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PHEVs produce almost five times greater global warming emissions than lab-reported data indicate, as per a recent analysis.

Growing Discrepancy In Official and Actual CO2 Output

Data reveals that PHEVs release only 19% less CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a non-profit organization. This contrasts significantly with lab tests, which assumed a 75% decrease in emissions.

Researchers studied data from onboard energy use monitors of 800,000 vehicles sold in the EU from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” stated a senior researcher participating in the report. “That discrepancy is widening and poses a serious issue. Consequently, PHEVs emit nearly as much as gasoline cars.”

Primary Factors Behind the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in battery mode relative to total mileage. The team determined that only 27% of travel was completed in electric mode, while lab assumptions assumed 84%.

Additionally, when running in EV mode, pollution levels were well above official projections. That happened because EV motors were not strong enough to function alone, leading to combustion motors using gasoline for almost a third of the travel completed in electric mode.

Policy and Financial Consequences

According to calculations, the underestimation of PHEV CO2 output enabled four major carmaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs could pay about €500 extra annually in operating expenses than would be estimated under laboratory conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are clearly far from the truth,” stated a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of fuel consumption, CO₂ production, and operating costs.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been brought back into policy debates as automakers have lobbied the EU to weaken CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with significant car industries.

Several senior politicians have proposed plug-in hybrids as a potential “flexibility” option to introduce in the regulation.

One external energy economics specialist, who was unaffiliated with the research, described the analysis a “very useful addition” after a long period in which parts of the car industry claimed there was insufficient information to properly assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional cars,” the expert said. “All policy changes regarding PHEVs should be implemented with utmost caution and considering this data.”