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Plug-in hybrid cars release almost five times more global warming emissions than lab-reported data indicate, according to a recent report.

Growing Discrepancy In Lab and Actual CO2 Output

Statistics reveals that PHEVs emit just 19% less CO₂ than conventional petrol and diesel cars, according to analysis carried out by a non-profit organization. That contrasts significantly with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts examined data from in-vehicle energy use meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from three and a half times in 2021.

“Actual emissions are rising, while official emissions are falling,” stated a lead analyst involved in the study. “This discrepancy is widening and poses a serious issue. As a result, PHEVs emit nearly as heavily as petrol cars.”

Primary Factors Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “electric driving share” – the percentage of miles travelled in electric power compared to overall mileage. They determined that only 27% of travel was completed in electric mode, while official assumptions suggested 84%.

Additionally, when operating in electric mode, emission levels were well above lab estimates. This happened because EV motors were insufficiently powerful enough to function alone, leading to combustion motors using gasoline for nearly a third of the distance covered in EV mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV CO2 output enabled four large carmaker companies to escape over €5bn in fines between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 extra per year in operating expenses than is estimated under lab conditions.

“The bold claims that automakers often promote about their plug-in hybrid vehicles are obviously way off the mark,” stated a automotive expert. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are only slightly better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and running expenses.”

Policy Debate and Industry Lobbying

Hybrid vehicles have lately been brought again into policy discussions as carmakers have lobbied the European Union to relax CO₂ standards. A planned prohibition on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the car sector and resistance from member states with large automotive manufacturing.

Some senior politicians have suggested plug-in hybrids as a potential “compromise” solution to include in the legislation.

An external energy economics expert, who was unaffiliated with the study, called the report a “very useful contribution” after a long period in which segments of the car industry argued there was too little data to properly evaluate real-world CO2 output.

“The results demonstrate, without question, that the difference between lab and real-world PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional cars,” they stated. “All policy changes concerning PHEVs should be made with extreme care and considering that data.”