Plug-in hybrid cars with zero emission driving modes are 'conning' buyers, review of best-selling models by a green transport group finds

Plug-in hybrid cars are not as good for the environment as manufacturers claim because they can’t operate in electric-only mode if it’s cold, the vehicle has been put in cruise control or the electric motors can’t generate enough power.

That’s according to a green transport campaign, which highlighted the limitations of hybrid vehicles as part of a market review.

Greg Archer from Transport & Environment said one leading carmaker ‘is conning its customers’ with claims of green grandeur.   

Plug-in hybrid problems: A new report has found that plug-in hybrid models don’t maximise the use of their electric power, especially when it’s cold

When ministers announced earlier this year that the ban on the sale of new petrol and diesel cars would not only be fast-tracked by five years to 2035 but also include hybrid and plug-in hybrid cars, there was uproar from the motor industry and some owners.  

Hybrids are seen by many as a stepping stone between the switch from cars with internal combustion engines and future vehicles expected to be powered by electricity.

Plenty of brands – especially the likes of Toyota, Lexus and Mitsubishi – have invested millions in the development of these vehicles as a result. 

Because these cars can switch between battery electric power and an internal combustion engine, manufacturers claim they will deliver significant emissions and fuel economy improvements over traditional cars.

However, all models have claimed economy figures that, in real world driving, are simply not achievable.

For instance, the UK’s best-selling plug-in hybrid model, the Mitsubishi Outlander PHEV, has a claimed combined fuel economy of 139 miles and a quoted range of 28-mile range in electric mode only.

These figures are based on laboratory test cycles and are almost impossible to replicate on the road. 

Environmental campaigners have concerns that these heavily advertised figures – which are used online and in TV adverts promoting the vehicles – are misrepresentative, as highlighted by a new market review.

The Guardian reports that many popular plug-in hybrids don’t maximise the use of green electric power due to limitations with the technology.

It reviewed models that feature zero-emission driving modes, which when selected are designed for the vehicle to operate only using electric power without switched to the supplementary petrol engine. 

Plug-in hybrid cars with zero emission driving modes are 'conning' buyers, review of best-selling models by a green transport group finds

The report by The Guardian and Transport & Environment found that the Volvo XC90 Twin Engine plug-in hybrid switches to the petrol engine if the cabin heating is switched on

Plug-in hybrid cars with zero emission driving modes are 'conning' buyers, review of best-selling models by a green transport group finds

Range Rover’s p400e (pictured) will use its petrol internal combustion engines if more power is required than the electric supply can provide

The report found that many of these modes switch off if the conditions are not suitable for the vehicle or technology. 

One of the biggest issues is cold weather, something that has greater significance in Britain at this time of year. 

Popular models have been found to deviate from using their electric-only modes to  the petrol engine when temperatures drop, even when the onboard battery is fully charged.

This is partly because the batteries need to warm up in order for them to send power to the electric motors.

And when users choose to turn on the cabin heating, this can also trigger plug-in vehicles to switch to their internal combustion engines.

This is the case for models such as the Volvo XC90 Twin Engine, Mercedes-Benz E300 and Kia Niro Plug-In Hybrid, the report states.

The latter also switches to petrol power when the windscreen de-mister is switched on, according to Transport & Environment. 

Range Rover’s p400e and Porsche’s Cayenne E-Hybrid were also found to use their petrol internal combustion engines if more power is required than the electric-only supply can provide.

Specific electric driving modes in BMW’s range of plug-in hybrids – including the Mini Countryman Plug-in Hybrid –  also have speed limits.

When these are reached, the power switches from electricity to petrol. 

The market-wide review also found that Mitsubishi’s Outlander would instantly revert to the petrol engine when a driver uses adaptive cruise control or if the battery gets too hot or too cold in extreme conditions. 

A spokesman for Mitsubishi responded to The Guardian’s report, stating: ‘The vast majority of owners we surveyed use their Outlander [plug-in hybrid] as it was engineered and are enjoying a lower carbon footprint and lower running costs as a result.’

Plug-in hybrid cars with zero emission driving modes are 'conning' buyers, review of best-selling models by a green transport group finds

Some 34,734 plug-in hybrid cars were registered in the UK in 2019, down almost 18% on the year previous due to the government’s decision to remove a GBP2,500 grant for them 

Plug-in hybrid cars with zero emission driving modes are 'conning' buyers, review of best-selling models by a green transport group finds

Review also found that the Mitsubishi’s Outlander PHEV instantly reverts to the petrol engine when a driver uses adaptive cruise control or if the battery gets too hot or too cold

Plug-in hybrid cars with zero emission driving modes are 'conning' buyers, review of best-selling models by a green transport group finds

The Mini Countryman Plug-in Hybrid can only use a pure electric mode up to a set speed before having to switch to its supplementary petrol engine

Greg Archer, UK director at Transport & Environment, said one leading carmaker – which he didn’t reveal – ‘is conning its customers’, after it had been contacted by an unhappy owner of one of its plug-in hybrid. 

He has backed the UK government’s decision to ban the sale of all hybrid cars in-line with new petrol and diesels from 2035 and also the removal of grants to help drivers purchase them at reduced rates.

In October 2018, ministers announced they were removing a GBP2,500 plug-in car grant for hybrids because they had seen significant evidence that users – especially those who had bought hybrid cars for businesses to benefit from lower tax rates – do not charge the vehicles as often as they should, meaning they are used in an uneconomical way.  

Plug-in hybrid cars with zero emission driving modes are 'conning' buyers, review of best-selling models by a green transport group finds

He told The Guardian: ‘A [plug-in hybrid] is not driving with zero emissions if it switches on its engine when the driver de-mists the windscreen. 

‘This is another example of carmakers attempting to mislead their customers about the real emissions from their car.’  

Some 34,734 plug-in hybrid cars were registered in the UK in 2019, down almost 18 per cent on the year previous.

This was mainly due to the removal of the GBP2,500 plug-in grant towards the purchase of this type of vehicles.

As a result, sales of pure electric models – those that use battery power only – overtook PHEVs for the first year on record.

In fact, uptake of battery electric and standard (non-plug-in) hybrids were both up by 144 per cent and 17 per cent respectively in 2019, figures from the Society of Motor Manufacturers and Traders shows.

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