Commercial Motor takes a look at what we can expect to see fuelling the trucks of the future and how the industry is making preparations (part two of two).
Most hybrid applications, though, use diesel/electric technology in one form or another. There are two basic hybrid concepts, series or parallel. In the latter, the diesel engine provides the primary tractive energy, with stored electricity being blended into the driveline.
This can happen either in situations where trucks are most fuel-demanding, under acceleration or climbing hills, or to eliminate exhaust emissions in sensitive areas.
The biggest limitation at present is the power density of traditional batteries. More efficient storage devices, such as high-density nano-technology battery construction and super-capacitors already exist and are only waiting for the economies of scale to make them viable.
You may well already own an example in the form of those paperback-sized power packs that will jump start a car repeatedly.
Series hybrids, or as they are becoming increasingly better known, range extending drivelines, don’t have a direct link between the diesel engine and the wheels.
They are effectively full-electric vehicles whose batteries are charged by the mains at the beginning of the duty cycle, then topped up by the diesel engine, which will typically be considerably smaller than normal.
It only needs to run at a constant speed, but on a Renault Range D currently being trialled by a French operator, driver feedback dictated a more linear relationship between engine and road speeds.
Hybrid systems aren’t just for traction, though. A growing number of applications use stored electricity to operate ancillary equipment, such as loading cranes, mixer drums and tail-lifts, silently and fume-free.
Full electric power looks to be the answer for inner city operations, giving zero emissions at the point of use. From a global perspective, though, the issue isn’t quite as clear cut. The politics of getting electricity into the National Grid is a whole story on its own, and depends on where you are.
You may recall a few years ago that Eurotunnel slashed its CO2 emissions simply by taking its supply from the other side of the Channel, where there is a greater proportion of nuclear generation.
In the UK, where virtually all of our reserve capacity currently comes from coal, the more electric vehicles plug in, the higher our overall CO2 emission level rises.
The timetable for more nuclear energy in the UK will be measured in decades, though, as the current Hinckley Point fiasco is demonstrating.
Be that as it may, the use of electric trucks is on the rise. In London, for example, about 10 Isuzu Grafters with full-electric drivelines by Paneltex’s Zeroed division are in operation. Over the Channel, Dutch converter Ginaf has an impressive line-up of electric vehicles available.
It ranges from a 3.5-tonne van based on the Iveco Daily, through to a variety of larger models based on Mercedes-Benz Atego and Antos models, some having as much as 110km of autonomy on 80% of battery capacity. Another van and a trio of Antos models have electric power with range-extender diesel engines.
Full-electric trucks face the same storage issues as hybrids but on a larger scale. At present, carrying enough capacity to provide the same energy as the 500 to 1,000 litres of diesel carried by a typical long-haul top weight artic would require such a weight of batteries as would leave no capacity for a load.
Energy on the go
The alternative to plugging in to the mains is to create your own electricity on the move. Until someone creates a small on-board nuclear reactor, we’re looking at hydrogen fuel cells.
We recently drove an operational prototype of a hydrogen-powered Renault in France, an experience just like driving a “normal” electric truck.
The downsides of hydrogen power currently are the energy efficiency, and cost, of producing the liquid fuel and developing the supply infrastructure. At present, hydrogen either comes from oil, or from electricity.
The UK government is behind the programme to develop the network, and the first publicly accessible filling stations already exist. Certainly, within a decade, we expect to see a realistic hydrogen supply in place.
The truth is that we see no golden bullet on the horizon. Until there is, we will have to work with what we have now. The good news is that what we already have represents an optimistic platform towards future needs; it just has to become more practical.
Our vision of the medium-term future is that diesel will continue to be the fuel of choice for long-haul goods transport, helped by higher levels of operational and technical efficiency.
For regional operations, hydrogen fuel cells are likely to play a greater role, assuming greater efficiency in its manufacture and the creation of an effective supply infrastructure.
Locally, it looks like plug-in electric vehicles are the way forward, a situation that will only grow as batteries become smaller and cheaper. In short, it’s going to be a long time before the road transport landscape looks radically different.
This article first appeared in Commercial Motor 17 December. Why not subscribe today?