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Plug-in hybrid electric vehicles release nearly 5x more planet-heating pollution than official figures show, as per a recent analysis.

Growing Discrepancy In Official and Real-World CO2 Output

Statistics reveals that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel cars, according to research carried out by a non-profit organization. That contrasts sharply with lab tests, which assumed a 75% reduction in emissions.

Analysts examined data from in-vehicle energy use meters of 800,000 cars sold in the EU between 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.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” stated a lead researcher participating in the report. “That gap is growing and poses a significant issue. Consequently, PHEVs pollute nearly as heavily as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in battery mode relative to total mileage. The team found that only 27% of driving was completed in EV mode, while lab assumptions assumed over four-fifths.

Additionally, when operating in EV mode, emission amounts were significantly higher than official estimates. That happened because EV motors were not strong enough to operate alone, resulting to combustion motors using gasoline for almost a third of the distance completed in EV mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV CO2 output allowed several major carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 extra per year in running costs than is assumed under laboratory tests.

“The bold statements that automakers like to make about their plug-in hybrid vehicles are clearly way off the truth,” stated a transport expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Discussion and Automotive Lobbying

Hybrid cars have recently been drawn back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and resistance from EU countries with large automotive industries.

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

An independent energy policy specialist, who was not involved with the study, described the analysis a “very useful addition” after a long period in which parts of the automotive industry claimed there was too little information to accurately evaluate actual emissions.

“These findings demonstrate, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional cars,” they said. “All policy adjustments concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”