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PHEVs release almost five times greater global warming pollution than official data show, according to a recent analysis.

Growing Gap Between Lab and Actual CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than conventional gas and diesel vehicles, according to analysis carried out by a advocacy organization. This contrasts sharply with lab estimates, which assumed a 75% decrease in emissions.

Analysts examined information from onboard fuel consumption monitors of eight hundred thousand vehicles sold in Europe from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are decreasing,” stated a senior analyst participating in the report. “This discrepancy is widening and poses a serious issue. As a result, PHEVs emit almost as heavily as petrol vehicles.”

Primary Factors Driving the Discrepancy

Researchers attributed the majority of the gap to overestimates of the “utility factor” – the percentage of miles travelled in electric mode relative to total mileage. They found that just a quarter of travel was completed in EV mode, while official estimates suggested 84%.

Additionally, when running in EV mode, emission amounts were significantly higher than official estimates. This occurred because electric motors were insufficiently powerful enough to operate alone, resulting to engines burning gasoline for nearly a third of the travel covered in EV mode.

Policy and Financial Implications

According to calculations, the lowballing of PHEV CO2 output enabled several large carmaker companies to escape over €5bn in penalties from 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ targets.

Additionally, owners of PHEVs would pay about €500 more annually in operating expenses than is estimated under lab conditions.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are clearly far from the mark,” commented a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly better than standard gas and diesel cars in terms of energy consumption, CO₂ production, and running expenses.”

Policy Discussion and Industry Lobbying

Hybrid cars have lately been brought again into political discussions as automakers have lobbied the EU to relax CO₂ standards. A planned ban on new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive industry and opposition from member states with large automotive industries.

Several senior officials have proposed plug-in hybrids as a potential “compromise” option to include in the regulation.

An external energy economics specialist, who was unaffiliated with the study, called the report a “very useful contribution” after years in which segments of the automotive industry claimed there was insufficient information to properly evaluate actual emissions.

“The results show, without question, that the difference between lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or diesel vehicles,” the expert stated. “Any regulatory adjustments regarding PHEVs should be made with extreme caution and in the light of that evidence.”