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Plug-in hybrid electric vehicles emit nearly 5x more planet-heating pollution than official data indicate, as per a recent analysis.

Growing Discrepancy Between Official and Real-World CO2 Output

Statistics shows that PHEVs release just one-fifth less CO₂ than traditional petrol and diesel vehicles, according to research carried out by a non-profit group. This contrasts significantly with lab tests, which suggested a 75% reduction in emissions.

Analysts studied data from onboard energy use monitors of 800,000 cars sold in the EU from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a lead researcher involved in the study. “This gap is widening and creates a serious problem. As a result, PHEVs emit almost as much as gasoline cars.”

Key Reasons Driving the Emissions Gap

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric power relative to total mileage. They determined that just 27% of driving was completed in electric mode, while lab assumptions suggested 84%.

Additionally, when operating in electric mode, emission levels were significantly higher than lab estimates. That occurred because EV motors were insufficiently powerful sufficient to operate alone, resulting to engines burning gasoline for nearly one-third of the distance completed in EV mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV CO2 output allowed four major carmaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs could spend about €500 extra per year in operating costs than is assumed under laboratory tests.

“The strong claims that manufacturers like to make about their plug-in hybrid cars are obviously far from the mark,” commented a automotive expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have recently been drawn back into political debates as carmakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced heavy lobbying from the car industry and opposition from EU countries with large automotive manufacturing.

Several senior officials have proposed PHEVs as a possible “compromise” solution to include in the regulation.

One external energy policy expert, who was not involved with the study, described the report a “highly valuable contribution” after a long period in which parts of the automotive industry claimed there was too little data to accurately evaluate real-world emissions.

“These findings show, without question, that the gap in lab and actual PHEV energy use and CO₂ output is much, much larger than for gasoline or conventional vehicles,” they said. “Any regulatory changes regarding PHEVs should be implemented with utmost care and in the light of this evidence.”