Innovative ideas can come from anywhere, but the strongest solutions are often grounded in real-world challenges. That is the case for Daniel Cox, whose solar-powered approach to aquatic weed control has earned him the 2026 Australian Stockholm Junior Water Prize (sponsored by Xylem) at the Australian Water Awards in May.
The 16-year-old Scots College student was recognised for SunRay Aqua, an innovative solar-thermal system that uses a distributed array of mirrors and a drone-mounted receiver to deliver targeted heat treatment to invasive aquatic weeds without chemicals.
The project was recognised for its exceptional innovation, scientific rigour, technical depth and real-world applicability.
Daniel will now represent Australia at the International Stockholm Junior Water Prize during World Water Week (23-27 August), joining students from around the world to showcase emerging solutions to global water challenges.
Voting is now open for the Stockholm Junior Water Prize People's Choice Award, giving the water community the chance to support the recognition of this outstanding young water innovator. Support Daniel by casting your vote here.
Daniel's interest in weed control stretches back long before he began designing prototypes or writing algorithms.
"On my dad's side, I come from generations of Australian farmers. So weeds, and just how hard they are to control, have always been part of my world," he said.
"Growing up around that, you absorb the fact that weed control is relentless, expensive, and never really done. It was a problem I understood long before I ever thought of myself as someone who might solve it."
Daniel with his father on their family farm.
Daniel said the idea that ultimately became SunRay Aqua came from an everyday observation.
"The spark was almost embarrassingly simple. Everyone knows the trick of using a magnifying glass to focus sunlight into a single hot point, and I started wondering whether that same principle, concentrating light to destroy a weed, could be scaled into something useful," he said.
As Daniel explored the concept, he found existing solar concentration technologies all faced the same limitation. While capable of generating intense heat, they treated only a very small area and required an impractical level of precision for real-world conditions.
Instead, he looked to solar power towers, where large fields of mirrors concentrate sunlight to generate extreme temperatures.
"That was the moment it clicked: if you can reach those temperatures just by aiming sunlight cleverly, why couldn't the same principle be turned on a weed? So the question became, could I adapt the solar power tower concept into a weed-control system?"
After developing a land-based version, Daniel began considering how the technology could be adapted for waterways.
"Aquatic weeds stood out immediately. Although herbicides can be used in waterways, they risk affecting water quality and non-target organisms. A light-focusing approach avoids introducing chemicals into the water, killing the weeds through heat instead," he said.
The result was SunRay Aqua, which combines drone and pontoon platforms to apply concentrated solar energy to invasive weeds while avoiding chemical inputs.
For Daniel, the move into aquatic environments also carried a personal significance: "This innovation is close to my heart because of its connection to water."
"Developing SunRay Aqua allowed me to bring together my farming background, my environmental concerns, and my belief that engineering should help protect the resources on which communities depend," he said.
Daniel's commitment to water extends well beyond the laboratory. In 2023, he founded Green Kites International Association, a youth-led organisation delivering water, sanitation and hygiene (WASH) projects for underserved communities in Vietnam.
Since 2024, Daniel has spent his school holidays leading volunteer teams to install rainwater harvesting and water filtration systems at eight schools across three provinces. Alongside improving access to clean water, the projects also deliver WASH education to help students build healthy hygiene practices and make the most of the new infrastructure.
The work has also created plenty of memorable moments. At several schools, Daniel has become affectionately known as "the toilet guy" after installing systems that provide flushing water for school toilets.
To help fund future projects, Daniel also held a photography exhibition in Ho Chi Minh City, with proceeds supporting additional water initiatives and allowing the program to reach even more communities.
Turning the SunRay Aqua concept into a working system required much more than a good idea. Initially, Daniel believed the greatest challenge would be developing the software needed to aim the mirrors accurately. Instead, the most difficult problem proved to be establishing an accurate reference frame for each heliostat.
"For all the calculations to work they have to be relative to an exact orientation," he explained. After exploring several unsuccessful approaches, including manual calibration and precise physical alignment, he eventually found a solution in an unexpected place.
"I searched widely online for a solution and eventually found the rotation matrix method developed, interestingly, for satellite navigation, which allowed for a rapid setup without requiring exact orientation," he said.
While SunRay Aqua offers clear environmental benefits, Daniel believes sustainability alone is not enough to drive adoption. Instead, the project's greatest strength lies in bringing environmental and operational outcomes together.
"The overarching aim of the system was to control weeds using little more than power from the sun, keeping operating costs as low as possible," he said.
"The absence of herbicide is really a side effect of this cost goal: a system that relies on focused sunlight to do its work doesn't need chemicals to be bought, transported, or applied, so that whole category of cost and complexity falls away."
The resulting system offers a range of potential benefits, from eliminating chemical handling and reducing contamination risks to avoiding herbicide resistance and lowering ongoing operating costs.
"In aquatic environments especially, avoiding contamination isn't a minor benefit but could be the deciding factor in whether a treatment is workable at all," he said.
"In the end, the low-cost system and the environmentally friendly system turned out to be the same system. Keeping operating costs down and keeping environmental impact down came from the same approach, and that is what makes it compelling."
Daniel at his photography exhibition in Ho Chi Minh City,
raising funds to support future water projects.
Winning the Australian Stockholm Junior Water Prize marks an important milestone, but Daniel sees it as the beginning of the project's journey rather than its conclusion.
His next priority is to undertake larger field trials across different aquatic weed species and environmental conditions, while continuing to refine the system's tracking capabilities, treatment efficiency and overall cost-effectiveness.
Ultimately, he hopes to see SunRay Aqua used in environmentally sensitive waterways where conventional chemical treatment may not be appropriate, before expanding its application to sun-rich regions where affordable, renewable technologies could have the greatest impact.
Before then, Daniel will take Australia's innovation to Stockholm, where he is looking forward to exchanging ideas with fellow young innovators from around the world.
"I am incredibly honoured to represent Australia at the International Stockholm Junior Water Prize," he said.
"What I am most looking forward to is meeting other young people who are tackling water challenges in completely different environments and learning how their experiences have shaped their solutions.
"I am also excited to present SunRay Aqua to international water experts and receive valuable feedback that could help me improve both the technology and its potential real-world applications.
"World Water Week brings together researchers, engineers, policymakers and communities, so it is a rare opportunity to understand water problems from perspectives far beyond my own."
The Australian Water Association congratulates Daniel on his achievement and wishes him every success as he represents Australia on the international stage. His work demonstrates the ingenuity, curiosity and commitment that continue to shape the future of water and highlights the important contribution young innovators can make to addressing complex challenges.
Voting is now open for the Stockholm Junior Water Prize People's Choice Award. Help support Daniel by voting here.