🔗 Share this article

Plug-in hybrid cars release nearly 5x greater global warming emissions than official data show, according to a new report.

Growing Gap In Lab and Actual CO2 Output

Data reveals that PHEVs emit only 19% less CO₂ than conventional petrol and diesel cars, based on research carried out by a advocacy organization. This contrasts sharply with laboratory tests, which assumed a three-quarters decrease in pollution.

Analysts studied data from onboard energy use monitors of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while official figures are decreasing,” stated a senior researcher involved in the report. “This gap is widening and creates a serious problem. As a result, PHEVs emit almost as heavily as petrol cars.”

Primary Reasons Driving the Emissions Gap

Analysts linked the majority of the difference to overestimates of the “utility factor” – the ratio of miles travelled in electric power relative to total mileage. They determined that only 27% of travel was done in electric mode, while lab estimates suggested over four-fifths.

Even, when operating in electric mode, pollution levels were significantly higher than official estimates. This occurred because electric motors were not strong enough to function alone, leading to combustion motors using gasoline for almost a third of the distance covered in EV mode.

Regulatory and Economic Implications

Based on calculations, the underestimation of PHEV emissions allowed several large carmaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 extra per year in running costs than is assumed under laboratory conditions.

“The bold claims that automakers like to make about their plug-in hybrid vehicles are obviously way off the truth,” commented a automotive analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and running expenses.”

Policy Debate and Industry Pressure

Plug-in hybrid vehicles have recently been brought back into political debates as carmakers have lobbied the EU to weaken CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and opposition from EU countries with significant automotive industries.

Several senior officials have proposed plug-in hybrids as a possible “flexibility” solution to introduce in the legislation.

An independent energy policy expert, who was not involved with the research, called the analysis a “highly valuable addition” after years in which parts of the car industry claimed there was insufficient information to accurately evaluate real-world emissions.

“The results demonstrate, beyond any doubt, that the difference in lab and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or diesel cars,” they said. “Any policy changes regarding PHEVs should be implemented with utmost caution and in the light of that evidence.”