🔗 Share this article

PHEVs emit nearly 5x more planet-heating emissions than official figures show, as per a new analysis.

Growing Gap Between Lab and Real-World Emissions

Data shows that PHEVs emit just 19% lower CO₂ than traditional gas and diesel cars, according to research conducted by a non-profit organization. This contrasts significantly with lab estimates, which suggested a 75% decrease in emissions.

Researchers examined information from in-vehicle fuel consumption monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are falling,” said a lead researcher involved in the report. “That discrepancy is widening and creates a significant problem. As a result, PHEVs pollute almost as much as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked the majority of the difference to overestimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to overall distance. The team found that only a quarter of driving was completed in EV mode, while official assumptions assumed 84%.

Additionally, when running in EV mode, pollution amounts were significantly higher than lab projections. This happened because EV motors were insufficiently powerful sufficient to function alone, resulting to combustion motors burning fossil fuels for nearly a third of the distance completed in EV mode.

Regulatory and Financial Consequences

Based on estimates, the underestimation of PHEV emissions enabled four major carmaker groups to escape more than €5bn in fines from 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 extra annually in operating expenses than is assumed under lab conditions.

“The bold statements that manufacturers like to make about their PHEV vehicles are obviously far from the mark,” commented a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and cutting costs. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating costs.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have recently been drawn back into policy debates as automakers have pressed the European Union to weaken CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and opposition from member states with large car industries.

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

One independent energy policy expert, who was unaffiliated with the research, described the report a “highly valuable contribution” after a long period in which segments of the automotive sector argued there was too little data to accurately assess actual emissions.

“The results show, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or diesel vehicles,” the expert stated. “All policy changes concerning PHEVs should be made with extreme care and in the light of this data.”