Plug-in hybrids are a ‘wolf in sheep’s clothing’
According to new research, the carbon dioxide emissions of plug-in hybrid cars are up to two and a half times higher than official tests suggest.
Plug-in hybrid vehicles are powered by an electric motor that uses a battery that is recharged via the power outlet or via an onboard gasoline or diesel engine.
They account for 3% of new car sales.
But analyzes by lobbyists Transport and Environment and Greenpeace suggest they emit an average of 120g of CO2 per km.
This compares with 44 g per km in the official “laboratory” tests
Plug-in hybrid electric vehicles (PHEVs) are sold as a low-carbon alternative to traditional vehicles and conventional hybrids, which cannot be recharged from an external source, and are becoming increasingly popular.
The new research is published as the government considers whether to propose a ban on the sale of new gasoline, diesel and conventional hybrid cars from 2035 to 2030.
“Official” vs “real world”
The BBC understands that one suggestion is that plug-in hybrids should be given a hold on execution, with new sales allowed to continue through 2035.
This is because they can offer a range of 20 to 40 miles as purely electric vehicles and are therefore potentially significantly less polluting than other vehicles.
But this new analysis by Transport and Environment and Greenpeace suggests they offer nothing like the carbon savings claimed for them by manufacturers.
Official tests indicate that plug-in hybrids emit an average of 44g per km of CO2. These tests are conducted on a circuit and see vehicles being driven in a way that regulators consider “normal”.
The real figure, however, according to the report, is more like 120 g per km.
The advocacy groups have analyzed what they say is “real” fuel efficiency data collected from around 20,000 plug-in hybrid drivers across Europe.
These are drivers who have chosen to record their mileage and fuel consumption for surveys or who drive company or leased vehicles whose fuel efficiency is recorded.
According to this dataset, the lifetime emissions of a plug-in hybrid are on average around 28 tonnes of CO2.
In comparison, an average gasoline or diesel car is estimated to emit between 39 and 41 tons of CO2 from fuel over its life cycle, a conventional hybrid would typically emit more like 33 tons.
According to this data, a plug-in hybrid would only provide about a third of emissions reductions over a typical petrol or diesel car, much lower than official estimates.
The auto industry acknowledges that lab tests don’t always reflect real-world use, but criticized the report, saying it uses emissions data from a two-year test.
“PHEVs offer flexibility that few other technologies can yet match with extended range for longer, out-of-town trips and battery power in urban areas, reducing emissions and improving city air quality,” Mike Hawes , chief executive of the Society of Motor Manufacturers and Dealers told the BBC.
He says he expects range and performance to continue to improve, making them an “essential stepping stone to a fully electric vehicle.”
Greenpeace meanwhile describes PHEVs as “the wolf of the auto industry in sheep’s clothing”.
“They may seem like a much more environmentally friendly choice,” says Rebecca Newsom, head of policy at the pressure group, “but the false claims of lower emissions are a ruse by automakers to continue producing SUVs and petrol engines. and diesel “.
Transport and Environment’s analysis says a key problem with plug-in hybrids is that so many owners rarely actually charge their cars, which means they rely on the petrol or diesel engine.
Another is that many plug-in hybrid models include design features that automatically turn on the gasoline / diesel engine when starting on a cold day, or that crank that engine if the driver accelerates hard.
The latter mode means that the car’s emissions will greatly depend on the driver’s behavior.
“If you charge the battery all the time and tend to take a lot of short trips, they will have very low emissions,” says Nick Molden, who manages Emissions Analytics, a company specializing in vehicle emissions assessment.
“If you never charge the battery and drive very aggressively, the emissions can be significantly higher than the equivalent petrol or diesel model,” he continues.