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Plug-in hybrid cars produce almost 5x more planet-heating pollution than official data show, as per a recent analysis.

Growing Discrepancy In Lab and Actual CO2 Output

Data reveals that PHEVs emit only 19% lower CO₂ than conventional petrol and diesel cars, based on analysis carried out by a non-profit group. This contrasts significantly with laboratory tests, which suggested a 75% decrease in emissions.

Researchers examined data from onboard fuel consumption meters of 800,000 cars sold in Europe between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while official emissions are decreasing,” stated a lead analyst participating in the report. “This discrepancy is widening and poses a serious problem. Consequently, PHEVs emit almost as heavily as petrol cars.”

Key Reasons Driving the Discrepancy

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the percentage of kilometers travelled in battery mode relative to overall distance. The team found that only 27% of travel was completed in electric mode, while lab estimates suggested 84%.

Additionally, when running in EV mode, emission amounts were well above lab projections. This occurred because electric motors were not strong enough to function independently, leading to combustion motors using gasoline for nearly one-third of the travel completed in EV mode.

Regulatory and Economic Implications

Based on estimates, the lowballing of PHEV CO2 output enabled four major carmaker companies to escape more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay approximately €500 more per year in operating costs than is estimated under lab tests.

“The bold claims that automakers like to make about their PHEV cars are clearly far from the mark,” stated a automotive analyst. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and running costs.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been brought again into policy discussions as carmakers have lobbied the European Union to relax CO₂ targets. A planned ban on new combustion engine cars in 2035 has faced intense pressure from the automotive sector and opposition from member states with significant automotive industries.

Several senior officials have suggested PHEVs as a potential “flexibility” solution to include in the regulation.

An external energy policy expert, who was not involved with the research, described the analysis a “highly valuable addition” after years in which segments of the automotive sector argued there was insufficient data to properly evaluate actual emissions.

“These findings demonstrate, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ output is much, much larger than for petrol or diesel vehicles,” the expert said. “Any regulatory adjustments concerning PHEVs should be made with utmost care and considering this evidence.”