Plug in Hybrid Cars Emit Almost as Heavily as Petrol Vehicles, Report Finds

Plug-in hybrid cars produce almost five times greater planet-heating emissions than official data indicate, according to a recent analysis.

Widening Gap In Official and Actual Emissions

Statistics shows that PHEVs release just 19% lower CO₂ than traditional gas and diesel cars, according to research conducted by a advocacy group. This contrasts significantly with lab estimates, which assumed a 75% decrease in emissions.

Researchers studied information from onboard energy use meters of eight hundred thousand cars sold in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, up from three and a half times in 2021.

“Real-world CO2 output are rising, while official emissions are falling,” said a senior researcher involved in the report. “This discrepancy is widening and creates a significant problem. As a result, PHEVs pollute nearly as much as gasoline cars.”

Primary Reasons Behind the Discrepancy

Researchers attributed the majority of the difference to overestimates of the “utility factor” – the percentage of miles travelled in battery power compared to overall mileage. They determined that only 27% of driving was completed in EV mode, whereas lab assumptions suggested 84%.

Additionally, when operating in EV mode, pollution amounts were significantly higher than lab projections. This happened because electric motors were insufficiently powerful sufficient to function independently, leading to engines burning fossil fuels for nearly a third of the distance covered in electric mode.

Regulatory and Economic Implications

According to calculations, the underestimation of PHEV emissions allowed several major automaker groups to avoid more than €5bn in fines from 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs could spend about €500 extra per year in running expenses than would be assumed under laboratory conditions.

“The bold claims that manufacturers like to make about their PHEV cars are obviously far from the truth,” stated a automotive expert. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are little better than regular petrol and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Debate and Automotive Pressure

Plug-in hybrid vehicles have lately been brought back into political debates as automakers have pressed the European Union to relax CO₂ standards. A proposed ban on sales of new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and opposition from member states with large automotive manufacturing.

Several senior politicians have proposed plug-in hybrids as a potential “flexibility” option to introduce in the legislation.

An external energy economics specialist, who was not involved with the study, described the analysis a “highly valuable contribution” after years in which parts of the car sector argued there was insufficient data to accurately assess actual CO2 output.

“The results show, beyond any doubt, that the difference between lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel vehicles,” they said. “Any policy adjustments regarding PHEVs should be made with extreme care and considering that evidence.”