Using ammonia to push hydrogen as an alternative fuel

Hydrogen, the simplest and most abundant element, could be the best renewable energy source to fuel vehicles of the future. Dr. XiaoYu Wu, a mechanical and mechatronics engineering professor at the University of Waterloo, certainly believes so — and he is not alone.

The worldwide demand for hydrogen is growing exponentially, notably for its ability to power vehicles without releasing harmful emissions. Global leaders and industry, particularly in the transportation sector, see the value of the gas as an alternative fuel to help our world decarbonize and reach net zero emissions.

The challenge is that hydrogen is light — it needs to be compressed at high pressure or turned into liquid to store it for transportation. Traditional methods are energy intense and costly. Wu and his team of graduate and post-doctoral students are working to solve this issue with their research into the potential of ammonia as a safe and efficient storage cell for hydrogen transportation.

“Currently, hydrogen production is energy intense. And scaling its development, distribution and storage infrastructure is costly,” says Wu.

“Using ammonia as a hydrogen carrier offers a much safer and more cost-effective approach that will help realize the potential of hydrogen as an alternative fuel source and thus, reduce the carbon footprint,” he continues.

Not only does ammonia store and transport hydrogen energy efficiently, but it is also cheap to produce, store and deliver, making it widely available. Ammonia is the second most traded chemical in the world with global annual production reaching over 230 million tonnes. Currently, the agricultural industry uses 80 per cent of this colorless, low carbon gas for fertilizer.

Canada’s federal government acknowledges hydrogen’s potential as an alternative fuel. As one of the top 10 hydrogen producers in the world, Canada entered into a ‘hydrogen alliance’ with Germany in 2022 to export its abundant supply of the gas to Europe. The government’s Hydrogen Strategy for Canada sets out objectives and strategies that illustrate how hydrogen can help Canada achieve its net zero goal by 2050 while concurrently growing the economy and creating jobs.

“We are working with the National Research Council Canada and Germany’s RWTH Aachen University to explore how ammonia and other types of hydrogen carriers can play an important role in exporting clean Canadian hydrogen to Germany,” says Wu.   

Wu recently received $250,000 in federal funding for a project he is leading that investigates ammonia as an energy “currency” to connect the food, energy and trade sectors. Wu enjoys making these connections — whether it’s collaborating locally with the City of Kitchener to look at how they could use hydrogen to decarbonize its transportation fleet or working with other countries and universities.

“Academics cannot work in silos,” says Wu. “That’s why it’s interesting to study something that has multiple applications. I’m really interested in how these different sectors can work together, how we can involve the economists, politicians and industry to understand what tools, policies and taxes we need implemented to increase the benefits of these alternative fuel sources, while concurrently understanding what new technology solutions we must develop in our labs.”

Dr. XiaoYu Wu and PhD student Jinhe Zhang looking at a ceramic proton conducting membrane fabricated in Wu's lab. Ammonia is a hydrogen carrier plus it has hydrogen stored in its molecules. When we need hydrogen, we have to extract hydrogen from ammonia by decomposing ammonia. The membrane allows only hydrogen to permeate — thus it is used to produce high-purity hydrogen by separating it from ammonia decomposition products. 

In between teaching, lab work and marking midterms, Wu is buried in research, along with his students, who are all focused on alternative fuel uses. Beyond ground transportation, the potential uses for hydrogen and ammonia as a fuel carrier are endless.

Wu is also involved with the University’s Waterloo Institute of Sustainable Aeronautics (WISA) — a global hub for sustainable aviation and aerospace research, technology, and education — studying the uses of these alternative fuels to potentially decarbonize the aviation and aerospace industries. 

“There’s no shortage of work,” he concludes. “What I love the most about being a researcher is that we get to look at different aspects of the problem while learning from and collaborating with others. As a professor, I also get to train students who graduate and use their knowledge to become industry leaders.

“There are lots of companies looking for people with this expertise,” he adds. “Students in my group come from different academic fields in mechanical and chemical engineering, mathematics and economics. This interdisciplinary expertise puts my research group in a unique position to tackle complex energy problems.

“It’s very rewarding to see my students take what they learn here and apply it in the industry or in the continuation of their research.” 

Learn more about Dr. XiaoYu Wu and his team’s work with the Greener Production Group. This editorial in the open access journal Frontiers in Energy Research, where he serves as a guest associate editor, also offers additional background.  

Interested in research studies at the University of Waterloo? Discover more about our Master of Applied Science (MASc) and Doctor of Philosophy (PhD) in Engineering degrees. 

Feature image: Dr. XiaoYu Wu (back row, second from right) with his research team in the lab. Photo by Martin Schwalbe.