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PHEVs emit almost five times greater global warming pollution than lab-reported data show, according to a recent report.

Widening Gap In Official and Actual CO2 Output

Statistics reveals that PHEVs emit just 19% less CO₂ than conventional petrol and diesel vehicles, based on research carried out by a advocacy group. This contrasts significantly with lab estimates, which assumed a three-quarters reduction in emissions.

Analysts examined information from in-vehicle energy use monitors of 800,000 vehicles registered in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official emissions are decreasing,” said a senior researcher participating in the report. “This gap is widening and creates a significant issue. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Primary Reasons Behind the Discrepancy

Analysts attributed most of the difference to overestimates of the “utility factor” – the percentage of miles travelled in electric power compared to overall mileage. The team found that only a quarter of driving was done in EV mode, whereas official assumptions suggested 84%.

Even, when running in EV mode, emission levels were significantly higher than lab estimates. This happened because electric motors were insufficiently powerful sufficient to function independently, resulting to combustion motors burning gasoline for nearly a third of the distance completed in EV mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV CO2 output enabled four large automaker groups to avoid more than €5bn in fines from 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs would pay about €500 extra annually in running costs than is assumed under lab tests.

“The bold claims that automakers often promote about their PHEV vehicles are clearly far from the truth,” commented a transport analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the planet and cutting money. Actually, PHEVs are only slightly improved than regular gas and diesel vehicles in terms of fuel use, CO₂ production, and running costs.”

Political Debate and Automotive Lobbying

Hybrid cars have lately been brought again into policy debates as carmakers have lobbied the EU to weaken CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from member states with large car manufacturing.

Some high-level politicians have proposed PHEVs as a potential “flexibility” solution to introduce in the regulation.

An independent energy policy specialist, who was not involved with the research, called the analysis a “very useful contribution” after years in which parts of the car sector claimed there was too little information to accurately assess actual CO2 output.

“The results demonstrate, without question, that the gap in official and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or diesel vehicles,” the expert said. “Any regulatory changes concerning PHEVs should be implemented with utmost care and considering that evidence.”