🔗 Share this article

PHEVs emit almost five times greater planet-heating pollution than official data show, as per a recent analysis.

Widening Discrepancy In Lab and Real-World CO2 Output

Statistics shows that PHEVs release only 19% less CO₂ than conventional gas and diesel cars, according to research carried out by a non-profit organization. That differs sharply with lab tests, which assumed a 75% reduction in pollution.

Analysts examined information from in-vehicle energy use meters of 800,000 vehicles sold in the EU from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” stated a lead analyst participating in the study. “This discrepancy is growing and poses a serious problem. As a result, PHEVs emit almost as much as petrol vehicles.”

Primary Reasons Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “utility factor” – the percentage of kilometers driven in battery power compared to total mileage. The team determined that only 27% of driving was done in EV mode, whereas official assumptions suggested 84%.

Even, when operating in electric mode, pollution levels were significantly higher than official estimates. This happened because electric motors were not strong sufficient to operate alone, leading to engines burning fossil fuels for nearly one-third of the travel covered in EV mode.

Regulatory and Economic Implications

Based on estimates, the underestimation of PHEV CO2 output enabled several large carmaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 extra per year in running expenses than would be assumed under laboratory conditions.

“The bold statements that manufacturers like to make about their plug-in hybrid cars are clearly far from the truth,” stated a transport analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly better than standard gas and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Political Debate and Automotive Pressure

Hybrid vehicles have lately been drawn back into policy discussions as carmakers have lobbied the European Union to relax CO₂ standards. A planned ban on sales of new internal combustion cars in 2035 has faced intense pressure from the car sector and resistance from EU countries with large automotive industries.

Several high-level politicians have proposed plug-in hybrids as a possible “compromise” option to include in the legislation.

One external energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which segments of the car sector claimed there was insufficient information to properly evaluate real-world CO2 output.

“The results show, without question, that the gap between official and actual PHEV fuel consumption and CO₂ emissions is significantly larger than for petrol or conventional vehicles,” the expert stated. “All policy changes regarding PHEVs should be implemented with extreme care and in the light of that data.”