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Plug-in hybrid cars emit nearly five times greater planet-heating pollution than lab-reported figures indicate, as per a recent report.

Growing Discrepancy In Lab and Actual Emissions

Statistics shows that PHEVs release just 19% lower CO₂ than conventional petrol and diesel cars, according to analysis carried out by a advocacy organization. This differs significantly with laboratory tests, which suggested a three-quarters reduction in emissions.

Analysts studied information from in-vehicle energy use meters of eight hundred thousand vehicles sold in the EU from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” said a lead researcher participating in the report. “This discrepancy is widening and creates a serious issue. Consequently, PHEVs emit nearly as heavily as petrol cars.”

Primary Reasons Behind the Emissions Gap

Analysts attributed most of the difference to overestimates of the “utility factor” – the percentage of miles driven in electric mode relative to overall distance. The team determined that only a quarter of driving was done in EV mode, while lab estimates suggested 84%.

Even, when running in electric mode, emission amounts were significantly higher than official estimates. That occurred because electric motors were not strong enough to operate alone, resulting to engines using fossil fuels for nearly a third of the travel completed in EV mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV emissions enabled four large carmaker groups to avoid over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs could pay about €500 extra per year in running expenses than is assumed under laboratory tests.

“The strong statements that automakers like to make about their PHEV cars are obviously way off the mark,” commented a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly better than regular petrol and diesel cars in terms of fuel consumption, CO₂ production, and running expenses.”

Policy Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought again into political debates as carmakers have pressed the European Union to weaken CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large car industries.

Several senior politicians have proposed plug-in hybrids as a potential “compromise” solution to include in the regulation.

An independent energy policy specialist, who was not involved with the study, called the analysis a “very useful addition” after a long period in which segments of the automotive industry claimed there was too little information to accurately assess real-world CO2 output.

“The results show, without question, that the difference in lab and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or conventional cars,” the expert said. “Any policy changes concerning PHEVs should be implemented with utmost caution and in the light of that data.”