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PHEVs produce nearly 5x more global warming pollution than official data show, as per a recent report.

Growing Discrepancy In Official and Real-World CO2 Output

Statistics shows that PHEVs emit just one-fifth less CO₂ than conventional gas and diesel cars, according to analysis carried out by a non-profit organization. That differs significantly with lab tests, which suggested a three-quarters reduction in emissions.

Analysts examined data from in-vehicle fuel consumption monitors of eight hundred thousand cars sold 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 emissions are rising, while lab-reported figures are falling,” stated a lead researcher involved in the study. “This gap is widening and poses a serious problem. As a result, PHEVs emit almost as much as petrol cars.”

Key Reasons Behind the Discrepancy

Analysts linked most of the difference to overestimates of the “utility factor” – the ratio of kilometers driven in electric mode compared to overall distance. The team determined that just 27% of travel was done in EV mode, whereas lab assumptions assumed over four-fifths.

Additionally, when running in EV mode, emission amounts were well above official projections. That happened because electric motors were not strong enough to function independently, leading to combustion motors using fossil fuels for nearly one-third of the distance completed in electric mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled four large carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs would pay about €500 extra annually in running expenses than is assumed under laboratory tests.

“The strong claims that automakers often promote about their plug-in hybrid vehicles are clearly far from the mark,” stated a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are little better than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Policy Debate and Automotive Pressure

Hybrid vehicles have lately been drawn back into policy discussions as carmakers have pressed the EU to weaken CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced heavy lobbying from the automotive industry and resistance from EU countries with significant automotive manufacturing.

Several high-level politicians have proposed plug-in hybrids as a potential “flexibility” option to include in the regulation.

One external energy economics expert, who was unaffiliated with the research, called the report a “very useful contribution” after years in which parts of the automotive sector argued there was too little information to properly assess actual CO2 output.

“These findings demonstrate, without question, that the difference in official and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they said. “Any policy adjustments regarding PHEVs should be implemented with utmost caution and in the light of this evidence.”