🔗 Share this article

Plug-in hybrid cars emit nearly 5x more planet-heating pollution than official figures show, according to a new analysis.

Widening Discrepancy In Official and Actual Emissions

Statistics reveals that PHEVs release only one-fifth less CO₂ than conventional gas and diesel vehicles, based on analysis carried out by a non-profit organization. That contrasts sharply with laboratory tests, which assumed a 75% reduction in pollution.

Analysts examined data from onboard fuel consumption monitors of 800,000 cars registered in the EU between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are decreasing,” said a lead researcher participating in the report. “This gap is widening and creates a significant issue. As a result, PHEVs pollute almost as much as gasoline cars.”

Primary Factors Behind the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in battery mode compared to total mileage. The team found that only 27% of travel was completed in EV mode, while lab assumptions suggested 84%.

Additionally, when operating in EV mode, emission levels were well above official estimates. This occurred because electric motors were insufficiently powerful sufficient to operate alone, leading to engines burning gasoline for nearly a third of the distance completed in EV mode.

Policy and Economic Consequences

Based on estimates, the lowballing of PHEV emissions allowed several large automaker companies to avoid over €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend about €500 extra annually in running costs than would be estimated under lab tests.

“The bold claims that automakers often promote about their plug-in hybrid cars are obviously far from the mark,” stated a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are little better than standard gas and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been drawn back into political debates as carmakers have lobbied the EU to relax CO₂ targets. A planned ban on sales of new internal combustion cars in 2035 has faced intense lobbying from the car sector and opposition from EU countries with significant automotive industries.

Several high-level officials have suggested PHEVs as a potential “flexibility” option to include in the regulation.

One external energy policy expert, who was unaffiliated with the research, described the analysis a “highly valuable contribution” after years in which segments of the car industry claimed there was too little data to accurately assess real-world emissions.

“These findings show, without question, that the difference between lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” the expert said. “Any policy changes regarding PHEVs should be implemented with extreme caution and considering this evidence.”