🔗 Share this article

Plug-in hybrid electric vehicles emit almost five times greater planet-heating emissions than lab-reported data show, as per a new analysis.

Growing Discrepancy In Lab and Real-World Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel cars, according to analysis carried out by a non-profit organization. This differs significantly with lab tests, which assumed a three-quarters decrease in emissions.

Analysts examined data from onboard fuel consumption monitors of 800,000 vehicles registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” stated a lead analyst participating in the report. “This gap is widening and poses a serious problem. Consequently, PHEVs pollute nearly as much as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery mode compared to total distance. They determined that just a quarter of driving was done in EV mode, whereas lab estimates suggested over four-fifths.

Even, when operating in EV mode, pollution levels were well above official estimates. That occurred because EV motors were not strong sufficient to function alone, resulting to engines burning gasoline for almost a third of the travel covered in electric mode.

Regulatory and Economic Consequences

According to estimates, the lowballing of PHEV CO2 output enabled several large automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend about €500 more annually in operating expenses than is estimated under laboratory tests.

“The bold claims that manufacturers like to make about their plug-in hybrid vehicles are obviously far from the mark,” stated a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy use, CO₂ production, and running expenses.”

Political Debate and Industry Lobbying

Hybrid vehicles have recently been brought again into policy discussions as automakers have lobbied the European Union to relax CO₂ targets. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense pressure from the car industry and opposition from EU countries with large automotive industries.

Some senior officials have suggested plug-in hybrids as a potential “compromise” option to introduce in the legislation.

An external energy policy expert, who was unaffiliated with the research, called the report a “very useful contribution” after a long period in which parts of the car industry claimed there was too little information to properly evaluate real-world emissions.

“These findings show, beyond any doubt, that the difference between lab and actual PHEV energy use and CO₂ output is much, much larger than for petrol or diesel vehicles,” the expert stated. “Any policy changes concerning PHEVs should be made with extreme care and considering this data.”