🔗 Share this article

Plug-in hybrid cars emit nearly 5x greater global warming pollution than official data show, according to a recent report.

Widening Discrepancy In Lab and Actual Emissions

Data shows that PHEVs release just one-fifth less CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a advocacy group. This contrasts significantly with lab tests, which assumed a 75% reduction in emissions.

Analysts examined data from in-vehicle fuel consumption meters of 800,000 vehicles registered in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are falling,” stated a senior researcher involved in the report. “That gap is growing and poses a significant issue. Consequently, PHEVs emit almost as heavily as petrol cars.”

Key Factors Driving the Emissions Gap

Researchers attributed most of the difference to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric power compared to total mileage. The team determined that only a quarter of travel was completed in electric mode, while official assumptions assumed 84%.

Even, when operating in electric mode, emission levels were well above official estimates. This happened because EV motors were not strong sufficient to operate alone, resulting to engines using fossil fuels for almost one-third of the travel completed in EV mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output allowed four major automaker groups to avoid more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay about €500 more per year in running expenses than is estimated under lab conditions.

“The strong statements that automakers like to make about their PHEV vehicles are clearly far from the truth,” commented a transport expert. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been brought back into policy debates as automakers have lobbied the European Union to relax CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the automotive industry and opposition from member states with significant car manufacturing.

Some high-level officials have suggested plug-in hybrids as a potential “compromise” solution to introduce in the legislation.

One independent energy economics specialist, who was unaffiliated with the research, called the report a “highly valuable contribution” after years in which parts of the automotive sector claimed there was insufficient data to properly evaluate actual emissions.

“The results show, beyond any doubt, that the gap between lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for petrol or diesel vehicles,” they stated. “All regulatory changes concerning PHEVs should be implemented with utmost caution and in the light of this data.”