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Plug-in hybrid electric vehicles emit nearly five times more planet-heating emissions than lab-reported figures indicate, as per a new report.

Growing Discrepancy In Official and Actual Emissions

Data shows that PHEVs emit just one-fifth lower CO₂ than conventional petrol and diesel cars, based on analysis carried out by a non-profit organization. This differs sharply with laboratory estimates, which suggested a 75% decrease in pollution.

Analysts examined information from in-vehicle energy use meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported figures are falling,” stated a lead researcher participating in the study. “That gap is widening and poses a significant problem. As a result, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Driving the Discrepancy

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric power relative to total mileage. They found that only 27% of driving was done in EV mode, while lab estimates assumed 84%.

Even, when running in EV mode, emission levels were significantly higher than lab projections. This happened because electric motors were insufficiently powerful enough to function alone, leading to engines burning gasoline for nearly one-third of the travel covered in electric mode.

Regulatory and Economic Consequences

Based on calculations, the lowballing of PHEV emissions allowed four large carmaker companies to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 more annually in operating costs than is estimated under laboratory tests.

“The strong statements that manufacturers often promote about their plug-in hybrid vehicles are clearly way off the mark,” commented a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of energy use, CO₂ production, and operating costs.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have recently been brought back into policy discussions as automakers have pressed the European Union to relax CO₂ standards. A planned ban on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from EU countries with large automotive manufacturing.

Several senior officials have proposed plug-in hybrids as a possible “compromise” solution to introduce in the regulation.

One external energy policy expert, who was not involved with the research, described the analysis a “highly valuable addition” after a long period in which segments of the car industry claimed there was insufficient information to properly assess real-world emissions.

“The results show, beyond any doubt, that the difference between lab and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” they stated. “All policy changes concerning PHEVs should be made with extreme care and considering that data.”