🔗 Share this article

Plug-in hybrid electric vehicles emit almost 5x greater planet-heating pollution than official data indicate, as per a new report.

Growing Discrepancy Between Lab and Actual Emissions

Statistics shows that PHEVs emit only 19% less CO₂ than traditional gas and diesel vehicles, according to research carried out by a non-profit group. This contrasts sharply with lab tests, which assumed a three-quarters reduction in emissions.

Researchers examined information from onboard energy use meters of eight hundred thousand cars registered in the EU from 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a lead researcher involved in the report. “That discrepancy is widening and poses a significant problem. Consequently, PHEVs emit nearly as much as gasoline vehicles.”

Key Reasons Driving the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the percentage of miles driven in battery power compared to total mileage. The team found that just 27% of driving was done in electric mode, while official estimates assumed over four-fifths.

Even, when running in EV mode, pollution levels were significantly higher than lab estimates. That happened because electric motors were not strong sufficient to function alone, leading to combustion motors burning gasoline for almost one-third of the distance covered in EV mode.

Policy and Economic Consequences

Based on estimates, the underestimation of PHEV CO2 output enabled several large automaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ standards.

Additionally, owners of PHEVs would spend about €500 more per year in operating costs than is assumed under lab tests.

“The strong statements that manufacturers often promote about their plug-in hybrid vehicles are obviously far from the mark,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little better than regular gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Discussion and Industry Lobbying

Hybrid vehicles have lately been drawn back into political debates as automakers have pressed the European Union to weaken CO₂ standards. A planned ban on sales of new internal combustion cars in 2035 has faced heavy pressure from the car industry and opposition from member states with significant automotive industries.

Several senior officials have suggested plug-in hybrids as a potential “flexibility” option to include in the regulation.

An external energy economics expert, who was unaffiliated with the study, called the analysis a “highly valuable addition” after a long period in which parts of the automotive industry argued there was too little data to accurately evaluate real-world CO2 output.

“These findings show, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” they stated. “Any policy changes concerning PHEVs should be made with extreme care and considering that evidence.”