Plug in Hybrid electric Vehicles Emit Almost as Heavily as Petrol Cars, Study Finds

PHEVs release almost 5x more global warming pollution than official data indicate, according to a recent report.

Growing Discrepancy In Lab and Actual Emissions

Statistics shows that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a advocacy organization. This differs sharply with laboratory estimates, which suggested a 75% reduction in emissions.

Researchers examined data from onboard energy use monitors of 800,000 cars sold in the EU from 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are falling,” said a senior researcher involved in the study. “This gap is growing and poses a significant issue. Consequently, PHEVs emit nearly as much as petrol vehicles.”

Primary Factors Driving the Discrepancy

Analysts linked the majority of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery power compared to total distance. The team determined that just 27% of travel was done in electric mode, while lab assumptions assumed over four-fifths.

Additionally, when operating in EV mode, emission levels were significantly higher than official estimates. This happened because electric motors were not strong sufficient to operate independently, resulting to combustion motors burning gasoline for nearly a third of the distance completed in electric mode.

Policy and Financial Consequences

According to estimates, the lowballing of PHEV CO2 output enabled several major automaker companies to escape over €5bn in fines between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 more per year in running costs than is estimated under laboratory tests.

“The bold claims that manufacturers often promote about their plug-in hybrid vehicles are clearly far from the truth,” commented a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting money. In reality, PHEVs are only slightly better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and operating expenses.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been brought back into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced intense pressure from the car sector and opposition from EU countries with large car industries.

Some senior politicians have suggested plug-in hybrids as a potential “flexibility” option to include in the regulation.

An independent energy economics specialist, who was not involved with the research, called the report a “very useful addition” after years in which segments of the car sector argued there was too little data to properly evaluate actual emissions.

“The results show, without question, that the difference between official and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or diesel vehicles,” the expert said. “All regulatory adjustments concerning PHEVs should be made with extreme caution and in the light of that evidence.”