It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Sunday, January 19, 2020
Hydrogen is blowing up: From science experiment to export industry
Remember those science experiment cars powered by water? That technology could help Australia decarbonize its economy and become a major player in a zero-emissions world.
Did you ever do the science experiment at school where you fueled little plastic cars with water?
Those neat little guys were a cool way to learn about electrolysis, the process of using electricity to split water into two gases: hydrogen and oxygen. These gases became the fuel, and zip! The car would move.
A fun science demonstration, sure. But what if this technology could be used to decarbonize the economy and establish a valuable export industry for Australia?
Key to unlocking the energy industry potential of liquid hydrogen is Steph Munro. She's a chemical engineering whiz and Visiting Student Researcher at UWA's Australian Centre for LNG Futures. Steph is part of a team working towards making hydrogen a viable energy source.
"In recent years, we've seen growing pressure to decarbonize the economy, and government is encouraging this," Steph says.
"Future energy use will come from greener sources, and hydrogen will potentially be a major player in this area."
So how does hydrogen work as a fuel?
Burn, baby!
When burned, hydrogen produces water and releases a lot of heat as energy. That makes it a great fuel with no carbon emissions. But how does the process work?
Until now, hydrogen has mainly been used for various industrial processes. But there's a significant opportunity for hydrogen to be used for electricity, transport, heat and more.
"Hydrogen has become a major player in this area. And that's because it's perfect for decarbonizing parts of the economy that are difficult to electrify," Steph says.
Take long-haul trucks, for example. Because they travel such vast distances, electric batteries aren't suitable. No battery can cover the distance required, and they take too long to recharge. But a hydrogen-fueled truck can be quickly refueled, just like a diesel-fueled truck.
So that little toy fuel cell car from science class? Imagine that, but a long-haul truck.
Going global
As the global demand for hydrogen grows, exporting hydrogen could be big for Australia.
Hydrogen and fuel cells explained. Credit: FuseSchool – Global Education
In 2030, the annual liquid hydrogen demand from China, Japan, South Korea and Singapore is likely to be 3.8 million tonnes, according to CSIRO. That could represent almost $10 billion a year for the Australian economy.
"There is an opportunity for Australia to export hydrogen to nations that don't have the renewable energy infrastructure to decarbonize their economy," Steph says.
So what are we waiting for?
The challenges
Like anything requiring new infrastructure, there are significant challenges to overcome.
"The main challenge with hydrogen is that it exists at atmospheric conditions as a gas, which takes up a large volume," Steph says. "That can be a problem if you want to import 900,000 tonnes as a fuel."
"This is why natural gas is exported as LNG or liquefied natural gas."
But that doesn't mean it's easy to liquefy hydrogen. In order to liquefy gases, you need to cool them to very cold temperatures.
"Natural gas liquefies at -161°C, but hydrogen gas liquefies at -253°C. That requires a lot of energy," Steph says.
It's so hard to cool things down that, in a tank of liquid hydrogen, more than one-third of the energy goes towards liquefying it.
"We're currently working on leveraging our knowledge in LNG to make liquefaction more energy efficient," Steph says.
"There are a number of conceptual models of liquefaction plants that are much more efficient. The next step is developing those conceptual plants into reality."
And lastly, liquid hydrogen is just a bit weird. "Because liquid hydrogen exists at such cold temperatures, we don't yet totally understand it. That makes ironing out inefficiencies quite difficult," Steph says.
"Due to these challenges, we're likely to see a hydrogen industry that embraces multiple technologies, not just liquid hydrogen."
The next steps
While there are challenges, bright minds are working on meeting them.
In the meantime, we'll be playing with our fuel-cell toys.
Illustration highlighting the association of hydrogen (red) with dislocations in the crystal structure of steel. Credit: University of Sydney
In a world first, University of Sydney researchers have found evidence of how hydrogen causes embrittlement of steels. When hydrogen moves into steel, it makes the metal become brittle, leading to catastrophic failures. This has been one of the major challenges in moving towards a greener, hydrogen-fuelled future, where steel tanks and pipelines are essential components that must be able to survive in pure hydrogen environments.
Published in Science, the researchers found hydrogen accumulates at microstructures called dislocations and at the boundaries between the individual crystals that make up the steel.
This accumulation weakens the steel along these features, leading to embrittlement.
The researchers also found the first direct evidence that clusters of niobium carbide within the steel trap hydrogen in such a way that it cannot readily move to the dislocations and crystal boundaries to cause embrittlement. This effect has the potential to be used to design steels that can resist embrittlement.
Lead researcher Dr. Yi-Sheng Chen from the Australian Centre for Microscopy and Microanalysis and Faculty of Engineering at the University of Sydney said these findings were an important step to finding a safe solution to produce, store and transport hydrogen.
"These findings are vital for designing embrittlement-resistant steel; the carbides offer a solution to ensuring high-strength steels are not prone to early fracture and reduced toughness in the presence of hydrogen," Dr. Chen said.
Atom probe Image showing accumulations of hydrogen (red) at carbon-rich (blue) dislocations in steel. This evidence underpins the theoretical prediction of the origin of hydrogen embrittlement that limits the progress of hydrogen economy. Credit: University of Sydney
Senior author Professor Julie Cairney from the Australian Centre for Microscopy and Microanalysis and Faculty of Engineering at the University of Sydney said these findings were a positive step towards implementing clean fuels.
"Hydrogen is a low carbon fuel source that could potentially replace fossil fuels. But there are challenges with the use of steel, the world's most important engineering material, to safely store and transport it. This research gives us key insights into how we might be able to improve this situation," Professor Cairney said.
Illustration highlighting the concentration of hydrogen atoms (red balls) at the crystal boundaries and dislocations in steel. Credit: University of Sydney
Working in partnership with CITIC Metal, the researchers were able to directly observe hydrogen at microstructures in steels thanks to Microscopy Australia's state-of-the-art custom-designed cryogenic atom probe microscope.
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