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PHEVs produce almost five times greater planet-heating emissions than lab-reported figures indicate, as per a recent report.

Widening Discrepancy In Lab and Actual Emissions

Data reveals that PHEVs release just 19% lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a non-profit group. This contrasts sharply with laboratory tests, which suggested a three-quarters reduction in pollution.

Analysts studied information from onboard fuel consumption monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported figures are decreasing,” stated a lead researcher involved in the study. “That discrepancy is widening and creates a significant problem. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Primary Reasons Behind the Emissions Gap

Researchers attributed the majority of the difference to overestimates of the “utility factor” – the percentage of kilometers driven in electric mode compared to total mileage. They determined that only a quarter of driving was done in EV mode, while lab estimates assumed 84%.

Additionally, when operating in electric mode, pollution levels were significantly higher than lab estimates. That occurred because electric motors were not strong sufficient to operate alone, leading to engines burning fossil fuels for almost a third of the travel covered in electric mode.

Policy and Financial Consequences

According to estimates, the lowballing of PHEV emissions enabled four large automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 more per year in running expenses than is estimated under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid cars are clearly way off the mark,” stated a automotive expert. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are little better than regular gas and diesel cars in terms of energy consumption, CO₂ emissions, and operating costs.”

Policy Debate and Automotive Lobbying

Plug-in hybrid vehicles have recently been brought again into political discussions as automakers have pressed the European Union to relax CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and resistance from member states with significant car manufacturing.

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

One external energy economics specialist, who was not involved with the study, described the report a “very useful contribution” after years in which segments of the automotive industry claimed there was too little information to accurately evaluate actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel cars,” they stated. “Any policy changes regarding PHEVs should be made with utmost caution and considering that evidence.”