Plug-in Hybrid Cars Emit Nearly as Much as Petrol Vehicles, Report Reveals
Plug-in hybrid cars release almost 5x more planet-heating pollution than lab-reported data show, according to a new analysis.
Widening Discrepancy In Lab and Actual CO2 Output
Statistics reveals that PHEVs emit just 19% less CO2 than traditional gas and diesel vehicles, according to analysis conducted by a non-profit group. That contrasts sharply with lab estimates, which assumed a three-quarters decrease in emissions.
Analysts examined information from in-vehicle fuel consumption meters of eight hundred thousand vehicles registered in Europe between 2021 and 2023. The team found that actual CO2 emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from three and a half times in 2021.
“Real-world emissions are increasing, while lab-reported figures are falling,” stated a senior researcher involved in the report. “That gap is widening and poses a significant issue. Consequently, PHEVs pollute nearly as heavily as petrol vehicles.”
Primary Factors Behind the Discrepancy
Analysts attributed most of the difference to overestimates of the “utility factor” – the ratio of miles travelled in battery power compared to total mileage. They found that only a quarter of driving was done in electric mode, while official assumptions suggested over four-fifths.
Additionally, when running in electric mode, pollution amounts were significantly higher than lab estimates. This occurred because EV motors were not strong sufficient to operate alone, leading to engines burning gasoline for nearly one-third of the travel covered in electric mode.
Regulatory and Economic Consequences
According to estimates, the lowballing of PHEV emissions enabled four major automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union average fleet CO2 targets.
Additionally, owners of PHEVs could spend approximately €500 extra per year in running costs than is assumed under lab tests.
“The strong claims that manufacturers often promote about their PHEV vehicles are clearly way off the mark,” stated a automotive analyst. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and saving costs. Actually, PHEVs are little better than standard gas and diesel vehicles in terms of energy use, CO2 emissions, and running costs.”
Policy Debate and Industry Pressure
Plug-in hybrid vehicles have recently been brought back into policy debates as automakers have pressed the EU to relax CO2 targets. A planned prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the car sector and resistance from EU countries with large car manufacturing.
Some senior politicians have proposed plug-in hybrids as a potential “compromise” solution to introduce in the legislation.
An independent energy economics specialist, who was unaffiliated with the research, called the report a “highly valuable addition” after a long period in which segments of the automotive industry claimed there was insufficient data to properly assess real-world CO2 output.
“The results demonstrate, beyond any doubt, that the difference in official and real-world PHEV fuel consumption and CO2 emissions is much, much greater than for petrol or conventional cars,” the expert stated. “Any regulatory adjustments concerning PHEVs should be implemented with utmost care and considering this evidence.”