Eco-friendly ammonia touted as key to hydrogen production and storage

Chemical engineers at UNSW Sydney have reportedly found a way to make ‘green’ ammonia from air, water and renewable electricity.

The new process is said to not require the high temperatures and pressures in addition to the huge infrastructure currently needed to produce this essential compound, and therefore has the potential to play a role in the global transition towards a hydrogen economy, where ammonia is increasingly seen as a solution to the problem of storing and transporting hydrogen energy.

The process has been documented in a paper authored by Scientists from UNSW and University of Sydney and published in Energy and Environmental Science.

Dr Emma Lovell, a co-author on the paper from UNSW’s School of Chemical Engineering, said the traditional way to make ammonia – known as the Haber-Bosch process – is only cost-effective when it’s done on a massive scale due to the huge amounts of energy and expensive materials required.

“The current way we make ammonia produces more Co2 than any other chemical-making reaction,” she said.

“In fact, making ammonia consumes about two per cent of the world’s energy and makes one per cent of its Co2,” said Lovell.

Lovell and her colleagues therefore looked at how to produce it cheaply, on a smaller scale and using renewable energy.

“The way that we did it does not rely on fossil fuel resources, nor emit Co2,” she said.

“And once it becomes commercially available, the technology could be used to produce ammonia directly on site and on demand – farmers could even do this on location using our technology to make fertiliser, thus negating the need for storage and transport.”

Further to this, Scientia Professor Rose Amal, who is Co-Director of ARC Training Centre for Global Hydrogen Economy, said in addition to the advantages of being able to scale down the technology, the team’s ‘green’ method of ammonia production could solve the problem of storage and transport of hydrogen energy.

“Hydrogen is very light, so you need a lot of space to store it, otherwise you have to compress and liquify it,” said Amal.

“But liquid ammonia actually stores more hydrogen than liquid hydrogen itself, so there has been increasing interest in the use of ammonia as a potential energy vector for a carbon-free economy.”

Amal said ammonia could potentially be made in large quantities for export using the new green method.

“We can use electrons from solar farms to make ammonia and then export our sunshine as ammonia rather than hydrogen,” she said.

“And when it gets to countries like Japan and Germany, they can either split the ammonia and convert it back into hydrogen and nitrogen, or they can use it as a fuel.”

The team will reportedly next turn its attention to commercialising this technological breakthrough, and said it is seeking to form a spin-off company to take its technology from laboratory-scale into the field.