Plug-in Hybrid electric Cars Emit Almost as Much as Petrol Cars, Study Reveals

Plug-in hybrid electric vehicles release almost 5x greater planet-heating pollution than official data show, as per a recent analysis.

Growing Gap In Lab and Actual CO2 Output

Statistics shows that PHEVs emit only 19% less CO₂ than conventional gas and diesel vehicles, based on research carried out by a non-profit organization. That contrasts significantly with lab tests, which assumed a 75% decrease in pollution.

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

“Actual emissions are increasing, while official figures are decreasing,” said a lead analyst participating in the study. “This discrepancy is widening and poses a serious issue. As a result, PHEVs emit nearly as heavily as petrol cars.”

Key Reasons Driving the Discrepancy

Analysts linked most of the gap to inflated estimates of the “electric driving share” – the ratio of kilometers driven in electric power relative to overall mileage. They found that only a quarter of travel was completed in electric mode, while official assumptions suggested over four-fifths.

Even, when operating in electric mode, pollution levels were well above lab projections. This happened because electric motors were not strong enough to function alone, resulting to engines using gasoline for nearly a third of the distance covered in electric mode.

Policy and Financial Consequences

According to estimates, the underestimation of PHEV emissions allowed several large carmaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 extra annually in running costs than would be estimated under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid cars are clearly way off the truth,” stated a transport expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Pressure

Plug-in hybrid cars have lately been brought back into political debates as carmakers have lobbied the EU to weaken CO₂ standards. A proposed prohibition on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and opposition from EU countries with large automotive manufacturing.

Several high-level officials have suggested PHEVs as a possible “compromise” option to include in the legislation.

An independent energy policy specialist, who was unaffiliated with the study, described the report a “very useful contribution” after years in which parts of the automotive sector claimed there was insufficient data to accurately evaluate real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in lab and actual PHEV energy use and CO₂ output is significantly greater than for petrol or diesel vehicles,” the expert stated. “All regulatory adjustments regarding PHEVs should be implemented with extreme care and considering this evidence.”