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Plug-in hybrid cars produce nearly 5x more planet-heating emissions than official figures show, according to a recent analysis.

Widening Gap In Lab and Actual CO2 Output

Statistics shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel cars, based on analysis conducted by a non-profit group. This contrasts significantly with laboratory estimates, which suggested a three-quarters decrease in emissions.

Analysts studied information from onboard fuel consumption monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Real-world emissions are rising, while official figures are falling,” stated a senior researcher participating in the report. “That discrepancy is widening and creates a serious problem. As a result, PHEVs emit almost as much as petrol cars.”

Key Reasons Behind the Emissions Gap

Researchers attributed most of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in battery mode relative to overall mileage. The team found that just 27% of driving was done in electric mode, while official estimates suggested over four-fifths.

Even, when operating in electric mode, pollution amounts were significantly higher than lab estimates. That occurred because electric motors were insufficiently powerful sufficient to operate alone, resulting to engines using fossil fuels for nearly a third of the travel covered in electric mode.

Regulatory and Financial Implications

Based on estimates, the underestimation of PHEV CO2 output allowed four large automaker companies to escape more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 more per year in operating expenses than would be estimated under lab tests.

“The bold statements that automakers like to make about their plug-in hybrid cars are obviously way off the mark,” commented a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the planet and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Pressure

Hybrid cars have recently been drawn back into political discussions as carmakers have pressed the European Union to relax CO₂ standards. A proposed prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car industry and opposition from member states with large car manufacturing.

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

An external energy policy expert, who was unaffiliated with the research, described the report a “highly valuable addition” after years in which parts of the car industry claimed there was too little data to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap between lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” they stated. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of that evidence.”