About 80 percent of produced ammonia is used in agriculture as fertilizer. It’s had a huge impact on us since the start of the 20th century, yet it leaves a massive carbon footprint.
To try and combat this issue, chemical engineers from the University of New South Wales (UNSW) and the University of Sydney in Australia have found a way to make ammonia 100% renewable.
Their research has so far only been tried and tested in a lab environment, but it has the potential to shift the industry towards a greener, hydrogen economy.
The study was published in Energy & Environmental Science.
The use of ammonia in fertilizers has quadrupled the output of food crops globally, assisting agriculture to keep up with our ever-expanding population’s needs.
However, when produced on a large scale in the traditional method — the Haber-Bosch process —, ammonia requires a lot of energy from heat, leading to the use of fossil fuels.
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“The current way we make ammonia via the Haber-Bosch method produces more CO2 than any other chemical-making reaction,” said Dr. Emma Lovell, co-author of the paper and from the UNSW School of Chemical Engineering.
“In fact, making ammonia consumes about 2 percent of the world’s energy and makes 1 percent of its CO2 – which is a huge amount if you think of all the industrial processes that occur around the globe.”
On top of that, as Dr. Lovell pointed out, as it has to be produced en masse it requires centralized locations to do so, which then increases transportation requirements — further exacerbating the carbon emissions issue. Large masses of ammonia need to be stored as well, which can sometimes lead to dangerous outcomes, like the tragic explosion in Beirut last year.
How the team created renewable, safer ammonia
The team found a way of producing 100 percent renewable ammonia that can be made on site. It doesn’t require any fossil fuel resources and doesn’t emit CO2. “So if we can make it locally to use locally, and make it as we need it, then there’s a huge benefit to society as well as the health of the planet,” said Dr. Lovell.
The key ingredient to the team’s method was plasma.
Professor Patrick Cullen, who led the University of Sydney team, said “Atmospheric plasma is increasingly finding application in green chemistry. By inducing the plasma discharges inside water bubbles, we have developed a means of overcoming the challenges of energy efficiency and process scaling, moving the technology closer to industrial adoption.”
In creating their “green” method of producing ammonia, the team also solved the issue of storage and transportation of hydrogen energy.
As Scientia Professor Rose Amal, who is co-director of ARC Training Centre for Global Hydrogen Economy, said “We can use electrons from solar farms to make ammonia and then export our sunshine as ammonia rather than hydrogen.”
“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,” she added.
The next steps for the team are to turn its efforts to commercialize its product.