🔗 Share this article

PHEVs release almost five times greater planet-heating emissions than official figures indicate, according to a new analysis.

Widening Discrepancy Between Official and Real-World Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than conventional gas and diesel cars, based on research carried out by a advocacy group. This differs significantly with lab estimates, which assumed a 75% reduction in emissions.

Analysts studied data from in-vehicle energy use meters of eight hundred thousand cars registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab figures, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are decreasing,” stated a senior analyst involved in the report. “This gap is growing and poses a serious problem. Consequently, PHEVs emit almost as heavily as petrol vehicles.”

Key Reasons Behind the Emissions Gap

Researchers linked the majority of the difference to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery power relative to overall mileage. The team determined that only a quarter of driving was done in EV mode, whereas official assumptions assumed over four-fifths.

Even, when running in EV mode, emission levels were well above lab projections. That occurred because electric motors were not strong sufficient to operate independently, leading to engines using fossil fuels for almost a third of the distance covered in electric mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV emissions allowed several large carmaker groups to escape over €5bn in fines between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay about €500 extra per year in operating expenses than is estimated under laboratory conditions.

“The bold statements that manufacturers often promote about their PHEV cars are obviously far from the mark,” commented a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy use, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Pressure

Plug-in hybrid cars have recently been drawn back into policy discussions as automakers have lobbied the EU to weaken CO₂ standards. A planned ban on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and opposition from EU countries with large car industries.

Some senior politicians have suggested plug-in hybrids as a potential “flexibility” option to introduce in the regulation.

An independent energy policy expert, who was unaffiliated with the study, called the analysis a “highly valuable contribution” after a long period in which segments of the car industry claimed there was insufficient information to accurately assess real-world CO2 output.

“These findings show, without question, that the difference between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” the expert said. “All regulatory adjustments concerning PHEVs should be made with utmost caution and in the light of this data.”