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

Plug-in hybrid electric vehicles produce almost 5x greater planet-heating pollution than official figures show, as per a new analysis.

Growing Gap In Lab and Real-World CO2 Output

Statistics shows that PHEVs release just 19% lower CO₂ than conventional petrol and diesel vehicles, according to analysis conducted by a advocacy group. This contrasts sharply with laboratory tests, which assumed a three-quarters decrease in emissions.

Analysts examined data from in-vehicle energy use monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, up from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported figures are decreasing,” stated a lead researcher involved in the study. “This gap is growing and creates a significant problem. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Factors Behind the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric mode compared to overall mileage. The team found that only a quarter of driving was done in electric mode, while lab assumptions assumed over four-fifths.

Even, when running in electric mode, emission levels were well above lab estimates. This happened because electric motors were insufficiently powerful sufficient to operate alone, leading to combustion motors using fossil fuels for almost one-third of the travel completed in EV mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV emissions enabled several major carmaker groups to avoid over €5bn in fines from 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could spend about €500 extra annually in running expenses than is estimated under lab tests.

“The strong statements that manufacturers often promote about their PHEV vehicles are clearly way off the mark,” stated a automotive expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and operating costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been drawn again into political discussions as carmakers have lobbied the EU to weaken CO₂ targets. A planned ban on sales of new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with large car manufacturing.

Several high-level politicians have suggested plug-in hybrids as a possible “compromise” option to introduce in the regulation.

An independent energy policy expert, who was unaffiliated with the research, described the analysis a “very useful addition” after a long period in which parts of the automotive sector argued there was insufficient information to properly evaluate real-world emissions.

“The results demonstrate, beyond any doubt, that the gap in official and actual PHEV energy use and CO₂ output is significantly greater than for gasoline or diesel cars,” the expert stated. “Any policy changes concerning PHEVs should be implemented with extreme caution and considering this data.”