Car makers favour plug-in hybrids and have invested heavily in the technology over the past few years. But there's a problem…
On paper a plug-in hybrid electric vehicle, or PHEV, offers an ideal solution: enough electric range for short journeys and many commutes but with petrol- or diesel-engine back-up that means range anxiety isn’t an issue, so the car can still be used for much longer journeys. PHEVs’ emission-free capability means they perform impressively well in economy testing, both to NEDC and WLTP standards, and their low official CO2 emissions are good for the car makers’ fleet-average figures, good for company car drivers and, in theory, good for the environment.
The PHEV powertrain, however, is complex and the driver must both understand the technology and work with the vehicle in order to maximise its efficiency and electric range – the car won’t do the work for them. Journeys, and subsequent journeys, need to be planned in advance and the driver will often be required to switch between driving modes and power sources while on the move to get the best out of the vehicle.
Electric ranges are relatively short, meanwhile, and the driver will need to exercise restraint in order to make the most of what emission-free running is available. And because its electric range is so short, a PHEV needs to be plugged in if not after every journey, then certainly after most of them. If that isn't practical or convenient – for example, if the car can't be charged at home – then a PHEV isn't going to be the best choice of vehicle.
As a result PHEVs have come in for some bad press. Over the past few years it has been widely recognised across the fleet industry that PHEVs have been routinely ‘misused’. This misuse, either wilful or through a lack of understanding, has resulted in real-world fuel economy figures that fall far short of manufacturers’ claims. In 2017 fleet data consultancy TMC reported that PHEVs were among the ‘highest polluting’ company cars. TMC also found that some drivers never charged their car at all and relied on the petrol engine alone.
By giving drivers a better understanding of how a PHEV works, we can help them decide whether or not it’s the right powertrain for them and equip them with the skills to maximise its electric range and efficiency once they’re behind the wheel.