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PHEVs release nearly 5x more planet-heating emissions than lab-reported data indicate, as per a recent analysis.

Widening Gap Between Official and Real-World Emissions

Data shows that PHEVs emit only 19% lower CO₂ than traditional petrol and diesel cars, according to research conducted by a non-profit group. This differs sharply with lab tests, which suggested a 75% reduction in emissions.

Analysts studied information from onboard fuel consumption meters of eight hundred thousand vehicles registered in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while official figures are decreasing,” said a senior analyst involved in the report. “This discrepancy is growing and poses a significant issue. As a result, PHEVs emit nearly as heavily as gasoline cars.”

Primary Factors Behind the Emissions Gap

Researchers attributed most of the difference to overestimates of the “electric driving share” – the ratio of miles driven in battery mode compared to total mileage. They found that only 27% of driving was completed in electric mode, while official estimates suggested over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than official estimates. That happened because electric motors were not strong enough to function independently, leading to engines using gasoline for almost a third of the travel covered in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV emissions allowed four major automaker companies to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs would spend approximately €500 extra annually in running costs than is assumed under laboratory conditions.

“The strong statements that automakers like to make about their PHEV cars are obviously far from the mark,” stated a automotive analyst. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are little improved than standard gas and diesel cars in terms of energy use, CO₂ emissions, and operating costs.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have recently been brought again into political debates as automakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on sales of new combustion engine vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with large car industries.

Several high-level politicians have proposed PHEVs as a possible “compromise” option to include in the regulation.

An external energy policy specialist, who was not involved with the research, called the report a “very useful addition” after a long period in which parts of the car sector claimed there was insufficient information to accurately evaluate 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 utmost care and considering this data.”