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PHEVs produce nearly five times more global warming emissions than official data show, as per a new analysis.

Growing Discrepancy Between Lab and Real-World Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a advocacy organization. That contrasts significantly with lab estimates, which assumed a 75% decrease in emissions.

Analysts studied data from onboard energy use meters of 800,000 vehicles sold in Europe between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while official figures are decreasing,” stated a lead analyst participating in the study. “This discrepancy is growing and creates a significant problem. As a result, PHEVs pollute nearly as much as gasoline cars.”

Key Factors Driving the Emissions Gap

Researchers attributed the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric power compared to total distance. The team found that just a quarter of driving was done in EV mode, whereas official assumptions assumed 84%.

Additionally, when operating in electric mode, emission levels were significantly higher than official projections. This occurred because electric motors were not strong enough to function independently, leading to engines using fossil fuels for almost a third of the travel covered in EV mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV CO2 output enabled four large carmaker groups to avoid over €5bn in penalties between 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend approximately €500 more per year in operating expenses than is estimated under laboratory conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are obviously way off the truth,” stated a automotive expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Political Debate and Industry Lobbying

Plug-in hybrid vehicles have recently been drawn back into policy discussions as automakers have pressed the European Union to relax CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and resistance from member states with significant car industries.

Some high-level politicians have suggested PHEVs as a possible “flexibility” solution to include in the regulation.

One external energy economics specialist, who was unaffiliated with the research, described the analysis a “very useful addition” after years in which parts of the car industry claimed there was insufficient data to properly evaluate actual CO2 output.

“These findings demonstrate, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” they stated. “Any policy adjustments regarding PHEVs should be made with extreme caution and considering this data.”