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Design flexibility is key to meeting diverse needs of electric transport

Image credit: Pailton Engineering

Electricity’s share in transport energy is projected to increase sevenfold from its 2011 level by 2050. Yet while great strides are being made with passenger vehicles, commercial vehicles and other heavy vehicles are slower on the uptake.

Look at progress toward the electrification of vehicles, and you’ll find a lack of uniformity. While electrification of passenger vehicles is accelerating, different sectors present their own unique challenges and opportunities vary depending on the type of vehicle. For this reason, uptake will be slower and more complicated in some sectors and we shouldn’t expect the success achieved with passenger vehicles to be easily replicated in every other sector.

According to many predictions, electrification of bus fleets will proceed at a rapid pace in the coming years. Around 17 per cent of the world’s buses are already electrified and Bloomberg New Energy Finance predicts the figure is likely to rise to 60 per cent by 2040.

The increase is being driven not only by improvements in the technology, but also by active government intervention. In California, for example, it is mandated that by the end of this decade any new purchases of bus fleets by mass-transit agencies must be of electric buses.

Looking at these figures, we need to consider the impact of the Chinese market. Of the 425,000 electric buses that were running in the world last year, 99 per cent were in China. The largest bus fleet in Europe was in London, which recently celebrated a deal to add 78 electric double-decker buses to its existing fleet of approximately 200.

For bus electrification to become more widespread outside of China, substantial infrastructural challenges will need to be overcome. Building expensive charging infrastructure in densely populated urban areas is difficult. However, charging is an equally significant problem for buses operating outside cities, which must travel longer distances and therefore suffer from even greater range anxiety. In the wake of the coronavirus pandemic, the sector will need significant government support and far-sighted policies to achieve the optimistic growth being forecast.

There’s also the issue of standardisation. Engineers and manufacturers have not coalesced around a standard for where in a bus the battery should be located. Competitive innovation will help drive the technology forward, but it also means that conventional parts of the vehicle such as the steering system must often be custom built.

Similar issues with range anxiety, lack of infrastructure and excessive battery weight hold back the uptake of electrification in the commercial vehicle sector. These vehicles face different demands in comparison to passenger cars.

For example, long-haul vehicles are heavier and so require larger and heavier batteries to get them moving. Research by Benchmark Mineral Intelligence has estimated that a 1,000-litre fuel tank weighing 800kg would provide the equivalent level of energy to a 20,000kg lithium-ion battery. Electric vehicles cannot travel as far on a single charge, when compared with vehicles that use an internal combustion engine. They also take longer to charge.

For all these reasons, uptake of electrification in this sector has been and will continue to be slower when compared to other vehicle types. Nor is it clear whether electric battery-powered vehicles will be better suited to this sector than other low-carbon alternatives like the hydrogen fuel cell.

In the meantime, there are alternative ways of reducing vehicle emissions. One option being explored is ‘platooning’, which involves linking two or more vehicles in a convoy, often employing automation technology. Another is greater emphasis on high-quality parts. Improved conventional components that can reduce both the overall weight of the vehicle and the friction generated while driving can also improve fuel efficiency.

The military sector is a major contributor to greenhouse gas emissions. For example, one academic study has concluded that if the US military were a country, it would be the world’s 47th largest greenhouse gas emitter.

The sector faces strong political pressure to reduce its carbon footprint and there are exciting reports of developments in hybrid technology. In August, for example, the UK Ministry of Defence announced its latest round of investments in electric and hybrid drivetrains. As well as the environmental benefits, advocates of alternative fuel types for military vehicles claim operational benefits, such as quieter and therefore stealthier vehicles.

However, there is good reason to expect that uptake of this technology in the military sector will proceed at a very slow pace. Diesel vehicles will continue to dominate in the coming years and the reasons behind this fact have more to do with the inherent limitations of the electric battery technology than with politics.

The key obstacle to electrifying military vehicles is the weight of the battery. If the vehicles are too heavy, they simply cannot perform or compete in the way a vehicle powered by an internal combustion engine would. This factor is particularly important in the context of rising demand for lightweight, nimble vehicles that are better suited to the asymmetric warfare and complex battlegrounds of the 21st century.

Different vehicles face different demands. The challenges and opportunities from electrification are not uniform across each sector. In comparison to passenger vehicles, many other sectors face a steeper uptake of the technology because of issues like greater range anxiety and inadequate infrastructure. In some sectors, it may be the case that electrification is still a long way off or is less viable than alternative means of cutting emissions. Design flexibility and innovation will therefore be key.

Roger Brereton is head of sales at steering systems specialist Pailton Engineering.

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