The Mining Magazine Intelligence Future Fleets Report 2023 casts a spotlight on diverging trends in the decarbonisation of mining. While battery and electric technologies are dominating the industry's efforts to phase out fossil fuels, a small but determined group of insiders believe hydrogen is the way to go.

Andrew ‘Twiggy' Forrest, former chief executive and current non-executive chairman of Fortescue Metals Group (FMG), created a media splash in 2021 when he announced plans to generate hydrogen from renewable energy (so-called ‘green hydrogen') and use it to power his iron ore empire in Western Australia's Pilbara region.

The Future Fleets Report (FFR) features insights from representatives of Hitachi and Caterpillar, who also outline their companies' commitment to hydrogen technology. Caterpillar, in particular, pointed out that its modern engines could run on a 5-10% hydrogen blend, with hundreds of thousands of operating hours on some machines using up to 60% hydrogen.

But others, such as Professor Peter Newman, who studies sustainability at Curtin University, told the ABC in 2021 that electric vehicles have ‘won' the battle for transport, and a Hitachi spokesperson told Mining Magazine that developing hydrogen technology was a lower priority for the company than battery and trolley-assist systems.

The FFR shows that no more than 7% of future-looking trucking capacity in the mining world is run on hydrogen, with more operations looking at hybrids. So, is it really worth pushing forward with green hydrogen technology in the mining industry? 

 

Extra power

Hydrogen holds an advantage over batteries for sheer power output in mobile equipment - there is minimal chance of batteries powering large haul trucks in the near future, for example.

But the biggest factor inhibiting the uptake of hydrogen is not the power generation technology - like battery technology, there are almost endless fuel-cell designs in all stages of development, each an improvement on the last. Instead, the problem is the hydrogen itself.

By far the greatest challenge is the storage and transportation of hydrogen fuel. Because of hydrogen's exceptionally low density, compressing it as much as possible is essential to transporting and storing it using realistic infrastructure. It would be ideal to do this in its liquid state, but that requires a temperature of -253C, so instead it is compressed to around 80,000kPa - compare this to just 25kPa for LNG.

On top of the resultant risk of explosion, everyone who has seen a photograph of the Hindenburg knows that this is not hydrogen's greatest danger. It will ignite in air at concentrations of anywhere from 4% to 75% (compared with 5-15% for LNG) and can even do so without a source of ignition. Leaks can therefore be catastrophic.

Crucially, these are unchangeable facts about the nature of hydrogen. It is very unlikely that miraculous technological advances will resolve these problems any time soon.

None of this should rule out the use of hydrogen in mining. Industry and scientists know perfectly well how to handle it safely, and indeed tonnes of it are used every year for purposes such as ammonia production. These logistical challenges, however, would certainly cause most miners to think twice before signing up for a whole new fleet of hydrogen-powered trucks.

Mining's advantage

If the industry really wants to push hydrogen forward, mining has several advantages that mean it could be the very sector to provide the real-world problem-solving and testing the technology needs to progress. And not just any hydrogen: zero-emissions green hydrogen.

Many large mines, especially open pit bulk mining operations, lie in remote areas with renewable energy available on tap - think of solar power in the Pilbara, for example. Using these resources to generate hydrogen on-site, or close by, would virtually eliminate the transport and storage problems that are the major stumbling block for fuel-cell adoption at the moment. Additionally, the large vehicles involved in mining would mitigate the obstacle of on-board fuel storage space that smaller vehicles face.

Naturally, the construction of anything beyond a prototype-sized green hydrogen production facility would be a colossal investment, even for the biggest mining company. The first steps would have to be taken by companies with immense, power-hungry operations grouped in close proximity to each other.

Again, the Pilbara region, where Rio Tinto, BHP and FMG run collections of vast iron ore mines, is an excellent candidate for such an experiment. In this respect, it is unfortunate that FMG's renewable energy arm, Fortescue Future Industries, has chosen locations for its planned hydrogen projects that are too far from the Pilbara to nullify transport and storage problems.

To somewhat offset the costs involved in transitioning to hydrogen power, it may be possible to retrofit existing machinery instead of investing in an entirely new fleet. The FFR highlights the work of a team at the University of New South Wales that managed to retrofit a diesel engine to run on 90% hydrogen and just 10% diesel, reducing its emissions by nearly 86%. It's a small saving compared to the cost of hydrogen infrastructure, but everything helps.

The fact is that no matter which path the mining industry takes towards decarbonisation, there are going to be substantial up-front costs. These should be mitigated over the long run by savings on everything from fuel to ventilation systems, but it will always be difficult to convince investors to pony up such large chunks of cash all at once.

As with other new technologies that improve safety and environmental impacts, it will inevitably be the largest miners that blaze the trail. The mines profiled in the FFR for their future-facing fleets are, by and large, owned and operated by some of the biggest players in the game. As the technology gets better and cheaper from lessons learned during these pioneering investments, ever-smaller operations can begin to reap the benefits.

If green hydrogen is to make a real difference, it will have to be through this trickle-down effect. The question is whether the advantages it offers are enough to inspire the investment needed to overcome its significant drawbacks. Twiggy Forrest certainly thinks they are, and it's possible he's correct, but perusing the FFR 2023 shows precisely how far ahead batteries and electrification are in the race to zero emissions.