Plug-in Hybrid Vehicles Pollute Almost as Heavily as Gasoline Vehicles, Study Reveals

Plug-in hybrid cars emit almost five times greater planet-heating emissions than lab-reported data show, as per a recent analysis.

Widening Gap In Lab and Actual CO2 Output

Statistics shows that PHEVs release just 19% lower CO₂ than traditional gas and diesel cars, based on research conducted by a non-profit group. This contrasts significantly with laboratory tests, which suggested a 75% decrease in pollution.

Analysts studied data from in-vehicle energy use meters of 800,000 cars sold in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, up from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported figures are falling,” said a senior researcher involved in the report. “That discrepancy is widening and poses a significant issue. Consequently, PHEVs pollute almost as much as gasoline cars.”

Key Factors Behind the Emissions Gap

Analysts linked most of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to overall distance. The team determined that just 27% of driving was done in EV mode, whereas lab assumptions suggested 84%.

Additionally, when operating in electric mode, pollution levels were well above official projections. This happened because EV motors were not strong sufficient to function alone, leading to combustion motors burning gasoline for almost one-third of the distance completed in EV mode.

Policy and Financial Consequences

According to calculations, the underestimation of PHEV CO2 output enabled several large automaker companies to escape more than €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 extra annually in running costs than would be estimated under laboratory conditions.

“The bold claims that automakers often promote about their PHEV cars are clearly way off the mark,” stated a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the environment and saving costs. Actually, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy use, CO₂ emissions, and running costs.”

Political Discussion and Automotive Pressure

Plug-in hybrid vehicles have recently been drawn again into policy debates as automakers have pressed the EU to weaken CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the car industry and opposition from EU countries with large automotive industries.

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

One independent energy policy specialist, who was not involved with the research, described the report a “highly valuable addition” after a long period in which segments of the car sector claimed there was too little data to accurately assess actual emissions.

“The results demonstrate, without question, that the difference in lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel vehicles,” they stated. “All regulatory adjustments regarding PHEVs should be implemented with extreme caution and in the light of this evidence.”