Driving Diesel Engines In A Hydrogen Race
It’s a new hydrogen-diesel hybrid engine affectionately known as “Baby Number Two” that will help decarbonise some of Australia’s heaviest indus
Converting mining industry vehicles to hydrogen could mean huge savings in CO2 emissions
The test rig is huge – it has its own room attached to the lab and looks like any other big motor at first glance, but beneath its metallic skin lies game-changing technology.
Engineers at the University of New South Wales (UNSW) say they have successfully modified a conventional diesel engine to use a mixture of hydrogen and a small amount of diesel, with their patented technology reducing carbon dioxide (CO2) emissions by more than 85%.
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This is the work of Prof Shaun Cook and his team at the university’s School of Mechanical and Manufacturing Engineering.
“The interest in converting an existing diesel engine into a clean-burning hydrogen engine is very high,” Professor Cook tells the BBC at his laboratory in Sydney. Inquiries have come from Germany, South Africa, Brazil, Japan and China.
“We will be installing a hydrogen direct injection system into existing diesel engines, which can be applied to any conventional engine,” he adds.
What makes his system unique, according to Professor Cook, is the way it mixes hydrogen and diesel and then introduces it into the engine cylinder for combustion.
Prof Cooke says there is “extremely high” interest in running diesel engines on hydrogen.
Unlike fossil fuels, hydrogen does not produce CO2 when burned, so it has long been seen as a green fuel source.
About 90% of the fuel in a UNSW hybrid diesel engine is hydrogen but it must be applied in a carefully calibrated manner.
If hydrogen is not introduced into the fuel mixture at the right moment “it creates an explosive that burns the whole system,” explains Professor Cook.
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He says studies have shown that controlling the mixture of hydrogen and air inside an engine’s cylinder can help negate harmful nitrogen oxide emissions, which have been an obstacle to the commercialization of hydrogen motors.
The Sydney research team believes that any diesel trucks and power equipment in the mining, transport and agricultural sectors could be retrofitted with the new hybrid system in just a couple of months.
Electric and hybrid vehicles are already advanced and Prof. Cook suspects that hybrids are of more interest in the car industry, which is replacing diesel cars.
However, he says Australia’s multi-billion dollar mining industry needs a fix for all its diesel-powered equipment as soon as possible.
It is a normal diesel engine but runs on 90% hydrogen
“We have so many diesel-powered generators, mega-trucks and underground machines. How do we decarbonize all the existing diesel engines? One way is to shut them all down and get new technology, which will take decades,” he says.
The plan is to run on a hybrid hydrogen-diesel mixture or revert to diesel only in the absence of hydrogen.
Professor Cook hopes his new generation engine will be a commercial product within two years.
Tim Buckley, director of Sydney-based public interest think-tank Climate Energy Finance, believes the technology has the potential to “dramatically transform the Australian mining industry”.”There’s always an element of scepticism in the work I do to evaluate what’s hype and promise versus reality. Having said that, the University of New South Wales’ progress seems quite material. If they can pull it off, it’s a huge opportunity,” he says.
An Australian team is in a global competition to develop hybrid diesel-hydrogen engines. Engineers in other countries are working on their concepts and designs but the Sydney team believes it has the edge.
“I think we can achieve a higher percentage using hydrogen over diesel compared to other research groups in the world,” explains UNSW PhD student Xinyu Liu from China.
“CO2-wise, Emissions-wise we can execute more reductions than other procedures. The concept has been proven using a previous small-scale engine. We are trying to implement this idea on a larger scale, which is more [applicable] to industry.”
PhD student Xinyu Liu (left) says the UNSW team’s research is ahead of other diesel-hydrogen projects.
The larger version, or UNSW’s “Baby Number Two”, has twice the volume of the original model and, according to Professor Cooke, is capable of “huge reductions in CO2” emissions.
This view is laid out in a paper published in the International Journal of Hydrogen Energy.
Much of the discovery’s impact on the environment depends on where the hydrogen comes from.
While a small amount of hydrogen is extracted directly from the ground, most of the hydrogen is made in the process by emitting CO2.
Green hydrogen, produced by using electricity from renewable energy to split water into hydrogen and oxygen molecules using an electrolyser, appears to be the answer. But the technology and electricity required are expensive, so only a small amount of hydrogen is currently produced this way.
But costs are likely to come down, and with abundant sunshine and wind, Australia has plenty of capacity to generate renewable electricity that could one day be used to make more green hydrogen.
The Climate Council, an independent organisation, believes sustainable hydrogen offers Australia an opportunity to end its reliance on fossil fuels.
“Australia is one of the world’s largest exporters of coal and the largest exporter of liquefied natural gas,” the council wrote in its 2021 briefing. “Both are polluting fossil fuels and Australia is paying a higher cost with more extreme and frequent extreme weather events such as bushfires, heatwaves and drought.”
Australia has great capability for renewable energy, which can be used to produce green hydrogen
For now, the UNSW project remains a nursery in the laboratory. An academic effort requires the financial strength of outside investment and the input and know-how of a mining company or engine manufacturer.
“Our vision is to impact Australia’s mining, agriculture and construction industries first and then move to other parts of the world to have a bigger impact,” says Professor Cook.
Australia has some of the largest resource companies in the world and they are all committed to aggressive decarbonisation targets. Technology is important.
“The idea of mixing hydrogen and diesel together in an existing engine is the holy grail for decarbonising heavy industry and mining,” says Tim Buckley.
He has this practical question for the engineers at UNSW: “Can they deploy it in a commercial setting and replicate it outside the university?”