Diesel still the future for long-haul, says Renault

The fuel of the future for long-haul road transport is diesel, according to Renault Trucks alternative energies development director François Savoye.

As part of the manufacturer’s recent Alternative Fuels day, Mr Savoye showed a graphic which demonstrated various alternative fuels rising to ascendency and then fading away in the urban and distribution sectors, while diesel remained the best solution for long-haul.

Various factors would shape change in the transport fuels market, including the introduction of the EU’s VECTO CO₂ emissions model, and the “demonisation of diesel” which was leading to the fuel being phased out in some cities.

When it came to road transport fuel “the perfect solution does not exist,” he said.

“For the long-haul, diesel remains the optimum, but the time of ‘all diesel’ across all segments of road transport is over.

“There is no prospect of electric-only power in long-haul trucks. A 1,000 km range would require a nine-tonne battery! But diesel is going to have to become more fuel-efficient, there is going to have to be more electrification on the vehicle and greater use of biofuel.

“Diesel’s biggest problem is now image,” he asserted.

The introduction of Euro 6 engines in 2014 had seen a 97 per cent reduction in particle emissions and a 98 per cent reduction in NOx. Brakes and tyres now each produced more particles than the engine exhaust, and engines remained in conformity for seven years and 700,000 km.

French-produced biofuel would reduce diesel’s CO₂ emissions by 60 per cent in ‘well to wheel’ terms, but there was a price to be paid in terms of increased fuel consumption and maintenance requirements.

Using synthetic ‘gas-to-liquid’ fuels could yield well-to-wheel CO₂ reductions from 50 to 90 per cent and with no operational constraints.

Compressed natural gas used the simplest hydrocarbon fuel: methane. Gas was a good solution in areas where it was plentiful, and electricity was ‘dirty’ ie coal-generated. But it would be a transitional fuel as urban and regional distribution moved to electricity.

Renault had introduced its first all-electric truck, the 7.5-tonne Maxcity, in 2010. Its current electrical range spanned the 3.5 – 16-tonne range, and 40 electric trucks had been sold in five years. This was set to change, with the second-generation range now extending to 26 tonnes and being offered for diverse applications including last-mile deliveries, city distribution, waste collection and even heavy-duty urban logistics in limited-series production.

The shift to a greater range of electric vehicles had been enabled by a joint venture between Renault Trucks’ parent Volvo Group and Korean company Samsung, which ensured responsible sourcing of battery materials, respecting the environment and human rights.

In urban refuse collection, trucks typically covered 65 km a shift with lots of stopping and starting. Using electric power would cut the annual fuel bill for a truck from €30,000 to €2,000. Urban distribution covered 100 – 150 km a day, comfortably within the 200 km range of an electric Renault truck.

Currently, electric truck prices were three or four times higher than diesel, but full operating costs were only one-tenth of diesel.

“The total cost of ownership is currently the same, although all the parameters have completely changed. The Samsung alliance secures battery technology for the long-term, and the price of batteries will come down.”

In terms of gas, Renault Trucks had chosen not to use Volvo’s heavy-duty gas technology.

Mr Savoye explained that each brand within the Volvo Group was responsible for its own profit and loss, and could choose which Group technologies to adopt.

“Renault is still confident that diesel is best for long-haul; gas will only be a niche in this market.”

The Renault gas offering uses proprietary technology from outside the Volvo Group: the nine-litre Cummins L-series engine of 320 hp driving through an Allison automatic transmission, in two or three-axle Range D chassis.

“Hydrogen is part of the energy landscape, but is 10 to 20 years away in areas where the grid can charge vehicles directly. It addresses issues of range for electric vehicles as it has better energy density than battery power and offers faster refuelling.”

On-vehicle fuel cells turn hydrogen into water, liberating electricity.

“A hydrogen truck is an electric truck, so for the moment Renault will concentrate on battery electrics – once hydrogen power is mature enough it becomes another option.”

A brief circuit of a wet test track in an unbodied tri-axle Range D Z.E. Wide revealed the truck to have a very responsive acceleration, with sharp retardation supplied by the regenerative braking of the drive axle, and the whole performance happens in near silence. Two electric motors are used, giving a total maximum power output of 370 kW, driving through an automated two-speed box.

Range depends on the battery size specified, but real-world distances of up to 200 km are claimed possible.

We also drove a RCV-bodied 18-tonne gas-powered Range D Wide. Its compressed natural gas (CNG)-burning, nine-litre 320 hp Cummins straight-six drives through an Allison six-speed fully-automatic transmission, with the latter’s torque converter effectively compensating for the spark-ignition engine’s comparative lack of bottom-end power.

In environmental terms, Cummins claims that this driveline, originally developed for city buses, has achieved close-to-zero emissions of both NOx and particulates, way below the levels produced even by Euro 6 diesels.

It’s an ideal solution for the municipal end of the market, where drivers are well-used to the Allison transmission, and the quiet gas engine will reduce the noise and intrusion of on-street bin collections. There’s no SCR system or particulate filter regeneration to worry about, either.

Renault is not expecting high initial demand for either gas or electric trucks in the UK, and the gas version will only be available as a post-production conversion from left-hand drive.

The alternative driving experience was completed by a similarly brief drive in a Master Z.E. van. The unladen vehicle was quiet and quick off the mark, and with the batteries mounted under the seat in place of the diesel tank, full load capacity was retained.

All three vehicles seemed considerably more relaxing to drive than their diesel counterparts, although on a long shift ‘range anxiety’ in electric vehicles might add stress as the working day wore on.

Simultaneous with the Renault Trucks alternative fuel day was a separate announcement by Groupe Renault (which is independent of Renault Trucks and Volvo Group) that it would have hydrogen-powered versions of the Kangoo and Master Z.E. vans available next year.

The Master range is sold by both Groupe Renault car dealers and Renault Trucks heavy commercial dealers.

Groupe Renault says switching to hydrogen fuel cells in place of conventional batteries will extend the Master Z.E.’s range from 120 to 350 km, and the 3.5-tonne vans should be on sale by the middle of next year.