Dr Joseph Mooney — Sir Bernard Crossland award winner, Trinity College Dublin alumnus and former postdoctoral researcher whose work spans advanced engineering research, climate and energy innovation, and technology commercialisation — has recently been recognised in the prestigious Forbes '30 under 30' list.

Dr Mooney was recently named to the Forbes 30 Under 30 list for 2026 in the Energy and Green Tech category, recognising his contribution to climate and sustainability focused engineering and entrepreneurship. The recognition highlights emerging leaders whose work is shaping the future of global energy and environmental systems.

Dr Mooney previously held a postdoctoral position at Trinity College Dublin School of Engineering, where he worked with Professors Robinson, O'Shaughnessy, Pakdel, Persoons, Gibbons and Lupoi and Huawei Technologies Sweden AB on the thermal management of 5G wireless infrastructure. This research addressed one of the key technical challenges facing next generation communications networks, improving performance, efficiency, and sustainability.

Dr Joseph Mooney.

He is also a Trinity alumnus, having completed an MSc in Innovation and Entrepreneurship at Trinity Business School. This combination of deep technical expertise and entrepreneurial training has played a central role in shaping his career, particularly his focus on translating research into real world impact.

Currently, Dr Mooney is a research engineer at the Georgia Institute of Technology and co-founder and CEO of WattAir, a company co-founded with Professor Bachir El Fil, a professor of mechanical engineering at Georgia Tech.

WattAir is focused on commercialising water and energy technologies with global impact. His research and innovation interests span data centre thermal management, building cooling, water harvesting, and the green energy transition. WattAir builds directly on Dr Mooney’s academic training in thermal-fluid sciences and systems engineering, reflecting Trinity’s emphasis on research that delivers tangible societal and environmental benefit.

Dr Mooney says water scarcity and access to clean water are emerging as binding constraints on economic growth and infrastructure resilience worldwide, with nearly two billion people lacking access to safe drinking water and global water demand projected to exceed supply by ~40% by 2030.

At the same time, energy-intensive infrastructure is expanding rapidly in high-GDP economies; in Ireland, data centres already account for ~21% of national electricity consumption, a figure projected to rise significantly as digital services and AI workloads grow. These facilities also generate large quantities of low-grade waste heat and consume substantial volumes of water for cooling, placing additional pressure on both electrical grids and municipal water systems.

Using waste heat to extract water directly from ambient air

Atmospheric water harvesting presents an opportunity to address this coupled challenge by using waste heat to extract water directly from ambient air, transforming an otherwise discarded energy stream into a valuable local resource while improving overall system efficiency and reducing strain on water and power infrastructure.

Water scarcity as a function of a country's GDP.

WattAir is developing water-from-air and cooling technologies that reuse low-grade waste heat from data centres to produce clean water, turning a thermal by-product into a valuable resource. Data centres already account for over 20% of Ireland’s electricity demand, and many facilities rely on significant volumes of water for cooling and humidity control.

By harvesting water directly from the air using waste heat, WattAir’s approach can reduce both electrical cooling loads and dependence on municipal water supplies. This integrated solution supports more sustainable data-centre growth while easing strain on Ireland’s power and water infrastructure.

Dr Mooney’s career includes a series of prestigious international fellowships and awards. He is a former MIT Postdoctoral Research Fellow, a Marie Skłodowska-Curie Postdoctoral Fellow with the European Commission, and a recipient of a Breakthrough Energy Explorer Grant. He completed his PhD through CONNECT and Nokia Bell Labs, focusing on the thermal management of 5G WiFi technologies.

Alongside his research and entrepreneurial work, Dr Mooney is deeply engaged in mentorship, collaboration, and professional service. He was an advisor to MIT and Harvard Climate and Energy Ventures, a Science Foundation Ireland CONNECT Centre Affiliate Investigator, a member of Engineers Ireland, and a mentor and advisor across multiple Georgia Tech & MIT research and undergraduate programmes.

