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PHEVs emit nearly five times more planet-heating emissions than lab-reported data show, as per a new report.

Widening Discrepancy In Official and Real-World CO2 Output

Statistics shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel vehicles, according to analysis carried out by a advocacy group. That contrasts sharply with laboratory estimates, which suggested a 75% reduction in emissions.

Researchers studied information from onboard energy use monitors of eight hundred thousand cars sold in the EU from 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported emissions are decreasing,” said a lead researcher involved in the study. “That discrepancy is widening and poses a significant issue. As a result, PHEVs emit almost as much as gasoline cars.”

Key Reasons Behind the Discrepancy

Analysts linked most of the gap to overestimates of the “electric driving share” – the percentage of miles driven in battery mode relative to overall mileage. The team determined that only 27% of driving was done in electric mode, whereas official estimates assumed over four-fifths.

Additionally, when operating in EV mode, emission amounts were well above lab estimates. That occurred because electric motors were not strong sufficient to function alone, resulting to engines burning fossil fuels for almost a third of the distance completed in electric mode.

Policy and Financial Implications

According to estimates, the lowballing of PHEV CO2 output allowed several large carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 extra per year in operating expenses than is estimated under laboratory conditions.

“The strong claims that automakers often promote about their PHEV vehicles are obviously far from the mark,” commented a transport analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are little improved than regular petrol and diesel cars in terms of fuel consumption, CO₂ production, and running costs.”

Policy Debate and Industry Pressure

Hybrid cars have lately been brought back into political debates as automakers have lobbied the European Union to weaken CO₂ standards. A proposed prohibition on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive industry and opposition from member states with significant automotive manufacturing.

Several high-level politicians have proposed plug-in hybrids as a potential “compromise” option to include in the regulation.

An independent energy economics specialist, who was not involved with the study, called the report a “very useful contribution” after years in which parts of the car sector argued there was too little data to accurately assess actual emissions.

“These findings show, without question, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or conventional cars,” the expert said. “All regulatory adjustments concerning PHEVs should be implemented with extreme caution and in the light of that data.”