Plug-in Hybrid Vehicles Emit Nearly as Heavily as Gasoline Cars, Study Finds

PHEVs produce nearly 5x more planet-heating emissions than lab-reported figures indicate, as per a recent analysis.

Growing Gap Between Official and Real-World Emissions

Data reveals that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel cars, based on analysis carried out by a non-profit group. That contrasts significantly with lab tests, which assumed a 75% reduction in pollution.

Analysts examined data from onboard energy use monitors of eight hundred thousand vehicles sold in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from 3.5 times in 2021.

“Actual CO2 output are rising, while official figures are falling,” stated a lead analyst involved in the report. “That discrepancy is growing and poses a significant issue. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Primary Factors Driving the Discrepancy

Analysts attributed the majority of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in battery power compared to overall mileage. They found that only a quarter of driving was done in electric mode, whereas lab estimates assumed over four-fifths.

Even, when operating in EV mode, pollution amounts were well above official projections. That occurred because EV motors were insufficiently powerful enough to function independently, resulting to engines burning fossil fuels for nearly one-third of the distance completed in EV mode.

Policy and Economic Consequences

Based on estimates, the lowballing of PHEV CO2 output enabled several large carmaker groups to avoid more than €5bn in fines from 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend approximately €500 extra per year in running expenses than is estimated under lab conditions.

“The bold claims that automakers often promote about their PHEV cars are obviously way off the mark,” stated a transport analyst. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little improved than regular petrol and diesel vehicles in terms of energy use, CO₂ emissions, and operating expenses.”

Policy Discussion and Automotive Lobbying

Hybrid cars have lately been drawn back into political debates as carmakers have pressed the European Union to relax CO₂ targets. A proposed prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and opposition from member states with significant car manufacturing.

Several senior officials have suggested plug-in hybrids as a potential “flexibility” solution to include in the regulation.

An external energy economics expert, who was unaffiliated with the research, called the analysis a “very useful contribution” after years in which segments of the automotive sector argued there was too little information to properly evaluate actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel vehicles,” they stated. “All regulatory changes concerning PHEVs should be made with utmost care and considering this data.”