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Plug-in hybrid electric vehicles produce almost 5x more planet-heating emissions than lab-reported data indicate, as per a recent analysis.

Widening Discrepancy In Lab and Actual CO2 Output

Statistics reveals that PHEVs emit only 19% lower CO₂ than traditional petrol and diesel cars, based on analysis carried out by a advocacy group. That contrasts sharply with laboratory tests, which suggested a three-quarters decrease in pollution.

Researchers studied data from in-vehicle energy use monitors of 800,000 cars registered in the EU between 2021 and 2023. They 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 rising, while lab-reported emissions are decreasing,” stated a lead researcher involved in the report. “That gap is growing and poses a significant issue. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Key Factors Driving the Discrepancy

Analysts linked the majority of the difference to overestimates of the “utility factor” – the ratio of miles driven in electric mode relative to overall distance. They determined that just a quarter of travel was done in electric mode, whereas official assumptions suggested over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than official estimates. This occurred because electric motors were insufficiently powerful sufficient to function independently, resulting to combustion motors using gasoline for nearly one-third of the distance covered in EV mode.

Regulatory and Financial Implications

Based on estimates, the lowballing of PHEV emissions allowed several major automaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would spend about €500 extra per year in running costs than would be estimated under lab tests.

“The bold statements that manufacturers often promote about their plug-in hybrid cars are clearly far from the truth,” commented a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and operating expenses.”

Political Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been drawn back into political discussions as automakers have pressed the EU to relax CO₂ targets. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and opposition from EU countries with large car manufacturing.

Some senior officials have proposed PHEVs as a potential “compromise” solution to include in the legislation.

One external energy economics expert, who was not involved with the study, described the analysis a “very useful addition” after a long period in which segments of the automotive industry argued there was insufficient data to accurately evaluate actual emissions.

“These findings show, without question, that the difference in lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel vehicles,” the expert stated. “Any regulatory changes regarding PHEVs should be made with extreme caution and considering this data.”