🔗 Share this article

Plug-in hybrid electric vehicles produce almost five times greater global warming emissions than lab-reported figures indicate, according to a recent analysis.

Growing Gap Between Lab and Actual CO2 Output

Statistics shows that PHEVs release just 19% lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a advocacy group. This contrasts sharply with lab estimates, which assumed a 75% reduction in emissions.

Researchers studied information from in-vehicle fuel consumption 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 figures, up from three and a half times in 2021.

“Actual emissions are rising, while official figures are falling,” stated a lead analyst participating in the report. “This gap is growing and poses a significant issue. Consequently, PHEVs emit almost as much as petrol vehicles.”

Key Reasons Behind the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles driven in battery power relative to total mileage. They found that only 27% of driving was done in electric mode, while lab estimates assumed 84%.

Additionally, when running in electric mode, pollution amounts were significantly higher than lab estimates. This happened because electric motors were not strong sufficient to function alone, leading to engines burning fossil fuels for almost one-third of the distance covered in EV mode.

Policy and Financial Implications

According to estimates, the underestimation of PHEV emissions allowed several major automaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would pay approximately €500 more per year in running expenses than would be assumed under laboratory tests.

“The bold claims that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the truth,” commented a automotive analyst. “Buyers 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 fuel consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Industry Pressure

Hybrid vehicles have recently been drawn back into political discussions as automakers have pressed the European Union to relax CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced intense pressure from the automotive industry and resistance from EU countries with large automotive industries.

Several high-level officials have suggested PHEVs as a potential “compromise” option to introduce in the legislation.

One external energy economics expert, who was unaffiliated with the research, called the analysis a “very useful addition” after years in which parts of the automotive sector argued there was insufficient data to properly evaluate real-world emissions.

“The results demonstrate, beyond any doubt, that the difference in official and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or diesel cars,” the expert stated. “Any policy changes regarding PHEVs should be implemented with extreme caution and in the light of this data.”