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PHEVs emit nearly 5x more planet-heating pollution than official figures show, according to a recent analysis.

Growing Discrepancy Between Official and Actual CO2 Output

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

Analysts studied data from onboard energy use monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are falling,” stated a senior researcher participating in the report. “This gap is widening and creates a significant issue. Consequently, PHEVs emit almost as much as gasoline cars.”

Primary Factors Behind the Emissions Gap

Researchers linked the majority of the gap to inflated estimates of the “electric driving share” – the ratio of kilometers travelled in electric power compared to total mileage. The team found that just 27% of travel was done in electric mode, whereas lab assumptions assumed over four-fifths.

Additionally, when running in electric mode, emission levels were significantly higher than official projections. That occurred because EV motors were not strong sufficient to function independently, resulting to combustion motors using gasoline for nearly a third of the travel covered in electric mode.

Regulatory and Financial Consequences

According to estimates, the lowballing of PHEV emissions enabled four large automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would spend approximately €500 extra per year in running expenses than is assumed under laboratory tests.

“The strong claims that automakers like to make about their PHEV cars are clearly far from the mark,” stated a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the environment and cutting money. Actually, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Policy Discussion and Automotive Lobbying

Hybrid vehicles have lately been drawn back into policy debates as automakers have lobbied the European Union to weaken CO₂ targets. A proposed ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the automotive industry and opposition from member states with large car manufacturing.

Some high-level officials have suggested plug-in hybrids as a potential “compromise” option to include in the regulation.

An external energy policy expert, who was unaffiliated with the research, described the analysis a “very useful addition” after a long period in which segments of the car industry argued there was too little information to properly assess real-world emissions.

“The results show, without question, that the difference in lab and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or conventional cars,” they said. “All regulatory changes concerning PHEVs should be made with extreme care and in the light of this evidence.”