Transformative truck propulsion technology

Welcome to the inauguration of ‘The Tech’s Files’, a new monthly series that explores topical technical issues impacting the trucking industry. The tech is out there!

In the first edition, we’re looking at next-generation propulsion – the alternative fuels and engine/motor tech that is likely to transform the industry in 2023 and beyond.

But why is this change even happening? After all, diesel has an incredible track record, successfully powering the trucking industry for the past one hundred years. The answer centres on that incredibly useful but somewhat pesky sixth element in the periodic table – carbon, and its contribution to climate change.

To combat climate change, Australia’s government has enshrined into law an ambitious emissions reduction target – 43% below 2005 levels by 2023, and net zero by 2050. This is an extraordinary goal, and one that the trucking sector will be instrumental in achieving, currently contributing to approximately 5% of Australia’s total emissions[1],[2].

Is the industry ready for this change? You bet. More than ready. In a strong display of commitment, one hundred industry companies and organisations recently united in support of the Electric Vehicle Council’s push for action and policies[3], with the goal of 1 million battery electric vehicles on Australian roads by 2027.

Right now, engineers and technical staff both in Australia and abroad are refining and developing the new technologies that will achieve this goal. So let’s dive into the world of battery electric vehicles, hydrogen burning engines, and hydrogen fuel cells.

Battery electric vehicles (BEV)

Battery electric vehicles ‘evolved’ from the diesel-electric hybrids that arrived on the scene in the mid-2000s. While bridging the gap between the old world and the new, hybrids didn’t transform the industry, and they cannot deliver emissions reductions of the scale necessitated by the government’s target.  

BEVs go one step further by ditching the diesel engine altogether and relying on larger electric motors and batteries that are primarily charged by plugging into the grid, or when on the move using regeneration.

Unlike hybrids, there have been some big developments in the BEV space recently. Major local logistics player Team Global Express recently announced plans to deploy a fleet of 60 electric trucks in Queensland, comprising 24 Fuso eCanters and 36 Volvo eFLs. It is set to be Australia’s largest electric freight vehicle fleet, and the orders placed with Daimler and Volvo are the largest orders received for those vehicles anywhere in the world, to date.

The Fuso eCanter has a GVM of up to 7.5 tonnes in 4×2 configuration. The Volvo eFL is larger, having a GCM of up to 16 tonnes, again in 4×2 configuration. Range is claimed to be 100 km for the eCanter, and up to 300 km for the eFL, depending on duty cycle.

This technology can deliver the transformative change that both the industry and the government is aiming for, provided they are powered by low or zero carbon energy. In the case of Team Global Express, the vehicles will be charged on-site in Bungarribee using an industrial-scale solar power and battery storage system.

Range between re-charging sessions remains the most topical drawback. The reason is energy density, which refers to the amount of energy stored in a single, defined ‘unit’ of something, and is usually expressed in terms of volume or mass. As an example, diesel fuel has an energy density of about 45 Megajoules per kilogram. In contrast, the lithium-Ion batteries that are used in most battery electric vehicles boast only one-hundredth that figure. This explains why a few hundred litres of diesel is equivalent to several tonnes of batteries in terms of travel distance.  

Hydrogen (as a combustible fuel)

Can the range problem be solved by hydrogen? Maybe. Using hydrogen as a combustible fuel is a cool solution as it has one foot in the past, and one in the future. The futuristic aspect is the fuel, which releases almost no carbon dioxide when combusted. The historical aspect is the engines, which are technologically similar to natural gas engines, yet function in almost the same way as a conventional diesel engine, including performance, reliability and longevity.

Several major truck OEMs are currently developing this technology, including DAF[4] and MAN[5]. Cummins revealed a medium-duty internal combustion engine truck at the IAA truck expo in Hannover in late 2022. The concept used a Mercedes-Benz Atego 4×2 truck, offered a GVM up to 26 tonnes, and potential operating range of up to 500 km.

On the flip side, hydrogen combustion engines suffer the same inefficiencies as diesel engines, but can partially fix the range issue. The limiting factor is the thermodynamic properties of hydrogen itself. As a gas, it occupies a relatively large volume even when compressed in a tank under pressure. This means that large tanks of hydrogen gas are required where range is a concern, which may eat into a truck’s usable loadspace. Liquifying hydrogen does not solve that issue either, as it does not liquify unless cooled to a bone-chilling minus 235 degrees Celsius – requiring highly-insulated cryogenic tanks for storage and transport.  

Additionally, hydrogen also introduces a new problem – the infrastructure network required to supply hydrogen fuel to vehicles does not presently exist, and would require billions of investment and many years to become a reality. In addition, the production of hydrogen itself is energy intensive, so unless low or zero carbon energy is used in its production, any exhaust pipe emissions would be negated.

Hydrogen (to power a fuel cell)

The second option for hydrogen is to be used in a fuel cell to create electricity, which is then used to power an electric motor. Fuel cells are electrochemical energy conversion devices – in simple terms, they extract some of the chemical energy of hydrogen, convert it into usable electricity, and then combine it with oxygen in the air to produce water vapor at the ‘exhaust’.

This solution is the most complex of the transformative truck propulsion technologies, yet is charging forward at a rapid rate, with several truck recent major OEMs announcements:

  • Hyundai developed ‘XCIENT’ the world’s first hydrogen fuel cell heavy-duty truck in 2020[6], currently under trial in Switzerland
  • Volvo and Daimler announced a hydrogen fuel-cell joint venture in 2021, called ‘Cellcentric’[7]
  • Hyzon motors are planning to supply five 140-tonne rated triple road train hydrogen fuel cell trucks to Ark Energy to transport Zinc between Sun Metals Townsville mine and the Port of Townsville in mid-late 2023[8]

Hydrogen fuel cell vehicles are impacted by the same transport and storage issues as hydrogen-burning vehicles, but have one distinct advantage – efficiency. Like diesel engines, hydrogen engines can only achieve thermal efficiencies of 30-35% (meaning that most of the energy available is lost as waste heat), but a hydrogen fuel cell can be up to twice as efficient, achieving an efficiency of around 60%[9], meaning far less hydrogen is required to travel the same distance.

Where does this leave us for 2023 and beyond? Which technology has the highest likelihood of replacing diesel and fuelling road freight for the next century? The major players have likely already placed their bets. BEVs are the ‘short’ game, being available now, and chargeable using current infrastructure. Hydrogen is the ‘long’ game, requiring relatively greater investment, but fixing the main disadvantage. In both cases low or zero carbon energy must be used, else the environmental impacts are the same.

Major technological developments on either side could be incredibly disruptive. A new type of battery that delivers a ten-fold improvement in energy density? New ways of storing hydrogen in solid states by combining it with other materials? There are a lot of possibilities, but no matter which way the industry goes, it’s an incredible transition to participate in.   










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In this edition of ‘The Tech’s Files’, HVIA’s monthly series that explores topical technical issues impacting the trucking industry, we’re…

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