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Plug-in hybrid electric vehicles release almost 5x more planet-heating pollution than lab-reported figures show, as per a recent report.

Widening Discrepancy In Official and Real-World CO2 Output

Statistics shows that PHEVs release just one-fifth less CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy group. This contrasts significantly with laboratory tests, which assumed a 75% decrease in emissions.

Researchers studied information from onboard energy use monitors of eight hundred thousand cars sold in the EU between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” said a senior analyst involved in the report. “That discrepancy is widening and poses a serious issue. As a result, PHEVs pollute nearly as much as petrol cars.”

Key Reasons Behind the Emissions Gap

Analysts linked the majority of the difference to overestimates of the “electric driving share” – the ratio of miles driven in electric power compared to overall distance. They found that just 27% of driving was completed in electric mode, whereas official estimates suggested 84%.

Additionally, when operating in electric mode, pollution levels were well above official projections. That happened because EV motors were insufficiently powerful sufficient to operate independently, resulting to combustion motors using fossil fuels for almost one-third of the travel covered in EV mode.

Regulatory and Financial Consequences

Based on estimates, the underestimation of PHEV emissions allowed several large automaker companies to escape more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend about €500 extra annually in running expenses than is estimated under laboratory tests.

“The bold statements that automakers often promote about their PHEV cars are clearly way off the truth,” stated a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of energy use, CO₂ emissions, and running expenses.”

Political Debate and Automotive Pressure

Hybrid vehicles have lately been drawn again into policy discussions as automakers have lobbied the EU to weaken CO₂ standards. A planned prohibition on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and opposition from member states with large automotive industries.

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

One independent energy policy expert, who was unaffiliated with the study, described the report a “very useful contribution” after a long period in which parts of the car sector claimed there was insufficient data to properly assess actual CO2 output.

“The results show, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or conventional vehicles,” they stated. “Any regulatory adjustments regarding PHEVs should be made with extreme care and considering this data.”