🔗 Share this article

Plug-in hybrid electric vehicles release nearly 5x more global warming emissions than official data show, as per a new analysis.

Growing Discrepancy In Lab and Real-World CO2 Output

Data shows that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel vehicles, according to analysis carried out by a advocacy group. That contrasts sharply with laboratory estimates, which suggested a 75% decrease in emissions.

Analysts examined information from in-vehicle fuel consumption meters of 800,000 cars registered in Europe between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, up from three and a half times in 2021.

“Actual emissions are rising, while official emissions are falling,” stated a lead analyst participating in the report. “This gap is growing and creates a significant problem. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the ratio of miles travelled in battery mode relative to total distance. The team determined that just a quarter of driving was completed in EV mode, whereas lab estimates assumed 84%.

Additionally, when running in EV mode, emission levels were significantly higher than official projections. That occurred because electric motors were insufficiently powerful enough to operate alone, leading to engines using fossil fuels for almost a third of the travel completed in electric mode.

Policy and Financial Implications

According to estimates, the underestimation of PHEV emissions enabled several major carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would pay approximately €500 more per year in operating expenses than is assumed under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are obviously far from the truth,” commented a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and saving money. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Debate and Automotive Pressure

Plug-in hybrid cars have lately been drawn back into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced heavy lobbying from the car sector and opposition from member states with large car industries.

Several high-level officials have proposed PHEVs as a potential “compromise” solution to include in the regulation.

One independent energy policy specialist, who was not involved with the research, described the analysis a “highly valuable contribution” after a long period in which segments of the car sector argued there was insufficient data to accurately assess real-world emissions.

“These findings show, beyond any doubt, that the difference in official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel cars,” the expert said. “All policy adjustments regarding PHEVs should be made with utmost caution and considering this evidence.”