🔗 Share this article

Plug-in hybrid cars produce nearly five times greater global warming emissions than lab-reported figures show, as per a new report.

Growing Discrepancy Between Official and Real-World CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than conventional gas and diesel cars, based on research carried out by a non-profit organization. This contrasts sharply with lab tests, which suggested a 75% reduction in pollution.

Analysts studied information from in-vehicle energy use meters of 800,000 cars registered in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” stated a senior analyst participating in the study. “That gap is growing and poses a serious problem. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the ratio of kilometers travelled in battery mode compared to total distance. The team determined that just 27% of travel was done in EV mode, while official estimates suggested over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than lab estimates. That occurred because EV motors were insufficiently powerful enough to function alone, leading to engines using fossil fuels for nearly one-third of the travel covered in electric mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output allowed several large carmaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay about €500 more annually in operating expenses than would be estimated under laboratory tests.

“The bold claims that manufacturers often promote about their PHEV cars are clearly way off the truth,” stated a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy consumption, CO₂ production, and running expenses.”

Policy Debate and Industry Pressure

Plug-in hybrid cars have recently been brought again into policy debates as carmakers have pressed the European Union to relax CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large automotive manufacturing.

Several high-level politicians have proposed plug-in hybrids as a possible “flexibility” solution to introduce in the legislation.

One external energy economics specialist, who was not involved with the research, called the analysis a “highly valuable contribution” after a long period in which segments of the car industry claimed there was too little information to accurately evaluate real-world CO2 output.

“These findings demonstrate, without question, that the gap between official and actual PHEV energy use and CO₂ emissions is significantly larger than for petrol or diesel vehicles,” the expert said. “Any regulatory adjustments regarding PHEVs should be implemented with extreme caution and in the light of that data.”