🔗 Share this article

Plug-in hybrid electric vehicles emit almost 5x more planet-heating emissions than lab-reported data indicate, according to a new report.

Widening Discrepancy Between Official and Actual CO2 Output

Statistics shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a advocacy organization. This contrasts sharply with lab tests, which suggested a 75% decrease in emissions.

Analysts studied information from in-vehicle energy use monitors of 800,000 vehicles sold in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are falling,” stated a senior researcher involved in the study. “That discrepancy is widening and creates a significant problem. As a result, PHEVs emit almost as heavily as petrol cars.”

Key Factors Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric power relative to overall mileage. The team found that just a quarter of travel was completed in electric mode, while official estimates suggested 84%.

Additionally, when operating in electric mode, pollution amounts were significantly higher than official estimates. This occurred because EV motors were insufficiently powerful enough to function independently, resulting to engines burning gasoline for nearly a third of the travel completed in EV mode.

Policy and Financial Consequences

According to estimates, the lowballing of PHEV emissions enabled four major carmaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs would spend approximately €500 extra annually in running costs than would be assumed under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid cars are clearly far from the mark,” commented a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating expenses.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have lately been drawn again into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced heavy pressure from the car sector and resistance from EU countries with large automotive manufacturing.

Some senior politicians have proposed plug-in hybrids as a possible “compromise” solution to include in the legislation.

One independent energy economics expert, who was unaffiliated with the study, described the report a “highly valuable contribution” after years in which segments of the car sector claimed there was too little information to properly assess real-world emissions.

“The results show, without question, that the gap between lab and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional vehicles,” the expert said. “Any policy changes regarding PHEVs should be implemented with extreme care and considering that evidence.”