Plug-in Hybrid electric Vehicles Pollute Nearly as Heavily as Gasoline Cars, Study Finds

Plug-in hybrid cars emit nearly five times more planet-heating emissions than official data show, as per a recent report.

Growing Gap Between Lab and Actual CO2 Output

Data shows that PHEVs emit only one-fifth lower CO₂ than conventional gas and diesel vehicles, according to research carried out by a non-profit organization. This contrasts significantly with lab estimates, which assumed a three-quarters reduction in emissions.

Analysts examined data from onboard energy use monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” stated a senior analyst participating in the study. “This discrepancy is widening and poses a serious problem. Consequently, PHEVs pollute almost as much as petrol cars.”

Key Factors Driving the Discrepancy

Researchers attributed most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric power compared to overall distance. The team found that just a quarter of driving was done in electric mode, while lab estimates suggested 84%.

Even, when running in EV mode, pollution levels were significantly higher than lab projections. This occurred because electric motors were insufficiently powerful enough to function independently, leading to combustion motors burning fossil fuels for nearly one-third of the distance completed in EV mode.

Regulatory and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled several large automaker groups to escape over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would spend about €500 extra annually in operating expenses than is assumed under laboratory tests.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are clearly far from the truth,” stated a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and saving costs. Actually, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating costs.”

Political Debate and Industry Lobbying

Plug-in hybrid vehicles have recently been brought back into policy debates as automakers have lobbied the EU to relax CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced intense lobbying from the car industry and resistance from EU countries with large automotive manufacturing.

Some senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to include in the legislation.

One independent energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful addition” after years in which parts of the automotive industry argued there was insufficient data to accurately assess real-world CO2 output.

“These findings demonstrate, without question, that the difference in lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or conventional cars,” the expert stated. “Any regulatory adjustments regarding PHEVs should be made with extreme caution and in the light of that evidence.”