The Dieselgate emissions scandal did not involve the trucking sector, yet it would be entirely naïve not to recognise that diesel’s reputation across the board has suffered. It is certainly true that diesel fuel quality and engine efficiency have improved tenfold in recent decades, and the rise of exhaust emissions control technology, such as catalytic conversion, have improved air quality across multiple major markets.
Yet even in the world’s most developed nations, urban hubs—London being an example—are still subject to unhealthy levels of dangerous emissions, such as carcinogenic particulate matter (PM). That some cities are still experiencing bouts of smog of in 2019 is indicative of a need for further, radical change.
Without a revolutionary step change in the technology, batteries do not cut it for long-haul, heavy duty trucking, and while some see potential in hydrogen fuel cell technology, the infrastructure is still lacking
What’s more, incoming greenhouse gas (GHG) regulations for the heavy duty sector in both the US and the EU mean alternatives to fossil fuel burning are needed if fleets, and by extension truck makers, are to stay in business. There’s also the question of pollutants created by diesel not yet regulated, but which could certainly become so: the trucking sector is already ahead of the passenger car sector in this regard, in that it limits emissions such as ammonia, but such is the complexity of diesel emissions, often muddied by incomplete combustion, that further government intervention on the fuel cannot be written off. In short, claims of ‘clean diesel’ are surely no longer credible in this environment.
The fact remains, however, that without a revolutionary step change in the technology, batteries do not cut it for long-haul, heavy duty trucking, and while some see potential in hydrogen fuel cell technology, a zero-emission powertrain nearly identical to the diesel fuelling process, the infrastructure is still lacking. Diesel’s continued use in trucking is guaranteed for the long-term, as its power, efficiency and reliability simply cannot be beat. But truck-makers must recognise that in addition to the challenges faced above, image-conscious fleets keen to be seen positively by a society waking up to the very real threat of climate change. If the trucking sector is to carry on using diesel—and it will—it must do so in the most responsible ways possible.
One option gaining traction is hybrid configurations. Volvo has previously expressed some interest in the idea: its 2017 concept was reportedly capable of cutting emissions by 30%, and had some zero-emission capability, albeit only with a range of 10km (6 miles). Improving this could allow for the use of diesel on long-haul segments of journeys, switching to battery for sensitive areas where diesel use is restricted.
That some cities are still experiencing bouts of smog of in 2019 is indicative of a need for further, radical change
However, the major manufacturers have been slow to bring anything viable to market. Daimler’s fully electric Freightliner eCascadia seems closer than most, but with a range of just 400km (250 miles) and recharge times of at least 90 minutes, it is unlikely to appeal to the hyper cost-sensitive long-haul market.
Meanwhile, alternative fuel use continues to gain traction. UPS recently made headlines with the largest purchase of renewable natural gas (RNG) made by any company in the USA. RNG, says the company, is a key part of its strategy to reduce its ground fleet’s greenhouse has emissions by 12% by 2025. The lifecycle emissions reductions can be considerable, but concerns have been raised over the overall availability of the fuel.
For many, electrification of fleets may seem the ideal goal, but getting there will take a substantial amount of time, requiring long-term investment and innovation. The world cannot wait that long, and some positive step-changes are needed today if the industry is to tackle climate change and local pollution effectively. Few of these involve discarding diesel altogether: the fuel will remain integral to the sector for decades to come. It is down to automakers to help clean up its act.
Automotive World’s July 2019 special report, ‘Does diesel have a future in trucking?’, is available for download now