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Plug-in hybrid cars emit almost five times more planet-heating emissions than official figures indicate, as per a recent report.

Widening Gap In Official and Real-World CO2 Output

Data reveals that PHEVs emit just 19% lower CO₂ than traditional gas and diesel cars, according to research conducted by a non-profit group. This contrasts significantly with laboratory estimates, which assumed a 75% reduction in emissions.

Researchers examined data from onboard energy use monitors of eight hundred thousand vehicles sold in Europe between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are decreasing,” stated a lead researcher participating in the study. “That gap is growing and creates a serious issue. As a result, PHEVs pollute almost as much as gasoline cars.”

Key Factors Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of kilometers travelled in electric mode relative to overall mileage. The team found that just 27% of travel was completed in EV mode, whereas official assumptions suggested 84%.

Additionally, when operating in electric mode, pollution amounts were well above official projections. This occurred because EV motors were not strong enough to function independently, resulting to engines burning fossil fuels for nearly a third of the travel completed in EV mode.

Regulatory and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled four large carmaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs could pay about €500 extra per year in running expenses than would be estimated under laboratory tests.

“The strong claims that manufacturers often promote about their PHEV cars are clearly way off the truth,” stated a automotive expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are little improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Debate and Industry Pressure

Plug-in hybrid vehicles have lately been brought again into policy discussions as carmakers have pressed the European Union to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced intense pressure from the car sector and resistance from EU countries with significant car manufacturing.

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

An external energy policy specialist, who was unaffiliated with the study, described the report a “highly valuable addition” after a long period in which segments of the automotive industry argued there was too little information to accurately assess real-world emissions.

“The results show, without question, that the difference between official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or diesel cars,” they said. “Any policy changes regarding PHEVs should be made with extreme care and in the light of that evidence.”