Plug-in Hybrid electric Cars Pollute Almost as Much as Petrol Cars, Study Reveals

PHEVs release almost five times greater global warming pollution than lab-reported figures show, as per a recent analysis.

Widening Discrepancy In Lab and Real-World Emissions

Statistics reveals that PHEVs emit only 19% less CO₂ than conventional gas and diesel vehicles, based on research conducted by a non-profit group. This contrasts significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Analysts examined data from onboard energy use monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” said a lead researcher involved in the study. “This discrepancy is growing and poses a serious problem. Consequently, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Factors Behind the Emissions Gap

Analysts attributed the majority of the difference to inflated estimates of the “electric driving share” – the ratio of kilometers travelled in battery mode compared to overall mileage. The team determined that only 27% of driving was done in EV mode, while official estimates suggested over four-fifths.

Additionally, when running in electric mode, emission levels were well above lab projections. That occurred because electric motors were not strong sufficient to operate independently, leading to engines burning fossil fuels for nearly a third of the distance completed in electric mode.

Policy and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output enabled several large carmaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs could pay approximately €500 more annually in running expenses than would be assumed under laboratory tests.

“The bold claims that manufacturers often promote about their PHEV cars are clearly way off the truth,” commented a transport analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and running costs.”

Policy Discussion and Industry Lobbying

Hybrid cars have recently been drawn back into policy debates as carmakers have lobbied the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and opposition from EU countries with significant car industries.

Several high-level officials have suggested plug-in hybrids as a potential “compromise” option to introduce in the legislation.

One independent energy policy specialist, who was not involved with the study, called the report a “very useful contribution” after years in which parts of the car sector claimed there was too little information to properly assess real-world CO2 output.

“The results demonstrate, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” the expert stated. “Any regulatory changes concerning PHEVs should be made with utmost care and in the light of that data.”