Plug-in Hybrid Cars Pollute Almost as Much as Petrol Cars, Report Finds

Plug-in hybrid cars emit almost five times more global warming pollution than lab-reported figures show, according to a recent report.

Widening Discrepancy In Official and Actual Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a advocacy organization. That contrasts sharply with laboratory estimates, which assumed a 75% reduction in emissions.

Analysts 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 real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Actual emissions are rising, while official figures are falling,” stated a senior researcher participating in the report. “This discrepancy is growing and creates a serious issue. Consequently, PHEVs emit nearly as heavily as petrol cars.”

Key Factors Behind the Discrepancy

Analysts linked most of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to overall distance. They found that just a quarter of travel was done in electric mode, whereas lab estimates assumed 84%.

Additionally, when running in electric mode, pollution amounts were well above official projections. This happened because electric motors were not strong enough to operate alone, resulting to engines using fossil fuels for almost a third of the distance completed in electric mode.

Regulatory and Financial Implications

Based on estimates, the lowballing of PHEV emissions allowed four major carmaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend about €500 extra per year in running expenses than is assumed under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the truth,” stated a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel use, CO₂ emissions, and operating costs.”

Political Discussion and Industry Pressure

Hybrid vehicles have recently been brought again into political debates as carmakers have lobbied the European Union to weaken CO₂ targets. A proposed ban on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from member states with large car manufacturing.

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

One independent energy policy expert, who was unaffiliated with the research, called the report a “highly valuable contribution” after years in which parts of the automotive industry argued there was too little data to properly assess real-world emissions.

“These findings demonstrate, without question, that the difference between lab and actual PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” they stated. “All policy changes regarding PHEVs should be implemented with extreme care and considering this data.”