Hydrogen’s potential to be a major energy carrier has been the driving force behind the 36-year research career of John Curtin Distinguished Professor Craig Buckley.
Professor Buckley heads the Hydrogen Storage Research Group (HSRG) he established at Curtin more than 20 years ago. Since then, the group has developed a worldwide reputation and secured international collaborations.
Earlier this year, the Australian Renewable Energy Agency awarded the HSRG a $5 million grant for a project that is developing a hydrogen export product, which also involves the development of a pilot facility for hydrogen production and transportation.
In an episode of Curtin’s The Future Of, Professor Buckley explained the hopes and challenges for hydrogen as a clean green energy solution. This article is an edited version of our podcast discussion, which also discusses the HSRG’s research into green hydrogen and white hydrogen.
What are the differences between the ‘colours’ of hydrogen?
There are about eight ‘hydrogen colours’, depending on which website you’re reading. Brown hydrogen is hydrogen from the gasification of coal, which creates CO2 that’s emitted into the atmosphere. Grey hydrogen comes from splitting methane, which is natural gas, into hydrogen and CO2, which is emitted.
Green hydrogen is hydrogen produced via electrolysis from renewable sources, such as PV, wind and geothermal.
White hydrogen, some people call it gold, is basically hydrogen that comes from the ground naturally – which wasn’t known about until recently. It turns out that about 23 million tonnes a year of hydrogen comes from the ground naturally across the planet. If we can capture that, it would be a good source of renewable hydrogen.
What are the potential uses of green hydrogen?
There’s lots of applications – one of them is adding hydrogen into the natural gas network. But, of you go above 13% the appliance by may not be suitable anymore, because of the flame speed of hydrogen – it’s about eight times faster than methane. Years ago, the change from town gas to natural gas meant changing the appliances for natural gas. And we’ll have to do the same thing as we go closer and closer to 100% hydrogen.
We can add renewable hydrogen to nitrogen to produce renewable ammonia and add hydrogen to CO2 to produce synthetic fuels. You can also use it in industrial applications. One of the big things at the moment is green steel, with industries looking at using hydrogen instead of coal. Burning coal produces carbon monoxide, which reduces the iron ore and you get your pure iron, and a lot of CO2. If you add hydrogen instead of coal, and this is still a fair way down the track, the hydrogen reduces the iron oxide to get the pure iron, and what comes off is water. So, again, it mitigates the CO2. That’s a good thing about hydrogen – it can completely stop CO2 being formed.
How far off are we having 100% hydrogen?
For those pipelines, it could be a fair way off because hydrogen embrittles pipes. It’s so small, it can get into materials and form what we call a dislocation, or a defect. Ideally, it shouldn’t permeate but hydrogen will permeate nearly every material if you give it enough time. Our research group is investigating potential pipeline materials and coatings that may stop hydrogen permeating. Alumina is the best. The HSRG has a new project, ‘Aluminium-based hydrogen barrier coatings for gas transmission and distribution pipelines’, funded by the Trailblazer program. The industry partner is Cadoux Limited, a company that produces high purity alumina.
Hydrogen has always been your research focus – what drives your interest in this area?
Using metals to store hydrogen fascinates me. The big problem with hydrogen is the volume required. It has the highest mass–energy density of any known material on the planet, but its volumetric density at, say, room temperature and room pressure, is lousy.
For example, to fill your car up with hydrogen at one bar (one atmosphere in room temperature) you’d need a tank 3,000 times the size of what you have. So, we need to compress that hydrogen. If you compress gas at 700 bar, it’s 40 grams per litre. If you turn it into a liquid, it’s 70 grams per litre – much better, but you have to go to -253 degrees to get it to a liquid. That’s much colder than liquid nitrogen and way colder than your fridge. So, what other ways can we store hydrogen?
The metallic materials we’re looking at to store hydrogen can take twice as much hydrogen as liquid hydrogen. Some of these metal hydrides suck up hydrogen up like a sponge – up to 150 grams per litre. And to get it out, you just raise the temperature.
Will metal hydrides be the hydrogen storage solution?
I started the Hydrogen Storage Research Group in 2003, and originally our research was based on creating a metal hydride fuel tank for a car. You get a lot of hydrogen in there, but the mass of the metal required was way heavier than a current fuel tank. We now have a team of approximately 30, and one of our really interesting projects is with solid-state hydrides,
One of the challenges with hydrogen is being able to export it. We could produce it here using renewables, but how do we get it on a ship and send it overseas? Liquid hydrogen is one method, but you can lose up to 36% of your energy going to -253 degrees Celsius to turn hydrogen into a liquid.
Or you can use renewable hydrogen to produce renewable ammonia and send that overseas. But to get it back to hydrogen, you have to crack the ammonia by heating it to 400 or 500 degrees – that’s expensive and not a good process.
And another way is solid-state hydrides, and they’re really good. We’re working on sodium borohydride, in collaboration with the Western Australian company Velox Energy Materials and supported by a grant from ARENA, and we’ve made a lot of progress.
Basically, we can produce sodium borohydride in Australia using renewable energy – so no CO2 emissions – and then we ship it to Japan as a powder. Once in Japan, water is added, which produces hydrogen from the sodium borohydride, and you also split the water and get hydrogen from that as well. We get up to 21.3% weight, which is a lot, and we get 1.3 times more hydrogen from sodium borohydride than from ammonia because we’re also getting it from the water.
