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Plug-in hybrid cars emit nearly five times greater planet-heating emissions than official data indicate, as per a new analysis.

Growing Gap In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release only 19% less CO₂ than traditional petrol and diesel cars, based on analysis carried out by a advocacy group. That contrasts sharply with lab tests, which assumed a 75% reduction in emissions.

Analysts examined information from in-vehicle energy use meters of 800,000 vehicles sold in the EU from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are decreasing,” stated a lead researcher involved in the report. “This gap is widening and creates a significant problem. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Primary Factors Behind the Emissions Gap

Researchers linked most of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in electric mode relative to total mileage. The team determined that only 27% of driving was done in EV mode, whereas official assumptions assumed over four-fifths.

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

Regulatory and Financial Implications

According to calculations, the underestimation of PHEV CO2 output enabled four large carmaker groups to escape over €5bn in fines between 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay about €500 more annually in running costs than is estimated under lab conditions.

“The bold statements that automakers like to make about their plug-in hybrid vehicles are obviously way off the mark,” stated a transport analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly better than standard gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid cars have lately been drawn back into policy discussions as carmakers have pressed the European Union to relax CO₂ standards. A proposed ban on new internal combustion cars in 2035 has faced heavy lobbying from the automotive industry and resistance from member states with significant car manufacturing.

Several senior politicians have proposed PHEVs as a possible “flexibility” option to include in the regulation.

One external energy policy specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which segments of the automotive sector argued there was too little data to accurately assess real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional cars,” the expert stated. “All regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering this data.”