Plug in Hybrid Vehicles Pollute Nearly as Much as Petrol Vehicles, Report Reveals

PHEVs produce almost five times more global warming emissions than lab-reported data show, according to a recent analysis.

Growing Gap In Lab and Real-World Emissions

Data shows that PHEVs emit only 19% lower CO₂ than traditional gas and diesel cars, according to research conducted by a advocacy group. This differs sharply with lab estimates, which assumed a 75% reduction in pollution.

Researchers examined information from onboard energy use monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” stated a senior analyst participating in the report. “This gap is growing and creates a serious problem. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Factors Driving the Discrepancy

Analysts linked the majority of the difference to inflated estimates of the “electric driving share” – the ratio of miles travelled in battery power relative to overall distance. They found that just 27% of driving was done in EV mode, whereas lab estimates suggested 84%.

Even, when operating in electric mode, pollution amounts were significantly higher than lab projections. That happened because electric motors were insufficiently powerful enough to function alone, leading to engines burning fossil fuels for almost one-third of the distance completed in electric mode.

Regulatory and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output allowed four large automaker groups to avoid over €5bn in penalties between 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 more annually in operating expenses than would be assumed under laboratory conditions.

“The bold statements that manufacturers like to make about their PHEV cars are obviously way off the truth,” stated a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly improved than regular petrol and diesel cars in terms of fuel consumption, CO₂ production, and operating expenses.”

Political Debate and Industry Pressure

Plug-in hybrid cars have recently been brought back into political discussions as automakers have pressed the EU to weaken CO₂ targets. A proposed ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive industry and opposition from EU countries with significant automotive industries.

Some high-level politicians have proposed PHEVs as a possible “flexibility” solution to introduce in the legislation.

An external energy economics expert, who was not involved with the study, described the analysis a “highly valuable addition” after years in which segments of the car industry argued there was insufficient data to properly assess real-world emissions.

“These findings show, beyond any doubt, that the gap between lab and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional cars,” they stated. “All policy changes regarding PHEVs should be made with utmost caution and considering this evidence.”