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Plug-in hybrid electric vehicles emit nearly five times more planet-heating emissions than official data indicate, as per a recent analysis.

Widening Discrepancy In Official and Actual CO2 Output

Statistics shows that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel cars, based on research carried out by a non-profit organization. This contrasts sharply with laboratory estimates, which assumed a three-quarters reduction in pollution.

Analysts examined information from in-vehicle fuel consumption monitors of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” stated a senior analyst participating in the study. “This gap is widening and creates a serious issue. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Key Reasons Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “utility factor” – the ratio of miles travelled in electric power relative to overall distance. The team found that only a quarter of travel was completed in electric mode, while lab estimates assumed 84%.

Additionally, when operating in electric mode, pollution amounts were well above lab projections. That occurred because EV motors were insufficiently powerful sufficient to function alone, leading to combustion motors using fossil fuels for almost a third of the travel covered in electric mode.

Policy and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed four large carmaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 more per year in running costs than would be estimated under lab conditions.

“The bold claims that automakers like to make about their plug-in hybrid cars are clearly far from the truth,” commented a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and saving costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Pressure

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

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

An independent energy economics expert, who was unaffiliated with the research, described the report a “highly valuable addition” after a long period in which parts of the automotive industry argued there was too little data to accurately assess real-world emissions.

“The results show, beyond any doubt, that the difference between lab and actual PHEV energy use and CO₂ emissions is significantly larger than for petrol or diesel cars,” the expert stated. “All policy adjustments concerning PHEVs should be made with extreme care and in the light of that data.”