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Plug-in hybrid cars produce nearly five times more global warming pollution than official figures indicate, as per a new analysis.

Growing Discrepancy In Lab and Actual Emissions

Data reveals that PHEVs release only one-fifth less CO₂ than traditional gas and diesel vehicles, based on research carried out by a advocacy organization. This differs significantly with lab tests, which suggested a 75% reduction in pollution.

Analysts studied data from in-vehicle energy use monitors of eight hundred thousand vehicles sold in the EU from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” said a senior researcher involved in the study. “That gap is widening and poses a significant issue. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Key Factors Driving the Emissions Gap

Researchers attributed the majority of the gap to inflated estimates of the “electric driving share” – the ratio of miles driven in electric power relative to total distance. They determined that only 27% of travel was done in EV mode, whereas official estimates suggested 84%.

Additionally, when operating in EV mode, pollution amounts were significantly higher than official estimates. That occurred because EV motors were insufficiently powerful sufficient to operate alone, leading to engines using fossil fuels for almost a third of the distance covered in electric mode.

Policy and Economic Consequences

According to estimates, the lowballing of PHEV emissions enabled four large carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ standards.

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

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly way off the mark,” stated a automotive analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and running costs.”

Political Debate and Automotive Pressure

Hybrid cars have recently been drawn back into political debates as automakers have pressed the EU to relax CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive industry and opposition from EU countries with significant car industries.

Several high-level politicians have proposed plug-in hybrids as a possible “flexibility” option to introduce in the regulation.

An external energy policy expert, who was unaffiliated with the study, called the report a “highly valuable addition” after years in which parts of the automotive industry claimed there was insufficient data to accurately assess actual emissions.

“These findings show, beyond any doubt, that the difference in lab and real-world PHEV energy use and CO₂ output is significantly larger than for gasoline or diesel cars,” the expert stated. “Any policy adjustments concerning PHEVs should be implemented with utmost care and in the light of this data.”