia – a next-generation energy source?

With an annual production of 180 million tonnes globally, ammonia, a colourless gas, is one of the most important feedstocks for the chemical industry. Used as a base material for producing fertiliser, plastics and chemicals, the nitrogen-hydrogen compound is increasingly drawing the attention of the energy industry. Ammonia is widely expected to become the next-generation clean energy source because its combustion does not produce the greenhouse gas carbon dioxide. Depending on the source of the hydrogen part of the molecule, ammonia is denominated as either “blue” or “green”. If the hydrogen is generated using natural gas and the CO2 produced in the process is captured and stored, the final product is known as blue ammonia. Green ammonia is made from hydrogen that has been generated using electricity from renewable sources.

What makes ammonia so interesting for the energy industry is its composition. Since ammonia combines three hydrogen atoms with one nitrogen atom, it is the ideal medium for transporting hydrogen by ship. Using what is known as a “cracker”, the chemical elements of nitrogen and hydrogen are then separated again once they reach their destination and the hydrogen can be used as a fuel. Some gas turbines and ship engines can even burn ammonia directly to produce energy.

Green ammonia stores hydrogen and delivers clean energy

Green ammonia is just green hydrogen with nitrogen added to “package” it as ammonia. Green hydrogen is generated via electrolysis, by using electricity from wind and solar power to split water into oxygen and hydrogen. This means that renewable energy can be stored in the form of green hydrogen and used in other ways. In a next step, green ammonia can make it far easier to transport the green hydrogen. This characteristic holds enormous potential for a global green energy industry and for reducing greenhouse gas emissions. Ammonia as an energy carrier can be used as a fuel and to transport the very versatile green hydrogen. The different ways for storing and transporting renewable energy via chemical processes in the form of ammonia are also known as power-to-ammonia.

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Pivotal advantages compared to pure hydrogen

Green ammonia can play an important part in supplying Germany with green hydrogen. As a chemical base material, ammonia is a product that is traded widely across the globe via an existing infrastructure. Unlike hydrogen, ammonia can be stored in large metal containers with thin walls. Compared to potential alternatives, ammonia is the most cost-effective liquid hydrogen carrier for longer-term storage and maritime transport. The key advantage compared to hydrogen is the considerably higher energy density of liquid ammonia, meaning it requires less storage space. Furthermore, ammonia can be used as a marine fuel.

RWE expects green ammonia to be able to replace grey ammonia in the long term. Experience shows that demand will increase in particular for existing processes that cannot be electrified, i.e. run with green electricity, meaning that companies need green-gas alternatives. New areas of application for green ammonia could include its use as a marine fuel and as a co-fuel in coal-fired power plants, for example in Japan and South Korea.

RWE and its partners invest in production and transport of ammonia

In order to achieve climate targets and in particular to decarbonise industry, the use of green molecules – as liquid hydrogen or ammonia – will become increasingly important. RWE has already started to develop a globally diversified portfolio of projects and purchase agreements for hydrogen and its derivatives. One of the lighthouse projects in this context is the import terminal for green ammonia at the Elbehafen port in Brunsbüttel, where up to 300,000 tonnes of green ammonia per year are to be landed from 2026.

This could be sourced, for example, from Namibia. To this end, RWE signed a memorandum of understanding with Hyphen Hydrogen Energy on the purchase of up to 300,000 tonnes of green ammonia per year. Another partnership of RWE with LOTTE Chemical and Mitsubishi is aimed at building up a joint infrastructure and the production of ammonia. The signatories are looking into building a large production facility for up to 10 million tonnes of ammonia in Texas. RWE is evaluating the possibility of transporting the gas within Germany via the rail network – in collaboration with Europe's leading private rail logistics company VTG, RWE is developing potential transport concepts.

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