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PHEVs produce nearly 5x greater planet-heating pollution than official figures show, according to a recent analysis.

Growing Gap In Official and Real-World CO2 Output

Data shows that PHEVs emit only one-fifth less CO₂ than conventional petrol and diesel cars, based on analysis conducted by a advocacy organization. That differs sharply with lab tests, which assumed a three-quarters decrease in pollution.

Researchers examined data from onboard fuel consumption meters of eight hundred thousand vehicles sold in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” stated a lead analyst involved in the report. “That discrepancy is widening and poses a serious problem. Consequently, PHEVs pollute almost as heavily as gasoline vehicles.”

Key Reasons Behind the Discrepancy

Researchers linked most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in battery mode relative to total mileage. They found that just a quarter of driving was completed in EV mode, whereas official estimates suggested 84%.

Additionally, when operating in EV mode, emission amounts were significantly higher than lab estimates. This happened because EV motors were not strong sufficient to operate alone, resulting to engines using fossil fuels for almost a third of the distance covered in electric mode.

Regulatory and Financial Implications

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

Furthermore, drivers of PHEVs would spend about €500 extra per year in operating expenses than is assumed under laboratory tests.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are obviously 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 little improved than regular gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running costs.”

Political Debate and Automotive Lobbying

Hybrid cars have recently been brought back into policy debates as automakers have pressed the European Union to weaken CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive sector and opposition from member states with significant car manufacturing.

Some high-level officials have suggested plug-in hybrids as a potential “flexibility” solution to introduce in the legislation.

One external energy economics expert, who was not involved with the study, described the analysis a “very useful contribution” after years in which parts of the automotive sector argued there was insufficient data to properly assess actual emissions.

“The results show, without question, that the difference between lab and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” they stated. “Any policy adjustments regarding PHEVs should be made with extreme care and considering that data.”