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PHEVs emit almost five times more global warming emissions than lab-reported figures indicate, as per a recent report.

Widening Discrepancy In Official and Actual CO2 Output

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than traditional gas and diesel cars, according to analysis carried out by a non-profit organization. That differs significantly with lab estimates, which suggested a three-quarters reduction in emissions.

Researchers examined information from onboard energy use monitors of 800,000 cars sold in the EU from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” said a senior analyst participating in the report. “This discrepancy is growing and creates a serious problem. As a result, PHEVs emit almost as heavily as gasoline cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the difference to overestimates of the “utility factor” – the ratio of miles driven in electric power relative to overall mileage. They found that only a quarter of driving was done in EV mode, whereas official assumptions assumed 84%.

Even, when running in EV mode, pollution levels were well above lab estimates. That occurred because electric motors were not strong sufficient to function alone, resulting to combustion motors using fossil fuels for almost a third of the travel covered in EV mode.

Policy and Economic Implications

Based on estimates, the lowballing of PHEV emissions allowed four major carmaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

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

“The bold claims that manufacturers often promote about their plug-in hybrid vehicles are clearly way off the truth,” commented a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running costs.”

Policy Discussion and Industry Lobbying

Hybrid cars have lately been brought back into political debates as carmakers have lobbied the EU to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the car industry and opposition from member states with large automotive manufacturing.

Some high-level officials have suggested plug-in hybrids as a possible “flexibility” option to include in the legislation.

An external energy policy specialist, who was unaffiliated with the research, described the report a “highly valuable contribution” after a long period in which segments of the car sector claimed there was too little data to properly evaluate real-world CO2 output.

“The results show, without question, that the difference between lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or diesel cars,” they stated. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of this data.”