🔗 Share this article

Plug-in hybrid cars emit nearly five times more planet-heating emissions than official data indicate, according to a new report.

Growing Discrepancy In Lab and Actual Emissions

Statistics reveals that PHEVs emit just 19% less CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy organization. That differs significantly with lab tests, which suggested a 75% decrease in emissions.

Analysts examined information from in-vehicle energy use meters of eight hundred thousand cars sold in the EU between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while official figures are decreasing,” stated a lead analyst participating in the report. “That discrepancy is growing and poses a serious problem. Consequently, PHEVs pollute nearly as much as gasoline cars.”

Primary Reasons Behind the Discrepancy

Analysts attributed the majority of the difference to overestimates of the “utility factor” – the ratio of miles travelled in battery mode relative to total distance. The team found that just a quarter of travel was completed in EV mode, while official assumptions suggested 84%.

Additionally, when operating in EV mode, pollution amounts were well above lab estimates. That happened because electric motors were not strong sufficient to function independently, resulting to combustion motors burning fossil fuels for nearly a third of the distance covered in electric mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV CO2 output allowed four major automaker groups to avoid more than €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 extra per year in running expenses than would be assumed under laboratory tests.

“The bold claims that automakers like to make about their plug-in hybrid vehicles are clearly far from the truth,” commented a transport analyst. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and operating costs.”

Policy Debate and Industry Lobbying

Hybrid vehicles have lately been brought again into policy debates as automakers have lobbied the EU to weaken 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 member states with significant car manufacturing.

Several high-level officials have suggested plug-in hybrids as a possible “flexibility” solution to introduce in the legislation.

An independent energy economics expert, who was not involved with the research, described the analysis a “highly valuable contribution” after a long period in which segments of the car industry claimed there was insufficient information to properly assess actual CO2 output.

“The results demonstrate, without question, that the gap between official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or diesel cars,” the expert stated. “All regulatory adjustments concerning PHEVs should be implemented with extreme caution and considering that data.”