🔗 Share this article

PHEVs release almost 5x greater planet-heating emissions than official data show, according to a recent analysis.

Widening Gap In Lab and Actual CO2 Output

Data reveals that PHEVs release just one-fifth lower CO₂ than traditional petrol and diesel cars, based on research carried out by a non-profit group. That differs significantly with lab estimates, which assumed a 75% reduction in pollution.

Researchers examined information from onboard energy use meters of 800,000 vehicles sold in the EU from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are decreasing,” stated a lead researcher participating in the report. “That gap is widening and poses a significant problem. As a result, PHEVs emit almost as much as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Researchers linked the majority of the difference to overestimates of the “utility factor” – the percentage of miles travelled in electric mode compared to total mileage. The team found that only 27% of driving was completed in EV mode, while lab assumptions suggested over four-fifths.

Additionally, when running in electric mode, emission amounts were significantly higher than lab estimates. This occurred because electric motors were not strong sufficient to operate alone, leading to combustion motors using gasoline for nearly one-third of the travel covered in electric mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV CO2 output allowed four major carmaker groups to avoid more than €5bn in fines between 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ standards.

Furthermore, drivers of PHEVs could spend about €500 extra per year in running expenses than is assumed under lab conditions.

“The bold claims that automakers like to make about their plug-in hybrid vehicles are obviously way off the mark,” stated a automotive expert. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are little better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been brought again into political discussions as automakers have pressed the EU to weaken CO₂ targets. A planned prohibition on new internal combustion cars in 2035 has faced heavy pressure from the car sector and opposition from EU countries with significant car manufacturing.

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

One independent energy economics expert, who was not involved with the research, described the report a “very useful contribution” after a long period in which parts of the car industry argued there was too little data to properly assess real-world CO2 output.

“These findings show, without question, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel cars,” the expert said. “Any policy adjustments regarding PHEVs should be implemented with extreme caution and considering that data.”