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Plug-in hybrid cars release nearly 5x more planet-heating emissions than official data show, as per a recent analysis.

Growing Discrepancy Between Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit only 19% lower CO₂ than conventional gas and diesel cars, based on analysis carried out by a advocacy group. That contrasts significantly with lab tests, which assumed a 75% decrease in pollution.

Researchers studied data from onboard fuel consumption monitors of eight hundred thousand cars registered in Europe from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are falling,” stated a senior analyst participating in the report. “That discrepancy is widening and creates a serious problem. Consequently, PHEVs pollute nearly as much as petrol vehicles.”

Key Reasons Behind the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric mode relative to overall mileage. The team found that just 27% of travel was done in electric mode, while official assumptions suggested 84%.

Additionally, when operating in EV mode, pollution levels were significantly higher than lab estimates. This happened because electric motors were not strong sufficient to operate independently, leading to combustion motors using fossil fuels for almost one-third of the distance covered in electric mode.

Policy and Financial Implications

Based on estimates, the lowballing of PHEV emissions allowed several large carmaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 more per year in operating expenses than is assumed under laboratory tests.

“The bold claims that manufacturers often promote about their PHEV cars are clearly far from the mark,” commented a automotive analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy consumption, CO₂ production, and running expenses.”

Policy Discussion and Industry Lobbying

Hybrid vehicles have lately been drawn again into policy discussions as carmakers have lobbied the EU to relax CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy pressure from the automotive industry and resistance from EU countries with large car manufacturing.

Several senior officials have proposed plug-in hybrids as a possible “flexibility” option to introduce in the legislation.

One external energy policy specialist, who was unaffiliated with the research, called the analysis a “very useful addition” after a long period in which segments of the car sector argued there was insufficient information to accurately assess actual emissions.

“The results show, beyond any doubt, that the gap between official and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel cars,” the expert stated. “Any regulatory changes concerning PHEVs should be implemented with extreme care and considering that data.”