Carbon dioxide (CO2) emissions from plug-in hybrid vehicles (PHEV) are an average of two-and-a-half times higher than official tests indicate, environmental campaigners have warned.
Pressure groups Greenpeace and Transport & Environment claimed their analysis shows that a typical PHEV emits 117g of CO2 per kilometre, compared with the 44g suggested in laboratory examinations.
Campaigners believe this illustrates that the vehicles should not be exempt from a possible earlier ban on the sale of new petrol and diesel cars.
They are marketed as low-carbon alternatives, but environmentalists claim the limited electric range of the vehicles and owners not charging their batteries as often as possible increases their CO2 emissions.
The analysis is based on data from a variety of sources and represents around 20,000 PHEVs driven across Europe.
Transport Secretary Grant Shapps has indicated that a ban on sales of new petrol, diesel and hybrid cars and vans could be brought forward from 2040 in a bid to meet carbon reduction targets.
Greenpeace UK’s head of politics Rebecca Newsom said: “Plug-in hybrids are the car industry’s wolf in sheep’s clothing. They may seem a much more environmentally friendly choice but false claims of lower emissions are a ploy by car manufacturers to go on producing SUVs and petrol and diesel engines.
“It’s great that the Government is considering bringing the ban on new petrol and diesel vehicles forward to 2030, doing so is one of the most important things the Government can do now to help tackle the climate emergency.
“But ministers mustn’t be duped by plug-in hybrids when making this critical decision. It’s imperative that they are included in the 2030 ban, and that support is provided to enable workers to transition to electric vehicle manufacturing.”
Greg Archer, UK director of Transport & Environment, said: “PHEVs are not electric cars and claims that in cities plug-in hybrids have zero emissions are just mischievous, misleading marketing.
“Unless the battery is frequently charged, these fake electric cars are actually worse for the climate than conventional cars.”
Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders, acknowledged there are difference between lab tests and real-world use of cars.
But he accused the pressure groups of analysing figures that “government and industry abandoned two years ago” in favour of a “more robust” test.
He went on: “Even the report’s assumed figures show plug-in hybrid vehicles provide more than a 30% overall reduction in emissions compared to petrol or diesel.
“PHEVs also provide a flexibility few other technologies can yet match with extended range for longer, out of town journeys, and battery power in urban areas, reducing emissions and improving city air quality.
“PHEV range and performance will continue to improve meaning that, for many users, they are the essential stepping stone to a fully electric vehicle.”