Operating the tipping body and a grab, if one happens to be fitted, will draw current from the traction battery, and shorten the truck’s range between recharges. If a separate battery is fitted to power the body and grab, then that will add to the vehicle’s cost and unladen weight in what is a notoriously payload-sensitive sector of the market. The weight of the traction battery itself will reduce carrying capacity, too.
Then there is the risk to be considered of the battery getting damaged if the truck ventures off-road, the high-voltage safety hazard that may arise as a consequence, and the cost of getting the battery replaced, which could be substantial.
Tipper owners operating in urban areas may have no choice but to go electric, however, as local emission restrictions tighten. Oxford is already busy turning some of its city centre streets into a zero-emission zone during the working day. Tender documents may demand to know what operators are doing to minimise their impact on the environment before contracts are let.
Happily, opting for an electric solution brings certain operational advantages, points out Renault Trucks. Last year it supplied its first fully electric construction truck to French plant hire specialist Noblet Group.
A 26-tonne D Wide Z.E (Renault Trucks has recently started to use the E-Tech designation instead to denote its battery models) 6x2, it is equipped with a Jocquin tipper body and a Hiab X HiPro 142-E grab, and has gone into service in the Paris region. It boasts a steered rear axle for easier manoeuvrability and comes with a pack of four 66kWh batteries. The batteries can be recharged in less than 10 hours from a 22kW socket, says Renault, in less than two hours with a 150kW rapid charger, and a one-hour partial recharge from a 22kW outlet will provide an extra 15km to 20km of range. A partial recharge can of course compensate for any loss of battery capacity if a grab or tipper body is being used intensively.
And the advantages referred to earlier? Neither the body nor the grab are driven by a diesel engine, which means both they and the vehicle itself operate more quietly than they would otherwise do, points out Renault. That means urban and suburban householders have to endure less noise. That is a definite benefit if the truck has to be deployed early in the morning, or late at night.
Diesel exhausts can raise dust on construction sites, which blows everywhere on dry days to the discomfort of workers and nearby residents. As a consequence, vertical exhaust stacks usually have to be fitted; no need to worry about that if you go electric, says Renault.
UK APPLICATION
Back across the Channel, Blackpool-based Fox Group, which hauls aggregates and recycled materials and carries out muckaway work, is putting a pair of Volvo FE Electric 6x2 tippers into service. They are the first of their kind in the UK. Fitted with Thompson bodies and steered back axles, they are plated at 27 tonnes rather than 26 tonnes – a 1,000kg concession which helps to compensate for the weight of the battery pack, and should mean there is no reduction in payload capability. Each of the Volvos is equipped with a pair of electric motors and a two-speed gearbox – and with 400kW/529bhp and 850Nm on tap, neither of them can be said to suffer from a lack of power or torque.
Range is clearly less of an issue with tippers, which work predominantly locally, than it is with tractor units on intercity work. The Volvos should be able to cover 150km between recharges, which will take place overnight.
Fox Group’s managing director, Paul Fox, is convinced that electrification is the direction to head in, despite the challenges it presents. “We’re strongly committed to playing our part in the UK’s push to reach net zero carbon emissions, and we’ll be adding more electric trucks to our fleet in the future," he says. "We believe that if the country is serious about substantially reducing carbon emissions, then the construction sector needs to come to the party."
While electric tippers may be fine on city streets, they may fare less well on construction sites, where driving conditions are likely to be a lot rougher; and the batteries potentially far more likely to come to grief. Assuming the batteries and high-voltage cables are reasonably well-protected, the danger is less acute than it once was, says Scania director of e-truck solutions and sales management, Anders Lampinen.
In some countries, tippers are still expected to wallow in mud, he agrees, and you need an 8x8 chassis to make any progress. In many others, however, the site operators put the roads in first. While those may not be fully finished, a tipper should be able to drive over them and tip without getting into difficulties. Electric Scania tippers are now going into service across Scandinavia, he says, including one in the LKAB iron ore mine at Malmberget in northern Sweden. Running it underground creates zero health problems because it is zero-emission. The mighty Malmberget tipper weighs in at 49 tonnes gross. Says Scania head of e-mobility, Fredrik Allard: “It’s the first of its kind, and another really big step on the journey towards sustainable transport solutions across all applications.”
FUTURE OPTIONS
Dropping down the weight scale, electrifying a 32-tonne 8x4 tipper is more problematic than creating a zero-emission 6x2, given the need to find sufficient space on the chassis for the batteries required to make it operationally viable. The operator might be able to specify a shorter day cab and have some of them mounted behind it, but it is a moot point as to how acceptable this would be to drivers. It would also create complications if a grab had to be installed. “You would probably need to go for a tridem set-up with a steered rear tag axle,” Lampinen observes.
That would pose difficulties in the UK. In most other markets tridems can operate at higher gross weights than are permitted on this side of the Channel. “In Sweden for example they can run at 56 tonnes, and in the Republic of Ireland they can operate at 39 tonnes,” points out a Volvo spokesman. In Britain however, and in line with standard twin-steer 8x4 chassis, they remain limited to 32 tonnes; and in a regulatory quirk, there is no weight concession for going electric as there is at 26 tonnes, he says.
“That means that if you fit sufficient battery capacity to give you a 280km range, then you will lose around a tonne of payload capacity,” the Volvo executive observes. Not something tipper fleets are likely to applaud, no matter how environmentally conscious they are. This could prompt tipper operators who want to cut emissions to go the artic route, opt for an electric 4x2 tractor unit plus a short tri-axle tipper trailer, and run the five-axle combination at 40 tonnes.
“It would be cheaper than buying an electric tridem,” he observes. “And you’d be able to carry more.”