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Plug-in hybrid electric vehicles produce almost five times more planet-heating emissions than official figures indicate, as per a recent analysis.

Widening Gap In Lab and Real-World CO2 Output

Statistics reveals that PHEVs emit just one-fifth less CO₂ than conventional gas and diesel cars, according to analysis carried out by a advocacy organization. That differs sharply with lab tests, which suggested a three-quarters decrease in pollution.

Analysts examined information from onboard energy use monitors of 800,000 vehicles sold in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, up from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are decreasing,” stated a senior researcher participating in the study. “That gap is widening and creates a significant issue. Consequently, PHEVs emit almost as much as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Analysts attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in electric power compared to total distance. They found that just a quarter of travel was completed in electric mode, while official assumptions suggested over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than lab projections. That occurred because EV motors were insufficiently powerful enough to function alone, resulting to combustion motors using fossil fuels for nearly one-third of the distance completed in electric mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output enabled four large automaker companies to escape more than €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 more annually in running costs than would be estimated under lab conditions.

“The bold claims that automakers often promote about their PHEV vehicles are clearly far from 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. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Policy Debate and Automotive Lobbying

Plug-in hybrid cars have recently been drawn again into political discussions as carmakers have lobbied the European Union to relax CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the automotive industry and opposition from EU countries with large automotive manufacturing.

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

An independent energy economics specialist, who was not involved with the study, described the analysis a “highly valuable addition” after years in which segments of the car industry claimed there was insufficient data to properly evaluate actual CO2 output.

“These findings show, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel vehicles,” they stated. “Any regulatory changes regarding PHEVs should be implemented with extreme caution and considering that evidence.”