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ENERGY: The hydrogen economy is approaching at gathering pace, but safe and compact storage of hydrogen is problematic. A research team at the Technical University of Denmark (DTU) has taken out a patent on a method of hydrogen storage, which involves ammonia bound in a solid state, as a safe carrier and storage medium for the far more unmanageable and dangerous hydrogen.

Tue Johannesen, Amminex A/S

The method takes a step closer to a technical solution of one of the most important problems in realising the hydrogen society. It has also created the basis for starting up a new high tech Danish company.

Co-inventor Tue Johannesen explains: “Hydrogen molecules are difficult to handle, and hydrogen mixed with air can be highly explosive. Ammonia as a hydrogen carrier is easier to transport, but ammonia in fluid form is not that safe for ordinary users either, and in large concentrations is very toxic. We have developed a method which combines the attractive properties of ammonia with high safety. By absorbing ammonia in a solid substance, the material becomes as non-hazardous as an ordinary window cleaning agent. When the substance is heated, the ammonia is released and can be used for fuel directly in a high temperature fuel cell or split into free non-hazardous nitrogen and hydrogen which can be fed into an ordinary fuel cell”.

International interest
“There is great international interest in our product”, says Tue Johannesen, who currently has a leave of absence from his position as senior lecturer at DTU’s Department for Chemical Engineering, to be director of start-up company Amminex A/S.

“We are receiving approaches from many parts of the world, and we are currently spending a lot of time screening the contacts and considering the most interesting ones. We are also engaged in a round of financing, and we are increasing our staff so that an optimised prototype can be developed rapidly. When that has happened, we will develop, in collaboration with manufacturers of fuel cells, the adaptations which best suit the various units which will use our hydrogen energy”.

Simple and cheap
“Regarding our technology, these are primarily units which today are powered by lead-acid batteries, and where typically three batteries are cycled constantly – one in use, one on charge and one cooling down. The most obvious applications are forklift trucks, golf carts and electric wheelchairs. A fuel cell powered forklift truck which runs on compressed hydrogen, uses 2.8 kilos hydrogen per day, which is stored at a pressure of 200 bar in four 50 litre steel containers. This can be replaced by just 40 kilos of hydrogen pellets in the form of one or several hydrogen rods.”

But the hydrogen society is not just around the corner. A careful estimate gives a 20 year time horizon before this form of energy feeds through. “There is still no cheaper energy source than crude oil or coal”, emphasis Tue Johannesen, “but it is necessary to think along new lines.”

Commercial breakthrough
Amminex A/S, which holds the rights to the hydrogen pellet, has three shareholders: The inventors, DTU and Seed Capital Denmark. The firm hopes to make a serious breakthrough in 3-5 years, when the most obvious prototypes have been developed, tested and marketed. “But forget everything about pellets in the petrol tank for some time to come, a picture which otherwise is often associated with cars and hydrogen energy”, says Tue Johannesen. “For one thing there will never be many small pellets. For another a lot of other factors must fall into place, before hydrogen energy can be used as the energy carrier on the car market.” 


This page forms part of the publication 'FOCUS DENMARK' as chapter 12 of 21

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