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Plug-in hybrid electric vehicles produce almost 5x greater planet-heating emissions than official data show, as per a recent analysis.

Widening Discrepancy In Official and Real-World CO2 Output

Statistics reveals that PHEVs release just one-fifth less CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy organization. That differs significantly with lab estimates, which suggested a three-quarters decrease in emissions.

Analysts examined data from onboard energy use monitors of 800,000 cars registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, up from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” said a senior analyst involved in the report. “That gap is widening and creates a serious issue. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Key Reasons Behind the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in battery power relative to total distance. The team determined that only 27% of driving was completed in EV mode, while official estimates suggested over four-fifths.

Additionally, when running in EV mode, pollution amounts were significantly higher than official estimates. That occurred because EV motors were not strong sufficient to operate alone, leading to engines burning gasoline for nearly a third of the distance completed in electric mode.

Policy and Economic Implications

According to estimates, the underestimation of PHEV emissions allowed several major automaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs could spend about €500 more annually in running costs than would be assumed under lab tests.

“The strong claims that automakers like to make about their PHEV cars are obviously far from the mark,” stated a automotive analyst. “Buyers are being misled into thinking that by buying a PHEV, they are helping the environment and saving costs. In reality, PHEVs are little improved than standard gas and diesel cars in terms of energy consumption, CO₂ production, and running costs.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been drawn back into policy debates as automakers have pressed the EU to relax CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car sector and resistance from EU countries with large car manufacturing.

Some senior officials have proposed PHEVs as a potential “compromise” solution to include in the legislation.

An external energy policy specialist, who was not involved with the study, called the analysis a “very useful addition” after a long period in which segments of the car industry argued there was insufficient information to accurately assess actual emissions.

“These findings demonstrate, beyond any doubt, that the difference in official and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional cars,” they stated. “Any policy changes concerning PHEVs should be implemented with utmost caution and considering that data.”