Excellence in research communication

He has supervised students at undergraduate and postgraduate level and has been recognised for excellence in research communication, including receiving the ASME IMECE Best Presentation Award and the Sir Bernard Crossland Symposium best presentation award.

TCD said: "The School of Engineering congratulates Dr Joseph Mooney on his Forbes 30 Under 30 recognition and his continued impact across engineering, climate innovation, and entrepreneurship. His career reflects the strength of Trinity’s research culture and the value of interdisciplinary education in addressing global challenges."

The Forbes annual rank­ings, which spot­light 600 young lead­ers across 20 indus­tries, are regarded as one of the most influ­en­tial baro­met­ers of emer­ging global tal­ent, and Dr Mooney’s inclu­sion places him among a select group shap­ing the future of energy, sus­tain­ab­il­ity and infra­struc­ture.

For Dr Mooney, aged 28, the recog­ni­tion is not framed as a per­sonal mile­stone so much as a val­id­a­tion of the prob­lem he and his com­pany are try­ing to solve, he told the Sligo Weekender.

As founder and chief exec­ut­ive of WattAir, a green tech­no­logy star­tup estab­lished in 2025, he is focused on one of the most press­ing and inter­con­nec­ted chal­lenges facing the world: the grow­ing strain on water and energy sys­tems.

WattAir is build­ing tech­no­logy that har­vests water dir­ectly from the atmo­sphere while sim­ul­tan­eously improv­ing energy effi­ciency, a dual approach that reflects Mooney’s belief that water scarcity and energy inef­fi­ciency can­not be addressed in isol­a­tion.

In a year that saw more than 10,000 nom­in­a­tions con­sidered by For­bes, the judging panel included high-pro­file fig­ures such as pop star Olivia Rodrigo, act­ress and act­iv­ist Yara Shahidi, and bil­lion­aire entre­pren­eur Palmer Luckey. Against that com­pet­it­ive back­drop, Mooney’s inclu­sion in the energy and green tech cat­egory stands out not only because of his age, but because of the ambi­tion and clar­ity of WattAir’s mis­sion.

“More than any­thing, I see this as a sig­nal of belief in the prob­lem we’re work­ing on – mak­ing sus­tain­able water and cool­ing a real­ity for people and indus­tries under stress – rather than a per­sonal achieve­ment,” he said in a state­ment fol­low­ing the announce­ment.

Developed an early interest in engin­eer­ing and prob­lem-solv­ing

Dr Mooney’s jour­ney to this point began far from the ven­ture cap­ital cor­ridors of North Amer­ica. Grow­ing up in Drum­cliffe, Co Sligo, he developed an early interest in engin­eer­ing and prob­lem-solv­ing, interests that would later shape an aca­demic and pro­fes­sional path rooted in sci­ence and applied research.

Now a research engin­eer at the Geor­gia Insti­tute of Tech­no­logy, one of the world’s lead­ing engin­eer­ing schools, Dr Mooney has immersed him­self in mater­i­als sci­ence, ther­mo­dy­nam­ics and energy sys­tems, dis­cip­lines that under­pin WattAir’s core tech­no­logy.

At the heart of WattAir’s innov­a­tion is a pro­cess that uses hydro­gel-coated heat exchangers to cap­ture mois­ture from the air. While atmo­spheric water har­vest­ing is not a new concept, WattAir’s approach is designed to be far more energy-effi­cient and scal­able than exist­ing sys­tems.

By care­fully con­trolling how heat, air and mois­ture inter­act, the tech­no­logy can draw water from even rel­at­ively dry air while mak­ing use of low-grade or waste heat that would oth­er­wise be lost. The res­ult is a decent­ral­ised sys­tem cap­able of pro­du­cing water while redu­cing over­all energy con­sump­tion.

