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PHEVs release almost five times more planet-heating pollution than official figures indicate, as per a recent analysis.

Growing Gap Between Lab and Actual CO2 Output

Data reveals that PHEVs emit only one-fifth less CO₂ than conventional petrol and diesel cars, according to analysis conducted by a non-profit organization. This contrasts sharply with laboratory estimates, which assumed a three-quarters reduction in emissions.

Researchers examined information from in-vehicle fuel consumption meters of 800,000 vehicles sold in the EU between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are decreasing,” stated a lead researcher participating in the report. “This gap is widening and poses a serious problem. As a result, PHEVs pollute almost as heavily as petrol cars.”

Primary Factors Behind the Discrepancy

Researchers linked most of the difference to inflated estimates of the “utility factor” – the percentage of miles driven in electric mode compared to overall mileage. The team found that just a quarter of travel was completed in electric mode, while lab assumptions suggested over four-fifths.

Even, when running in electric mode, emission amounts were significantly higher than lab projections. That occurred because EV motors were insufficiently powerful sufficient to function independently, leading to engines using fossil fuels for almost a third of the distance covered in EV mode.

Policy and Financial Consequences

According to calculations, the lowballing of PHEV emissions enabled four major carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could pay about €500 more annually in running expenses than would be assumed under laboratory tests.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are obviously far from the truth,” commented a transport analyst. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are little improved than regular petrol and diesel cars in terms of energy use, CO₂ production, and running expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been drawn again into policy debates as automakers have lobbied the European Union 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 member states with large car industries.

Several high-level officials have suggested plug-in hybrids as a possible “flexibility” option to include in the legislation.

An independent energy economics specialist, who was unaffiliated with the research, described the analysis a “highly valuable contribution” after a long period in which segments of the car sector claimed there was insufficient information to properly evaluate actual CO2 output.

“The results show, beyond any doubt, that the gap in lab and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional cars,” the expert stated. “Any policy changes regarding PHEVs should be implemented with extreme care and considering this evidence.”