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PHEVs release nearly five times greater planet-heating emissions than official data indicate, as per a new report.

Widening Discrepancy Between Official and Real-World CO2 Output

Statistics shows that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel cars, based on analysis conducted by a advocacy organization. That differs significantly with laboratory tests, which suggested a 75% decrease in emissions.

Researchers studied information from onboard fuel consumption monitors of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” stated a senior researcher participating in the study. “This gap is growing and creates a significant issue. Consequently, PHEVs emit almost as much as petrol vehicles.”

Key Reasons Driving the Discrepancy

Researchers attributed most of the gap to overestimates of the “electric driving share” – the ratio of kilometers travelled in battery power compared to overall mileage. They determined that only 27% of driving was completed in electric mode, whereas official assumptions suggested over four-fifths.

Even, when running in EV mode, emission levels were well above official estimates. This occurred because EV motors were insufficiently powerful sufficient to operate alone, leading to combustion motors using gasoline for nearly one-third of the distance covered in EV mode.

Regulatory and Financial Implications

According to estimates, the underestimation of PHEV CO2 output enabled four major carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ standards.

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

“The strong claims that automakers like to make about their PHEV cars are clearly far from the mark,” commented a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are helping the planet and cutting money. In reality, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Debate and Automotive Pressure

Hybrid vehicles have lately been brought back into policy discussions as carmakers have pressed the EU to relax CO₂ targets. A proposed prohibition on new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and opposition from EU countries with large automotive manufacturing.

Several high-level officials have proposed plug-in hybrids as a possible “flexibility” option to introduce in the legislation.

An external energy policy expert, who was not involved with the research, called the analysis a “highly valuable contribution” after a long period in which segments of the car sector claimed there was insufficient information to accurately evaluate actual CO2 output.

“These findings show, without question, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional cars,” they stated. “All policy changes regarding PHEVs should be implemented with utmost caution and in the light of that evidence.”