🔗 Share this article

Plug-in hybrid cars produce nearly 5x more global warming emissions than official data indicate, according to a new report.

Widening Discrepancy In Official and Real-World Emissions

Data shows that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel vehicles, based on research conducted by a advocacy group. That contrasts sharply with laboratory estimates, which suggested a 75% reduction in pollution.

Analysts examined information from onboard energy use meters of eight hundred thousand cars registered in Europe between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” stated a senior analyst participating in the report. “This gap is growing and poses a significant issue. As a result, PHEVs pollute almost as heavily as petrol cars.”

Primary Reasons Driving the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles driven in battery power compared to total mileage. They found that just a quarter of driving was completed in electric mode, while official assumptions suggested 84%.

Even, when operating in electric mode, pollution levels were well above lab estimates. That occurred because EV motors were insufficiently powerful sufficient to operate independently, resulting to combustion motors burning gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed four major carmaker groups to escape over €5bn in penalties from 2021 and 2023, by falsely simplifying adherence with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs would spend about €500 more per year in running costs than is assumed under laboratory conditions.

“The bold claims that automakers often promote about their plug-in hybrid vehicles are clearly far from the truth,” commented a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting money. Actually, PHEVs are little improved than standard gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Debate and Automotive Pressure

Hybrid cars have recently been brought again into political discussions as automakers have pressed the European Union to relax CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and resistance from EU countries with large automotive industries.

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

An external energy economics specialist, who was not involved with the research, described the report a “highly valuable contribution” after a long period in which segments of the automotive industry argued there was too little data to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional vehicles,” they stated. “Any policy adjustments concerning PHEVs should be implemented with utmost caution and in the light of this evidence.”