🔗 Share this article

Plug-in hybrid electric vehicles release almost 5x more planet-heating emissions than lab-reported data show, according to a recent report.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics shows that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel vehicles, according to research carried out by a non-profit organization. That differs significantly with lab estimates, which suggested a 75% reduction in pollution.

Researchers examined information from onboard fuel consumption meters of 800,000 cars registered in Europe between 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official figures, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” stated a senior analyst participating in the report. “That gap is widening and creates a serious problem. As a result, PHEVs pollute almost as heavily as gasoline cars.”

Key Factors Behind the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in electric power relative to overall mileage. The team determined that only 27% of driving was completed in electric mode, while official assumptions assumed 84%.

Even, when running in electric mode, pollution amounts were significantly higher than official estimates. That happened because EV motors were not strong enough to function alone, leading to engines burning fossil fuels for nearly a third of the travel covered in EV mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions allowed several large carmaker groups to avoid more than €5bn in fines from 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 more annually in operating costs than would be assumed under lab conditions.

“The bold claims that automakers like to make about their PHEV vehicles are clearly far from the mark,” stated a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running costs.”

Policy Debate and Automotive Pressure

Plug-in hybrid vehicles have recently been drawn back into policy debates as automakers have pressed the European Union to relax CO₂ standards. A planned ban on new internal combustion cars in 2035 has faced intense pressure from the car sector and resistance from EU countries with significant automotive manufacturing.

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

An independent energy policy specialist, who was unaffiliated with the research, called the analysis a “very useful addition” after years in which segments of the car sector argued there was insufficient information to accurately evaluate real-world emissions.

“These findings show, without question, that the difference in official and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or conventional cars,” they said. “All regulatory adjustments concerning PHEVs should be implemented with extreme caution and considering this data.”