Once the hydrogen is produced, we can form what we call a borate. Then, we can send the borate back to Australia and use renewable energy to turn it back into sodium borohydride. So, it’s a completely recyclable process, which could become quite cheap to do.
The other thing about sodium borohydride is when you add the water to it hydrogen is produced at controllable pressures. We can get up to 1,000 bar pressure in the lab, and you might think, what for?
Well, if you go to a hydrogen refuelling station, the electrolyser splits the water and the hydrogen that comes out is 20 bar, and then an ionic compressor compresses it up to 900 bar. And then they dispense it to 700 bar for a car and 350 bar for a bus or a truck.
But we’ve got a process that just by adding water we can get up above that 900 bar, without a compressor – it happens in the process. This also could be, well into the future, a replacement for electrolysers.
The idea of green hydrogen has been around for decades, so why is it now seen as an energy solution?
The cost of renewable energy such as solar and wind has dropped drastically in the past couple of decades. It’s actually cheaper than using, say coal to produce electricity. In the past people baulked at using hydrogen because of the production costs, but now that CO2 and climate change is such a major problem, most countries have a price on carbon. There’s not a government mandate at the moment in Australia, but most of our industries have a price on carbon – they know it’s going to happen sometime and they factor it in.
The electrolysers have improved, the fuel cells – which are the storage cells – are more efficient. A fuel cell is the reverse of an electrolyser. With an electrolyser you use electricity to split water, to produce hydrogen. In a fuel cell, you put in hydrogen and oxygen and produce electricity and water. That’s why your car can run on a fuel cell, which will be basically electricity, and what comes out of the tail pipe is water. It’s completely reversible, so it makes a lot of sense. It’s much more feasible now to use hydrogen, using renewable energy to produce it. Even though you get less energy out than what you put in, it’s now a commercial prospect.
Are there other barriers to the adoption of green hydrogen?
The one that normally pops up is safety, but hydrogen is no more unsafe than fossil fuels we use every day. We drive around with a bomb in the back of our car, basically using petrol. We don’t worry about that, right? Hydrogen is no more dangerous, but it has special needs.
For instance, the temperature to ignite hydrogen is 585 degrees Celsius, whereas petrol is 220. The flame speed of hydrogen is eight times higher than methane and the ignition energy required is one-tenth of that for methane, but you need more hydrogen by volume for it to ignite – six times greater than for methane.
If you look at it overall, we produce 90 million tonnes of hydrogen per year. Most of it comes through steam reformation of methane, and that hydrogen’s handled quite well – you don’t hear of many accidents. It’s all done around the ports and handled on the refineries. There’ll be more safety procedures moving it into the public space, but hydrogen’s no more dangerous than what we’re already using.
And it can’t happen overnight. In 2019 Western Australia produced and exported 74 million tonnes of natural gas. If you wanted to export the same amount of hydrogen energy, you’d only need 34 million tonnes of hydrogen, because it’s got a higher energy content than natural gas. But, to produce that would need 1,836 terawatt-hours of electricity – to put that into context, that’s more than seven times greater than Australia’s total electricity production. So, we have to build the renewables first.
Also, to produce 34 million tonnes of hydrogen you’d need more than 300 gigalitres of water, but the mines are already using double that amount.
Desalination plants produce fairly pure water, which is needed for electrolysis, but they produce salt, which is an environmental concern. The salt will dissipate over time, but just locally. But overall, I don’t see any of these being insurmountable. We’ve been living on fossil fuels for the past 100 years and we got over those problems, mainly due to huge tax breaks. If you give those breaks to a hydrogen economy, I don’t see it taking long for it to take off.
What is the timeframe for the renewables needed first, to produce the amount of green hydrogen we’d need?
It depends on how much the governments get behind it, because industry already is starting to. Twiggy [Andrew] Forrest says that by 2030 he’ll be running his mining operations on renewables, and that will involve green hydrogen. Most countries are looking at 2050 as their target, but I think it’s got to be done earlier.
Australian state governments are supporting hydrogen projects and renewable-energy projects. There’s some touted for Western Australia in the gigawatt range. If these come online, then we’ll start having the renewable energy that can be used to produce hydrogen.
People say, why don’t we just use batteries? Batteries are fantastic for short-term storage, but once you want to go above 24 hours and seasonal storage, hydrogen is way better. For cars, batteries for short trips around the city are fine. But for trucks and buses, you need too many batteries. So hydrogen, which has much higher energy density than batteries, would be much better. You don’t need much hydrogen to run a car, in terms of mass. The world record for the longest distance travelled by a car on one tank was on hydrogen. [See WHICHCAR article].
Is the Hydrogen Storage Group doing any work with white hydrogen?
We’re looking more at how it can be detected. There are reports in the literature that say natural hydrogen can be formed when an iron ore source is available. There’s some interaction with water and iron ore that produces the hydrogen near the surface. Here in Western Australia we have heaps of iron ore. We probably have a lot of natural hydrogen coming up without realising it.
The HSRG is looking at detecting hydrogen using Raman scattering. It uses a laser and gives a nice signal for hydrogen. The future idea is to put this on a plane or a drone, fire the laser and see if you can detect the hydrogen.
We’re making the laser in the lab, first to show that it can detect hydrogen, and then we hope to be able to take it out in the field … And we have geologists at Curtin who are interested in researching where the hydrogen is occurring and why.
