🔗 Share this article

Plug-in hybrid electric vehicles produce nearly 5x greater global warming emissions than official data show, as per a new analysis.

Widening Discrepancy Between Lab and Real-World Emissions

Data shows that PHEVs emit only 19% less CO₂ than traditional gas and diesel vehicles, based on research conducted by a non-profit group. This contrasts significantly with laboratory tests, which assumed a three-quarters reduction in pollution.

Researchers studied information from onboard energy use meters of 800,000 vehicles sold in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” stated a lead researcher participating in the study. “That gap is widening and creates a serious problem. As a result, PHEVs emit almost as much as gasoline vehicles.”

Primary Reasons Driving the Emissions Gap

Analysts attributed most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in battery power relative to overall mileage. They determined that just 27% of driving was completed in electric mode, whereas official estimates assumed 84%.

Additionally, when operating in EV mode, pollution levels were significantly higher than official projections. This happened because EV motors were not strong sufficient to operate alone, resulting to engines burning fossil fuels for almost a third of the distance covered in electric mode.

Policy and Financial Implications

According to calculations, the underestimation of PHEV emissions allowed four large automaker companies to escape over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 more annually in running expenses than is estimated under lab conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are obviously far from the truth,” commented a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are only slightly better than standard gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating costs.”

Policy Discussion and Automotive Pressure

Hybrid vehicles have lately been brought back into policy discussions as carmakers have pressed the EU to relax CO₂ standards. A proposed prohibition on new combustion engine vehicles in 2035 has faced heavy lobbying from the automotive industry and opposition from EU countries with significant car industries.

Some senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to include in the regulation.

One external energy policy expert, who was unaffiliated with the study, described the analysis a “very useful contribution” after a long period in which parts of the car industry argued there was too little data to accurately assess real-world emissions.

“The results demonstrate, without question, that the difference between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional cars,” they said. “Any regulatory changes concerning PHEVs should be made with utmost care and in the light of this data.”