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PHEVs release almost five times greater global warming emissions than official data show, as per a new analysis.

Widening Gap In Lab and Real-World Emissions

Statistics shows that PHEVs release only one-fifth lower CO₂ than conventional gas and diesel vehicles, based on research conducted by a non-profit group. That contrasts significantly with laboratory tests, which suggested a three-quarters decrease in emissions.

Researchers examined information from in-vehicle energy use meters of eight hundred thousand vehicles sold in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” said a lead analyst involved in the study. “This gap is growing and creates a serious issue. Consequently, PHEVs pollute nearly as much as petrol vehicles.”

Primary Reasons Driving the Discrepancy

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the ratio of miles driven in electric mode relative to overall mileage. The team found that only a quarter of driving was completed in electric mode, whereas official estimates suggested 84%.

Additionally, when operating in EV mode, pollution amounts were well above official estimates. That occurred because electric motors were not strong enough to function alone, leading to engines using fossil fuels for nearly a third of the distance completed in electric mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV emissions allowed four major automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 more annually in running expenses than is estimated under laboratory tests.

“The strong statements that automakers like to make about their PHEV vehicles are clearly way off the mark,” stated a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are little better than regular petrol and diesel cars in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have lately been brought again into political debates as carmakers have pressed the European Union to relax CO₂ standards. A planned prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive sector and opposition from member states with significant car industries.

Some high-level officials have proposed plug-in hybrids as a possible “compromise” solution to introduce in the regulation.

One external energy economics expert, who was unaffiliated with the research, called the analysis a “highly valuable contribution” after years in which segments of the car sector claimed there was insufficient data to properly assess actual CO2 output.

“These findings show, without question, that the difference in lab and real-world PHEV energy use and CO₂ output is much, much larger than for gasoline or conventional vehicles,” the expert stated. “All regulatory changes concerning PHEVs should be made with extreme care and considering that data.”