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Plug-in hybrid cars emit almost five times greater planet-heating emissions than lab-reported data show, as per a recent analysis.

Widening Discrepancy In Official and Actual Emissions

Data shows that PHEVs emit only one-fifth less CO₂ than conventional petrol and diesel cars, according to analysis carried out by a advocacy group. This differs sharply with lab tests, which suggested a 75% decrease in pollution.

Analysts examined data from onboard fuel consumption meters of eight hundred thousand cars registered in the EU between 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior analyst involved in the study. “That gap is growing and creates a significant problem. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in battery power compared to total distance. They found that only 27% of travel was done in electric mode, while official estimates assumed over four-fifths.

Even, when operating in EV mode, emission levels were well above official projections. That occurred because electric motors were insufficiently powerful enough to function independently, resulting to engines burning gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled four large automaker groups to escape more than €5bn in fines between 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would spend about €500 extra per year in running costs than is assumed under laboratory conditions.

“The bold claims that automakers often promote about their plug-in hybrid cars are clearly way off the mark,” commented a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Policy Debate and Industry Lobbying

Plug-in hybrid vehicles have lately been drawn again into policy discussions as carmakers have pressed the European Union to relax CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with large car industries.

Some senior officials have suggested PHEVs as a possible “flexibility” solution to introduce in the legislation.

An independent energy economics expert, who was unaffiliated with the research, called the analysis a “highly valuable addition” after a long period in which parts of the car sector argued there was too little information to properly evaluate real-world emissions.

“These findings demonstrate, without question, that the difference between lab and real-world PHEV energy use and CO₂ output is much, much larger than for petrol or conventional cars,” they said. “Any regulatory adjustments concerning PHEVs should be made with extreme caution and considering this evidence.”