Carbon dioxide emissions from the latest plug-in hybrid vehicles are three times higher than expected when their batteries are fully charged, a green transport think tank warned today.
Transport & Environment said while plug-in hybrids, known as PHEVs, are being touted as a climate solution and a stepping stone to full electrification, tests conducted in partnership with the University of Graz in Austria show that the most newer ones “pollute much more than claimed on suburban journeys”.
Additional pollution measurements taken on three of the latest PHEVs revealed that they can emit up to seven times their advertised carbon dioxide emissions during a typical journey through city centers when their batteries are flat.
The environmental group has called on the UK government to stop giving green tax breaks to PHEVs and ban the sale of new models as conventional petrol and diesel cars are pulled from showrooms in 2030.
Not as green as they say: New report claims plug-in hybrid cars ‘pollute far more than advertised’ and should be banned from sale with petrols and diesels in 2030
Two years ago, T&E discovered that PHEVs – which combine a small battery and electric motors with a combustion engine, usually a gasoline one – pollute far more than advertised on longer journeys.
However, its latest review found that they fall short of their ‘official’ emissions targets when driven in cities when motorists use them to get to work.
The results are based on measurements taken from three recent PHEV models: a BMW 3 Series 330e xDrive (from £46,430 in the UK); Peugeot 308 Hybrid 225 (from £41,140); and Renault Megane E-TECH Plug-in Hybrid 160 (not sold in UK).
He found that the trio emitted more CO2 than advertised when tested on the road, even when starting with a full battery.
The BMW polluted three times its official rating when driven on a typical suburban route, according to tests by Graz University of Technology.
The Peugeot 308 and Renault Megane plug-in hybrids performed better, but still polluted 20% and 70% more than expected, respectively, despite the relatively short 34-mile round trip in the test.
The BMW tested in the Graz University of Technology report was a 330e xDrive, which costs in the UK from £46,430.
The Austrian university used emissions measurement technology on all three cars while driving them on designated suburban and city routes. The image shows the Peugeot with the pollution measuring equipment attached
Even with a fully charged battery, the BMW emitted three times the amount of CO2 advertised as producing, according to the report.
The study also measured the electric autonomy of each car.
In city driving, the Peugeot had just over half (53%) the advertised electric range on a single charge, while the BMW had just 74%.
Only the Renault had claimed the electric range, which is 31 miles on a full charge – which T&E says may not be enough for many commuters to make a round trip to work.
Transport & Environment said PHEVs are being misrepresented as a climate solution and a stepping stone to full electrification
Tested with an empty battery, BMWs, Peugeots and Renaults emitted between five and seven times their claimed CO2 on the road, as shown in this chart
As the UK government prepares to ban the sale of new petrol and diesel cars from 2030, some plug-in hybrids will be allowed to remain in showrooms until 2035.
Ministers have said only hybrids capable of ‘traveling a significant distance without emitting carbon’ will remain on sale until the middle of the next decade, although they have still not specified what ‘significant distance’ is. “.
After finding that PHEVs emit more on the road than advertised, the think tank says only plug-in hybrids with a minimum electric range of 80 miles and fast-charging capability should continue to be allowed to be sold until 2035.
Richard Hebditch, director of Transport & Environment UK, said: “Plug-in hybrids are being sold to drivers and governments as part of the climate fix. The truth is that they pollute far more than advertised and are a dangerous distraction from full electrification.
“In tests in town and on public transport, they pollute much more than announced.
“Government plans to decarbonise driving must be based on the reality of their emissions, not industry claims.”
Around half of all new PHEVs registered in the UK each year are currently company cars, as drivers can benefit from reduced taxation. T&E says it shouldn’t be
Some 101,414 plug-in hybrid cars were registered in Britain in 2022 – and a further 9,109 last month, according to the latest SMMT figures released this week.
However, company cars account for half (51%) of new PHEV registrations in the UK.
This is mainly due to lower taxation of in-kind benefits for employees and lower excise duties on vehicles compared to full-combustion engines.
But T&E adds that research shows that company car PHEVs travel the vast majority of miles with the engine running and are rarely charged by their keepers.
Tested with an empty battery, the BMW, Peugeot and Renault emitted between five and seven times their claimed CO2 on the road.
T&E said the government should tax passenger cars and PHEV company cars based on their real-world pollution.
Mr Hebditch added: “The UK has publicly committed to phasing out sales of new petrol and diesel cars by 2030, but has left a back door to fossil fuels in plug-in hybrids.
“The reality is that PHEVs are still big polluters.
“Unless there are strict rules on what will be eligible, we risk locking in CO2 from cars through the 2030s rather than the all-electric future we need.”
Smart technology or a bit stupid? Hybrid BMWs are said to be able to detect when they enter a low-emissions zone – like London’s ULEZ – and switch off their combustion engines. But T&E said that wasn’t always the case when it tested a BMW PHEV in Graz
London – which has the ULEZ – and Birmingham – where there is a Clean Air Zone – are among the cities chosen to pioneer BMW’s zero-emissions technology which is now fitted to its most popular plug-in hybrid vehicles
T&E tests BMW’s zero-emission geolocation tech – and finds it doesn’t work
German car giant BMW introduced geolocation technology in 2020 that automatically switches its PHEV models to zero-emission electric driving mode once they enter city limits.
However, when tested in Graz, the Series 3 PHEV used for the study ran its gasoline engine twice.
Tests also suggest that the BMW could save battery charge outside of cities when entering geo-fenced areas.
T&E said geolocation technology does not guarantee emission-free driving in cities and could potentially increase CO2 emissions outside those areas.
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