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PHEVs release almost 5x more global warming pollution than lab-reported data show, as per a recent analysis.

Widening Discrepancy Between Official and Actual Emissions

Data reveals that PHEVs emit just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a advocacy group. That contrasts significantly with laboratory estimates, which suggested a three-quarters reduction in pollution.

Researchers examined data from in-vehicle energy use meters of 800,000 cars registered in Europe between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, up from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported figures are decreasing,” said a lead researcher participating in the study. “That discrepancy is widening and poses a significant issue. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Primary Factors Behind the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric mode relative to overall distance. The team determined that only 27% of driving was completed in electric mode, while official estimates suggested 84%.

Additionally, when running in EV mode, emission amounts were significantly higher than official projections. That occurred because electric motors were insufficiently powerful enough to function alone, resulting to engines using fossil fuels for nearly a third of the travel covered in EV mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV CO2 output enabled several large automaker groups to escape over €5bn in fines from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs would pay about €500 more annually in operating expenses than would be assumed under laboratory tests.

“The strong claims that automakers often promote about their plug-in hybrid vehicles are obviously far from the mark,” commented a automotive analyst. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the planet and saving money. In reality, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Industry Lobbying

Hybrid cars have recently been brought back into policy debates as automakers have lobbied the EU to weaken CO₂ targets. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large car manufacturing.

Several high-level politicians have proposed PHEVs as a possible “compromise” option to include in the legislation.

An external energy economics expert, who was not involved with the research, described the report a “very useful contribution” after years in which parts of the car sector claimed there was too little data to properly assess actual CO2 output.

“These findings show, without question, that the difference in official and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel cars,” they stated. “Any policy changes concerning PHEVs should be made with utmost care and in the light of this data.”