🔗 Share this article

PHEVs emit almost 5x more planet-heating emissions than lab-reported figures show, as per a recent report.

Widening Discrepancy In Official and Real-World CO2 Output

Data reveals that PHEVs release only 19% less CO₂ than conventional gas and diesel cars, according to research carried out by a non-profit organization. That differs significantly with lab tests, which suggested a three-quarters decrease in pollution.

Analysts examined data from in-vehicle fuel consumption monitors of 800,000 cars registered in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” said a lead analyst involved in the report. “This gap is growing and creates a significant issue. Consequently, PHEVs pollute almost as much as gasoline cars.”

Primary Reasons Behind the Discrepancy

Researchers linked most of the gap to overestimates of the “electric driving share” – the ratio of kilometers travelled in battery power compared to total distance. The team determined that just 27% of travel was completed in electric mode, while lab estimates suggested over four-fifths.

Even, when operating in EV mode, emission amounts were well above official projections. This occurred because electric motors were not strong enough to operate independently, leading to engines burning gasoline for almost a third of the travel completed in EV mode.

Regulatory and Financial Consequences

Based on estimates, the underestimation of PHEV CO2 output enabled several major carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs would pay about €500 more per year in running costs than would be assumed under lab conditions.

“The bold claims that manufacturers often promote about their plug-in hybrid vehicles are obviously far from the mark,” stated a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy use, CO₂ production, and operating expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid cars have recently been drawn back into political discussions as automakers have lobbied the European Union to relax CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced intense pressure from the car sector and opposition from member states with significant car industries.

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

One independent energy economics specialist, who was unaffiliated with the study, described the report a “very useful contribution” after a long period in which parts of the automotive industry argued there was insufficient information to accurately assess real-world CO2 output.

“The results demonstrate, without question, that the gap between lab and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or conventional vehicles,” they said. “Any regulatory changes concerning PHEVs should be implemented with utmost caution and in the light of this data.”