Last reviewed 30 April 2021
As petrol and diesel cars and vans are phased out, with a ban on new sales from 2030, operators of small goods vehicles will have to switch to alternatives and battery electric vehicles (BEVs) seem to be the preferred current choice as a replacement. It is not yet certain whether BEVs are the best option but there are some aspects of the data that operators should be aware of. Certainly, the future for heavy vehicles is unclear but battery-operated versions are already available and more restrictions on diesel operation are likely.
In this article Richard Smith looks at the suitability of battery vehicles for goods transport and examines some of the issues that operators will need to consider when planning a switch to them.
The suitability of BEVs for road transport
It is likely to be the case, even in the longer term, that there are some applications for which battery operation is not suitable: heavy agricultural and construction vehicles and any other sustained off-road use, for example, will exhaust the battery power too quickly to be viable. Their use in critical applications that need continuous and instant availability and indeterminate duration of operation, especially when additional equipment needs to be operated for an extended period, might not be safe without massive over-provision. For smaller vehicles, though, especially those that run over shorter distances between returns to the depot, battery electric traction is now feasible.
One of the central problems with assessing the potential of BEVs is that there is as yet little actual experience with operating significant numbers of them for the whole range of applications. Certainly, a number of BEVs are already in use and performing satisfactorily but these are most commonly being used in areas where their strengths lie, ie for short journeys by light vehicles with ample opportunities for recharging. There is not so much experience, however, of continuous operation over long distances with fewer opportunities for recharging or with heavier vehicles on critical operations. Much of the detail in terms of operating BEVs in these circumstances is theoretical and therefore no catalogue of experience exists to inform decisions.
The limitation of range
The principal feature of battery vehicles that is given as a major limitation is “range anxiety”. In the car sector, BEVs have become a much more realistic proposition in terms of range, with figures in some cases now comparable to the range of petrol and diesel engines. Vans generally have lower figures quoted, ranging between 70 and 125 miles in most cases, although 205 miles is quoted in one case. However, as is the case with petrol and diesel vehicles the figures are obtained from the WLTP type approval test conducted under closely defined circumstances (to provide a true comparison) that may not resemble a real-life situation. Consumption is measured in kilowatt-hours per 100km rather than litres but still enables a range to be calculated. So as with petrol and diesel, while the WLTP may be relied on for its intended purpose, to tell us whether the power consumption of vehicle A is greater or less than that of vehicle B, it cannot be relied on to tell us what the range will actually be and gaining further experience is therefore vital.
The factors that determine the range of BEVs are mostly the same as those that apply to petrol and diesel vehicles. Weight is one key variable and the greater the weight, the lower the range, so this will affect goods vehicles more than cars. Speed is another key factor, and while speed can be reduced to increase range, it could mean that drivers run out of time before vehicles run out of power. The effect of weight and speed on range can at least be quantified to a large extent but a factor that is less easy to predict is individual driving style.
Ambient temperature also affects the performance of internal combustion engines but not by a significant amount under normal circumstances, whereas for BEVs it has a substantial effect on range. The range of a BEV at -5℃ could be reduced by 40-45% compared with the range at 20℃. Additionally, in terms of energy consumption, the range of a BEV will be affected by how much load is placed on the battery by non-traction ancillaries. Whilst the cab heater in an internal combustion engine is then effectively a by-product of waste heat that must be removed from the engine to stop it overheating, with a BEV any energy used to warm the cab means less to move the vehicle. In the case of other seat, steering wheel and screen heaters, as with LED lights, these certainly use less power but in all cases there will be some drain on the battery and other uses like refrigerator units or crane jibs will also reduce range if not powered by a separate battery or unless a small petrol/diesel auxiliary power unit is permitted.
Another important consideration to take into account is that best-case range figures are usually quoted from 100% to 0% charge, but to prolong the life of the batteries used (as with other batteries) battery management systems may limit the charging to 80%, certainly in the case of high-power fast charging. Likewise, the minimum charge should not drop below 20% and, in any case, once the charge goes below a certain level it tends to deplete quickly and in the event of running out of charge, the best option for an electric vehicle with a flat battery is recovery by low loader.
Taking all the above into account, it needs to be considered that real range figures may be less than those quoted by up to 20%.
The need to recharge
Whatever the power source, range is to a degree irrelevant if appropriate refuelling can be arranged. The range of a typical petrol or diesel van might be about 250 miles but range is largely irrelevant because, when the tank is nearly empty, the full range can be quickly recovered in about five minutes at a normal filling station pump. At the current time, the very best range found for a battery electric van was 205 miles, so roughly comparable to a petrol or diesel vehicle, but the recharge time is over 11 hours (0 to 100%) using a standard wall box. However, since it would not be sensible to let the battery charge go much below about 20%, we are perhaps talking about an effective range (from 100% to 20%) of approximately 160 miles for a fully charged battery and a refuelling time (20% to 100%) of something like nine hours to recover that 160-mile range. Such recharging is almost certainly going to have to be done at base because of the time involved.
On a rapid charger a 0 to 80% recharge time is quoted as 45 minutes, so 20% to 80% might take about 35 minutes to recover the same 160 miles maximum range or only about 130 miles if we don’t let the charge go below 20%. It must be stressed that all these figures are speculative as they assume that charge and discharge rates are linear, which they almost certainly are not, and they also ignore the effects of weight, speed, temperature and other variables on range. Nevertheless, they do give a rough comparison of the on-the-road/off-the-road ratio for the two types of vehicle.
A daily distance of 160 miles followed by an overnight charge of 11 hours may be fine for some short distance delivery operations where the vehicle returns to base at the end of the day. Alternatively, up to 160 miles in half a day, followed by a fast charge of 45 minutes (either back at base or at a public charger) while the driver takes a break, followed by up to another 160 miles to complete the working day might be a viable alternative.
Much money is also being spent on providing public charging points but another difficulty lies in the sheer number that will be required. If it takes five minutes to refuel a petrol or diesel vehicle then a single pump can serve 12 vehicles an hour but if it takes 45 minutes to refuel a single BEV then a single charging point can only serve one and one-third vehicles per hour, so about 10 charging points will be required to achieve the same total throughput as a single diesel pump.
Assessing the use of BEVs
BEVs are already a feasible alternative to petrol and diesel for many applications but when making replacement decisions operators will need to consider many more factors than those currently being advised in the headline specifications.
At this time, the issues of range and recharging have not been sufficiently scrutinised to give confidence that BEVs can yet provide an equivalent or feasible alternative to the current use of petrol and diesel vehicles in road haulage and the hope is that this data can be analysed and more rigorous testing provided where wholesale industry changes are being encouraged and, increasingly, expected.
See the topic Alternatively Fuelled Vehicles for more information on BEVs and other alternatives to petrol and diesel vehicles.