New analysis from the consumer watchdog has revealed plug-in cars are on average 61 percent less fuel-efficient than what manufacturers claim. When averaged out over 9,000 miles, this could lead to drivers paying an average of £400 more per year on fuel costs in a devastating blow for cash-strapped motorists.
“It is clear that the standard set for calculating fuel efficiency rates is flawed and should be reviewed to reflect real-life driving conditions.
“This would ensure manufacturers advertise more accurate rates and consumers have an accurate understanding of how much they should expect to spend on fuel.”
Plug-in hybrid vehicles are seen as an intermediary stage between traditional petrol and diesel models and new electric vehicles.
They come fitted with a smaller battery and are topped up with traditional petrol or diesel.
But added the WLTP tests “consistently demonstrate” plug-in vehicles do offer comparable range with petrol and diesel vehicles.
He said: “By law, manufacturers are required to test all vehicles of all technologies to the same, repeatable standard – the WLTP Test, which is independently verified by government authorities and it is these results – and only these results – that manufacturers are required by law to publish within any advertising communications.
“There will, however, always be a difference between lab tests and real-world use.
“Fuel use will vary greatly depending on the type of journey made, the conditions, driving style, load and other factors which is why the WLTP test is a standardised test designed to overcome these variables and provide consumers with accurate and comparable results across all vehicles.
“The WLTP tests consistently demonstrate that plug-in hybrids (PHEVs) offer comparable range to pure petrol or diesel equivalents but deliver substantial emission reductions with zero-emission range typically 25-40 miles, which is more than ample given that 94 percent of UK car journeys are less than 25 miles.
“PHEV range and performance will continue to improve meaning that, for many drivers, they are the essential stepping-stone to a fully electric vehicle.”