Written by Alex Johnson. Photography by Fiona Wolf, Merri-May Gill and Colin Lenton.

But according to Professor PJ Cullen of the University of Sydney’s School of Chemical and Biomolecular Engineering, it’s a global problem in food production.

“We find that farmers in different countries, with very different crops, and operating at vastly different scales, all have a similar problem,” he says. “They would all like greater security in terms of the supply and cost of nitrogen-based fertiliser.”

For more than a century, the world's nitrogen-based fertilisers have used something known as the Haber-Bosch production process, which relies on cheap sources of hydrogen found in fossil fuels. This has concentrated fertiliser production in places that already have a significant fossil-fuel export industry.

“It’s carbon- and energy-intensive, leading to a highly centralised process carried out in a relatively small number of facilities worldwide,” PJ explains.

PJ is the co-founder and Chief Scientific Officer of PlasmaLeap Technologies, a University of Sydney spin-out committed to building accessible, sustainable technology for fuel and chemical production.  The solution, he says, lies in localised production technology using plasma technology. 

“Plasma is the fourth state of matter”, explains PJ. “Which is a nice way of saying it’s an excited gas.”

PlasmaLeap’s technology uses electricity to ‘excite’ the air in order to extract the nitrogen and convert it into useable products, including nitrates and ammonia.

As PJ points out, this isn’t a new concept. At the turn of century, production processes were more diversified as people explored various means of improving efficiency and cost-effectiveness, but certain processes fell by the wayside. 

“There used to be a plasma process completely driven by electricity, that was run off Niagara Falls,” he says. “It lost out, because it just wasn’t energy-efficient at the time.”

Thanks to advancements in electrical technology over the past century, innovations such as  PlasmaLeap’s eNfix units are now within reach. These small, modular units produce nitrogen-based fertiliser using only water, air and electricity – which can be generated from renewable sources such as solar power. 

In addition, the units can be installed directly on farms or at regional hubs, reducing the carbon footprint of both the fertiliser production process and the supply chains that deliver it.

“When we started to design and build this technology, we really pushed for the sustainability aspect,” PJ recalls. “But perhaps the biggest impact for farmers is turning out to be supply security.”

PJ and PlasmaLeap are now preparing to field-test prototypes on farms over the coming months, with commercial sales expected to begin in early 2027. 

It’s exciting news for Scott, who recently successfully tested the technology on his sorghum crop. “This is a potential game changer and will futureproof Australia’s food supply system,” he says.  “It’s Australian technology, built for our conditions, producing fertiliser in our regions. It’s something that works right here in the paddock.” 

While Scott’s transition to more secure energy on the farm is well underway, the energy fuelling the global supply chain is facing other challenges. Many of Australia’s everyday consumer items – from cars and electronics to food, are imported from international suppliers – representing around $658 billion in 2025. Moving these goods relies heavily on existing fuel sources and freight networks that remain vulnerable to market disruptions. 

Alumnus Gregory Constantine (BA (Media&Comm ’13), co-founder of Air Company Holdings (AIRCO), doesn’t shy away from that conversation.

For the former music student and marketer, founding a climate tech start-up wasn’t part of his original career plan, but he’s also not completely surprised to find himself in this space.

“I always knew I wanted to do things that were challenging,” he says. “Starting this business was the most challenging thing I could think of. That’s what excited me about it.”

Gregory’s idea was simple enough: what if carbon dioxide could be treated as a resource rather than a waste product? Today, AIRCO's technology converts carbon dioxide and hydrogen into fuels and chemicals, helping to create lower-emissions fuels for aviation, shipping, defence and other industries where reducing carbon emissions remains particularly challenging.

He likens AIRCO’s process to the way plants use CO2, water and sunlight and turn it into energy. 

“We’re really just taking a page out of nature’s book and trying to make it more efficient, essentially,” he says.  

Unlike many other clean energy solutions, AIRCO's synthetic fuels are compatible with existing engines, pipelines and logistics infrastructure, avoiding the disruption and cost of a complete system overhaul.

“The benefits are massive – not just for decarbonisation, but also from a decentralisation point of view,” Gregory explains. “AIRCO's technology decentralizes fuel and chemical production so you can produce it locally where it’s needed most, reducing reliance on centralized infrastructure and fragile global supply chains.”

But while the technology exists, the challenges of scale and cost remain. 

“It’s not a magic formula,” Gregory says. “You need large amounts of clean electricity to be cheap enough and abundant enough to matter.”

Beyond environmental considerations, Gregory says the unfolding energy crisis has highlighted the need for Australia to become more energy independent.

“The question isn’t whether we can build interesting technology,” he says. “It’s whether we can build technology that matters to the world – and that’s for industry and climate and energy resiliency – and for national resilience, at the end of it all.”

Ultimately, the collective long-term vision is an Australian energy system that relies less on centralised infrastructure and global supply chains, and more on local production. 

“With supply security, you can have price security,” PJ explains. “Therefore, you can prevent against shocks to the supply, which are ultimately, represented as shocks in terms of price.”

In other words, more stable energy prices could deliver more price stability for consumers at the checkout.

Although their technologies operate in very different sectors and at vastly different scales, PJ and Gregory are both working towards a future in which essential resources can be produced more sustainably, more reliably, and closer to home. 

As Australia’s energy systems continue to evolve, the focus is now on more than simply lowering emissions. It’s on improving long-term resilience for Australian households, industries and communities.

Hero image: Scott McCalman's farm at Gunedah. Photo: Merri-May Gill/ The University of Sydney.