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PHEVs produce almost 5x more global warming pollution than lab-reported data indicate, according to a recent report.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release only 19% lower CO₂ than conventional petrol and diesel cars, based on analysis carried out by a advocacy organization. That contrasts significantly with laboratory estimates, which assumed a 75% decrease in pollution.

Analysts examined data from in-vehicle fuel consumption monitors of eight hundred thousand cars sold in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from three and a half times in 2021.

“Actual emissions are increasing, while official figures are falling,” said a lead analyst involved in the study. “This gap is widening and creates a significant problem. Consequently, PHEVs pollute almost as heavily as petrol cars.”

Key Factors Driving the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers driven in electric mode compared to total mileage. They found that only 27% of driving was completed in EV mode, whereas official assumptions suggested 84%.

Even, when running in electric mode, pollution levels were significantly higher than official projections. That occurred because EV motors were insufficiently powerful enough to function alone, resulting to combustion motors using gasoline for nearly one-third of the travel covered in EV mode.

Policy and Financial Implications

According to calculations, the underestimation of PHEV emissions allowed several major automaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ standards.

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

“The bold statements that manufacturers like to make about their plug-in hybrid cars are obviously way off the truth,” stated a transport analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are little improved than regular petrol and diesel vehicles in terms of energy use, CO₂ emissions, and running costs.”

Political Debate and Industry Lobbying

Hybrid vehicles have lately been brought again into policy debates as automakers have pressed the European Union to relax CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with large car manufacturing.

Some high-level politicians have proposed PHEVs as a potential “flexibility” solution to introduce in the regulation.

An independent energy policy specialist, who was not involved with the research, called the report a “very useful addition” after a long period in which parts of the car industry argued there was insufficient data to properly evaluate actual CO2 output.

“The results show, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ output is much, much greater than for petrol or conventional cars,” they stated. “Any policy changes regarding PHEVs should be implemented with extreme care and in the light of that data.”