18-month trial of 16t battery-electric truck returns positive technical and environmental results; range the only issue
04 April 2014
Logistics specialist STEF has been testing an experimental 16 tonne all-electric vehicle under actual operating conditions for Carrefour France. Developed by Renault Trucks on a Midlum vehicle chassis in partnership with PVI and IFP Énergies nouvelle, the truck covered 16,000 km and delivered 600 t of goods. This electric vehicle recorded a drop of 86% in well-to-wheel (WtW) CO2 emissions compared with its equivalent equipped with an internal combustion engine.
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| Battery-electric Midlum. Click to enlarge. |
The drop in WtW CO2 emissions was calculated on the basis of the French energy mix, which is 92 g of CO2 for the production of 1 kWh (source: International Energy Agency 2011).
If this figure is applied to the tonne carried, it represents only 2.3 kg of CO2 emitted per tonne. That’s seven times less than an equivalent diesel vehicle. When used under actual operating conditions, this vehicle demonstrated it consumed only 0.95 kWh per kilometer travelled. This is very little and all the more remarkable since that figure not only includes the energy needed for the vehicle’s propulsion, but also the power used for operating auxiliary equipment such as the cooling system for the refrigerated body or cab heating.
—Christophe Vacquier, Renault Trucks’ product manager
The battery-electric 16 t Renault Midlum features a 103 kW electric motor powered by 2lithium-ion battery packs with a total energy of 170 kWh (battery weight: 2 tonnes). Payload of the vehicle is 5.5 t. Another pleasant surprise coming from this real-life test was the vehicle’s capacity to convert its inertia into energy.
During deceleration phases, the propulsion motor becomes an electrical generator which recharges the batteries. 25% of the energy used by the vehicle comes from this generator. This is a very high figure and rather unusual for an electric vehicle. Here again it is able to make energy savings and it proves the driver had been able to drive it in the most appropriate manner.
—Christophe Vacquier
The only technical problems reported were due to settings or bad electrical contacts, which were rapidly rectified.
The quiet running vehicle enabled access to a night-time delivery slot (from 5 AM to 7 AM), noted Nadège Doubinsky, vehicle technical director for STEF. However, he added,
The only point that needs improving is the vehicle’s operating range. 100 km [62 miles] is not enough for the length of rounds we do in the town center.
The test was conducted in two phases. The first was from June to December 2012, with the vehicle delivering fresh products to three Carrefour City stores in Lyon, with rounds of about 40 km (25 miles) a day. The second, from January 2013 to the end of December 2013, involved the vehicle delivering frozen products to six Carrefour Market shops in the Lyon area with rounds of some 90 km (56 miles) a day.
The length of the test made it possible to see how the vehicle performed under all weather conditions and in temperatures ranging from -8° to +32°C.
If the truck consumes 0.95 kWh / km and has 170 kWh of batteries, how does it only have a range of 100 km?
Shouldn't the range be somewhere around 130-150 km/h accounting for some amount of reserve?
Posted by: Dave R | 04 April 2014 at 01:36 PM
The only problem is short range...Duh.
Posted by: Mannstein | 04 April 2014 at 06:47 PM
Dave R, because they don't fully discharge the battery to preserve battery life. It's usually only about 66% of capacity. For example, the Volt has 16kWh capacity, but is only allowed to draw down 10kWh.
Posted by: Sean Prophet | 04 April 2014 at 07:24 PM
That is an insane amount of reserve capacity for an EV pulling 100 kW out of a 170 kWh battery.
The LEAF uses about 21 kWh out of 24 - 88%.
A similar ratio in this truck would leave about 150 kWh usable, good for ~140 km.
That is assuming that the 0.95 kWh / km is measured at the battery. If they are measuring that at the wall, then the efficiency at the battery would be somewhere between 5-15% higher depending on the efficiency of the charger.
Posted by: Dave R | 05 April 2014 at 12:03 AM
Shouldn't the range be somewhere around 130-150 km
If they had used Toshiba/Altairnano titanate batteries, they could discharge farther and charge more quickly, they would also last much longer. The space required would be greater, but a truck has the room.
Posted by: SJC | 05 April 2014 at 11:16 AM
The Leaf went deliberately aggressive at the cost of longevity. I would trade range for longer life. The Volt battery is likely good for at least 10 years. The Leaf is experiencing pretty severe capacity drop after just a few years. Commercial vehicles have got to be conservative.
Posted by: Sean Prophet | 05 April 2014 at 02:10 PM
Tesla is using a similar SOC range as the LEAF, but they don't experience any severe capacity drop.
I rarely charge my LEAF above 80% and it still has lost a good chunk of capacity after 3 years in coastal southern California. Nissan's chemistry is just not up to dealing with warm temperatures, it seems to do much better in the Pacific NorthWest even when charging to 100% regularly.
Posted by: Dave R | 05 April 2014 at 11:12 PM
I don't think the longevity they're worried about, I think the issue is peak power draw on the battery cells vs. state-of-charge. If you look at a plot of battery voltage vs charge level, the voltage drops as the battery "empties". As voltage goes down, to draw the same power you need to draw more current. To keep current draw below a specified C level at the individual cell level, you'd need to add more cells in parallel.
For a large 16t vehicle, you'll need a lot of power to move that truck around. And therefore the pack needs to be able to generate a minimum amount of power, which may prevent it from discharging below 30-40%.
Posted by: Anthony F | 07 April 2014 at 10:49 AM