🔗 Share this article

Plug-in hybrid electric vehicles emit nearly 5x more planet-heating pollution than official figures show, as per a new analysis.

Growing Gap Between Lab and Actual Emissions

Statistics reveals that PHEVs emit only one-fifth less CO₂ than traditional gas and diesel vehicles, according to research conducted by a non-profit group. That contrasts sharply with laboratory estimates, which suggested a 75% reduction in emissions.

Researchers examined information from in-vehicle energy use meters of eight hundred thousand vehicles registered in Europe between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” said a lead analyst participating in the study. “That discrepancy is growing and creates a serious problem. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the difference to inflated estimates of the “electric driving share” – the percentage of miles travelled in battery mode relative to total mileage. They found that only a quarter of travel was completed in electric mode, whereas lab assumptions suggested 84%.

Even, when operating in EV mode, emission amounts were significantly higher than official estimates. This occurred because electric motors were insufficiently powerful enough to operate alone, resulting to combustion motors using fossil fuels for nearly a third of the distance completed in electric mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output allowed several large automaker companies to escape over €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs would pay approximately €500 more annually in operating costs than would be assumed under laboratory conditions.

“The bold statements that manufacturers like to make about their PHEV vehicles are clearly far from the mark,” stated a transport expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy use, CO₂ production, and operating costs.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid vehicles have recently been drawn again into political discussions as carmakers have pressed the EU to weaken CO₂ standards. A planned prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the automotive industry and opposition from member states with significant automotive manufacturing.

Some senior officials have suggested PHEVs as a possible “compromise” solution to introduce in the regulation.

An independent energy economics specialist, who was unaffiliated with the study, described the report a “highly valuable addition” after years in which parts of the car industry claimed there was insufficient data to accurately assess real-world emissions.

“The results show, beyond any doubt, that the gap in lab and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or conventional cars,” they stated. “All regulatory adjustments concerning PHEVs should be made with extreme caution and considering this data.”