‘Lightning’ in a bottle could extract nitrogen from the air, delivering green ammonia to farmers

After a thunderstorm, you may have noticed plants become greener and lusher, more so than after an average rainy day.

This is because lightning has the ability to “fix” nitrogen in the air and make it available to plants.

A trial at a vineyard near Auburn in South Australia attempted to replicate this process, effectively creating “eclair in a bottle”.

The work grew out of the development of a technology called a non-thermal plasma unit which effectively acts as a controlled flash or arc welder.

Research scientist Greg Butler is fielding and testing the technology, to see if it can effectively replicate the natural nitrate creation process found in thunderstorms.

To do this, he set up a system where air is forced into a container of water using an air compressor.

A non-thermal plasma unit.(Rural ABC: Cassandra Hough)

Since nitrogen makes up about 78% of the atmosphere, air becomes the source of nitrogen.

“If you imagine having an arc welder in a beaker of water and then blowing air past it, that effectively mimics lightning in a very controlled way,” he said.

The unit breaks down the molecular forms of nitrogen and oxygen in the air and they are reformed as nitric oxide and dissolved in water.

“From there, we harvest that nitrogen into a liquid, and then our goal is to push it through the fertigation system,” Butler said.

Fertigation is the process of adding dissolved fertilizer to crops through an irrigation system.

Liquid fertilizer for farmers

Michael Paxton is the Vineyard Manager for Randall Wine Group in Clare, where the trial is taking place.

The property already has a fertigation system, so he was keen to try the technology.

“Traditionally, fertigation is the most effective fertilizer, especially [for getting] nitrogen to the roots – so we’ve rehearsed some of it well,” Paxton said.

“This technology, pulling it out of thin air, seems like a fantastic opportunity.”

drip irrigation
Fertigation delivers dissolved fertilizers to crops through an irrigation system.(ABC News)

Mr Paxton was attracted to the idea because he believed it offered environmental and financial benefits.

“The machine will run off solar panels, so it will be relatively cheap…compared to buying nitrogen,” he said.

“As all farmers know, urea is extremely expensive, so I think it will be a very good option.”

The Haber-Bosch process for producing conventional nitrogen fertilizer by mixing nitrogen from the air with hydrogen gas at high pressure to create ammonia was developed about 120 years ago.

Mr Butler said it was a very energy-intensive process, so if this new system could be powered by solar electricity, it could eliminate the embodied energy in nitrogen production.

“Also, because it’s produced locally, there are far fewer transportation emissions associated with that nitrogen,” Butler said.

The project is one of the recipients of the first round of Federal Government Supply Chain Resilience Grants and received $232,000 in matching funding.

Mr Butler said he would be commissioning and testing the technology over the next few months.

“So what that really means is refining it, starting to understand recycling and concentrating, pumping it into the fertigation system [and] do some simple trials on relatively small blocks,” he said.

“And from there we look at scale and additional efficiency.”

Robert M. Larson