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Plug-in hybrid cars emit almost five times more global warming emissions than lab-reported figures show, as per a recent report.

Widening Gap Between Lab and Actual Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than conventional gas and diesel vehicles, according to research carried out by a non-profit organization. That contrasts sharply with laboratory tests, which assumed a 75% reduction in emissions.

Analysts examined information from onboard fuel consumption monitors of 800,000 vehicles registered in Europe from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” stated a lead analyst involved in the report. “That gap is growing and creates a serious problem. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Researchers linked most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric mode compared to total distance. They found that only 27% of travel was done in electric mode, whereas official estimates suggested over four-fifths.

Even, when operating in EV mode, pollution levels were significantly higher than lab estimates. This happened because electric motors were not strong sufficient to function alone, leading to combustion motors using gasoline for almost a third of the distance completed in EV mode.

Policy and Financial Implications

According to estimates, the lowballing of PHEV CO2 output allowed four major carmaker groups to avoid more than €5bn in fines between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would spend approximately €500 more annually in operating costs than is assumed under lab conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid vehicles are clearly far from the mark,” stated a automotive expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought again into political debates as carmakers have lobbied the European Union to relax CO₂ targets. A planned prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with significant automotive manufacturing.

Some high-level politicians have suggested plug-in hybrids as a possible “compromise” option to include in the regulation.

An external energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful addition” after years in which segments of the car industry argued there was insufficient data to properly assess real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap between official and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or diesel cars,” the expert said. “All policy adjustments regarding PHEVs should be implemented with utmost care and considering that data.”