Plug-in Hybrid Vehicles Emit Almost as Much as Petrol Vehicles, Report Reveals

Plug-in hybrid cars release almost 5x more planet-heating pollution than lab-reported figures show, according to a recent analysis.

Growing Discrepancy In Lab and Actual Emissions

Statistics shows that PHEVs release only 19% less CO₂ than conventional petrol and diesel vehicles, according to analysis carried out by a advocacy organization. That contrasts sharply with lab estimates, which assumed a three-quarters reduction in emissions.

Researchers examined data from onboard fuel consumption meters of eight hundred thousand cars sold in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” said a lead analyst involved in the report. “That discrepancy is growing and poses a serious issue. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Key Factors Driving the Discrepancy

Analysts attributed most of the gap to overestimates of the “electric driving share” – the percentage of miles travelled in electric power compared to total mileage. They found that only 27% of travel was done in EV mode, whereas official assumptions suggested 84%.

Even, when operating in EV mode, emission amounts were significantly higher than lab projections. This happened because EV motors were not strong sufficient to operate independently, leading to combustion motors using gasoline for almost one-third of the distance completed in electric mode.

Regulatory and Financial Implications

According to calculations, the underestimation of PHEV CO2 output enabled several large carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 extra per year in running expenses than is assumed under laboratory tests.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are clearly far from the truth,” commented a automotive analyst. “Consumers are being misled into believing that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are little better than regular petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid cars have lately been brought back into political discussions as carmakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and opposition from EU countries with significant car industries.

Several high-level officials have suggested PHEVs as a possible “compromise” option to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, described the analysis a “very useful addition” after a long period in which parts of the automotive sector argued there was too little information to accurately evaluate real-world CO2 output.

“These findings demonstrate, without question, that the gap in lab and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel cars,” they stated. “Any regulatory changes concerning PHEVs should be implemented with extreme caution and in the light of this data.”