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PHEVs release nearly 5x greater planet-heating emissions than official data show, as per a recent report.

Growing Discrepancy Between Lab and Real-World Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than traditional petrol and diesel vehicles, based on analysis carried out by a non-profit organization. That contrasts sharply with laboratory tests, which assumed a 75% decrease in pollution.

Researchers studied information from onboard energy use monitors of 800,000 cars sold in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are falling,” said a lead researcher participating in the report. “This discrepancy is widening and poses a serious problem. As a result, PHEVs pollute nearly as heavily as gasoline cars.”

Key Factors Driving the Emissions Gap

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric mode compared to overall distance. The team found that just 27% of travel was done in EV mode, while lab estimates suggested 84%.

Even, when operating in EV mode, pollution amounts were significantly higher than lab projections. That occurred because EV motors were not strong enough to operate independently, resulting to engines burning fossil fuels for almost one-third of the travel covered in EV mode.

Policy and Economic Consequences

According to calculations, the underestimation of PHEV CO2 output allowed several large automaker groups to avoid over €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 extra per year in running costs than is estimated under lab conditions.

“The strong statements that automakers often promote about their plug-in hybrid cars are obviously far from the mark,” commented a transport expert. “Consumers are being duped into thinking that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and running costs.”

Political Discussion and Industry Pressure

Hybrid vehicles have lately been drawn back into political debates as carmakers have lobbied the European Union to weaken CO₂ standards. A planned prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with large automotive industries.

Some high-level officials have suggested PHEVs as a possible “flexibility” option to introduce in the legislation.

One independent energy economics expert, who was unaffiliated with the study, described the analysis a “very useful contribution” after years in which parts of the automotive industry claimed there was too little information to accurately assess actual CO2 output.

“The results demonstrate, without question, that the gap between official and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” the expert said. “All policy adjustments regarding PHEVs should be implemented with utmost care and in the light of that evidence.”