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PHEVs release nearly five times greater planet-heating pollution than lab-reported figures show, as per a recent report.

Widening Discrepancy In Official and Actual CO2 Output

Data shows that PHEVs release just 19% less CO₂ than traditional petrol and diesel cars, based on analysis carried out by a advocacy organization. That differs sharply with lab estimates, which suggested a three-quarters reduction in emissions.

Researchers examined information from onboard fuel consumption monitors of 800,000 cars sold in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” said a lead analyst participating in the report. “That gap is widening and creates a significant issue. Consequently, PHEVs emit almost as heavily as petrol cars.”

Primary Reasons Driving the Emissions Gap

Researchers linked most of the difference to overestimates of the “utility factor” – the ratio of miles driven in electric power compared to total distance. They determined that just 27% of driving was completed in electric mode, whereas lab estimates assumed over four-fifths.

Additionally, when operating in electric mode, pollution levels were well above official estimates. This occurred because EV motors were insufficiently powerful sufficient to function independently, leading to combustion motors using gasoline for almost one-third of the travel covered in EV mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV emissions allowed four large automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would spend approximately €500 more per year in running expenses than would be assumed under laboratory tests.

“The strong statements that automakers often promote about their plug-in hybrid cars are clearly way off the truth,” stated a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the environment and saving costs. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating costs.”

Policy Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought again into policy discussions as automakers have pressed the European Union to relax CO₂ standards. A planned ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the car industry and opposition from member states with significant car manufacturing.

Some high-level politicians have proposed plug-in hybrids as a possible “flexibility” option to include in the legislation.

An external energy policy expert, who was unaffiliated with the research, called the report a “very useful addition” after a long period in which segments of the automotive sector argued there was insufficient information to properly evaluate actual CO2 output.

“These findings demonstrate, beyond any doubt, that the difference between official and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” they stated. “All regulatory adjustments regarding PHEVs should be made with utmost caution and in the light of this evidence.”