Plug in Hybrid Vehicles Emit Almost as Much as Gasoline Cars, Report Finds

Plug-in hybrid electric vehicles produce almost 5x greater planet-heating emissions than lab-reported data show, as per a new analysis.

Growing Gap In Official and Real-World Emissions

Statistics shows that PHEVs release just 19% lower CO₂ than traditional gas and diesel vehicles, according to research carried out by a advocacy group. This contrasts significantly with laboratory estimates, which suggested a three-quarters reduction in pollution.

Analysts studied data from in-vehicle energy use monitors of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported figures are falling,” said a lead analyst involved in the study. “That discrepancy is growing and poses a significant problem. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked most of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in electric mode compared to overall distance. The team found that just a quarter of driving was done in electric mode, whereas lab assumptions assumed 84%.

Even, when operating in electric mode, emission levels were significantly higher than lab projections. This occurred because electric motors were not strong sufficient to operate independently, leading to engines burning gasoline for nearly a third of the distance covered in EV mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV emissions allowed several large automaker groups to escape more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could pay about €500 more per year in operating costs than is assumed under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid vehicles are clearly way off the truth,” stated a transport analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly better than standard gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Policy Debate and Automotive Pressure

Hybrid cars have lately been drawn back into political discussions as automakers have lobbied the EU to relax CO₂ targets. A planned ban on new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and resistance from member states with large car manufacturing.

Several senior officials have proposed plug-in hybrids as a possible “compromise” solution to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which parts of the automotive sector argued there was insufficient information to properly assess actual CO2 output.

“These findings show, beyond any doubt, that the difference between lab and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or diesel cars,” they stated. “Any regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering that evidence.”