Targeting sec­tors where water and energy demands col­lide most sharply

The poten­tial applic­a­tions are wide-ran­ging. WattAir is tar­get­ing sec­tors where water and energy demands col­lide most sharply, includ­ing agri­cul­ture, HVAC sys­tems, data centres and off-grid install­a­tions. In agri­cul­ture, access to reli­able water sup­plies is increas­ingly uncer­tain due to cli­mate change, while energy costs con­tinue to rise.

In data centres, which under­pin the digital eco­nomy, enorm­ous amounts of energy are expen­ded on cool­ing, often in regions already facing water stress. By integ­rat­ing water har­vest­ing with cool­ing and heat recov­ery, WattAir aims to turn inef­fi­ciency into resi­li­ence.

The com­pany has already secured $300,000 in ini­tial fund­ing, an early vote of con­fid­ence from investors in both the tech­no­logy and the vis­ion behind it.

That vis­ion is groun­ded in a simple but power­ful idea: that every joule of energy and every drop of water should serve more than one pur­pose. WattAir’s philo­sophy is that the tra­di­tional sep­ar­a­tion of water and energy sys­tems has led to waste on both fronts, and that smarter, more integ­rated design can unlock sig­ni­fic­ant gains.

Reima­gin­ing infra­struc­ture

This sys­tems-level think­ing is a recur­ring theme in Dr Mooney’s work. Rather than chas­ing incre­mental improve­ments, he has con­sist­ently argued for reima­gin­ing infra­struc­ture in a way that reflects the real­it­ies of a warm­ing world and a grow­ing global pop­u­la­tion.

His com­pany’s tech­no­lo­gies are designed to be com­pact, mod­u­lar and adapt­able, cap­able of being deployed where they are most needed rather than rely­ing on large, cent­ral­ised net­works that are vul­ner­able to dis­rup­tion.

Dr Mooney is one of sev­eral Irish innov­at­ors recog­nised on this year’s North Amer­ica list, under­lin­ing the depth of Irish tal­ent mak­ing an impact on the global stage.

Among the oth­ers are Jamie Palmer, co-founder and chief tech­no­logy officer of Icarus Robot­ics, and the Irish co-founders of Ulysses, a San Fran­cisco-based star­tup build­ing autonom­ous ocean vehicles. But while those com­pan­ies are work­ing on chal­lenges ran­ging from space robot­ics to mari­time secur­ity, Dr Mooney’s focus on water and energy places him squarely at the centre of debates about sus­tain­ab­il­ity and cli­mate resi­li­ence.

What sets WattAir apart is not just its tech­nical approach, but its emphasis on prac­tic­al­ity and deploy­ment. The com­pany’s stated aim is to enable farms, indus­tries and com­munit­ies to pro­duce their own water and cool­ing using energy that is already avail­able, whether from sun­light, ambi­ent air or waste heat.

In doing so, it seeks to reduce depend­ence on over­stretched grids and fra­gile sup­ply chains, offer­ing a meas­ure of autonomy in an increas­ingly uncer­tain world.

Identi­fy­ing indi­vidu­als who go on to shape indus­tries and influ­ence policy

For­bes’ '30 Under 30' list has a track record of identi­fy­ing indi­vidu­als who go on to shape indus­tries and influ­ence policy, and inclu­sion often brings increased scru­tiny as well as oppor­tun­ity.

For Dr Mooney, that atten­tion is wel­come if it helps accel­er­ate pro­gress on the under­ly­ing prob­lem.

His response to the hon­our reflects a broader mind­set com­mon among cli­mate-focused entre­pren­eurs, one that pri­or­it­ises impact over pro­file and col­lab­or­a­tion over com­pet­i­tion.

As water scarcity and energy effi­ciency move ever higher up the inter­na­tional agenda, the work being done at WattAir sug­gests that some of the most import­ant solu­tions may come not from massive infra­struc­ture projects, but from smarter, more integ­rated sys­tems designed by people will­ing to rethink the fun­da­ment­als. In that con­text, Dr Mooney’s inclu­sion on the For­bes list is less an end­point than an early marker of a career focused on turn­ing sci­entific insight into real­-world resi­li­ence.