🔗 Share this article

Plug-in hybrid electric vehicles release nearly 5x more planet-heating emissions than lab-reported data show, according to a new analysis.

Widening Discrepancy Between Lab and Real-World Emissions

Statistics shows that PHEVs emit just 19% less CO₂ than conventional gas and diesel vehicles, based on research conducted by a advocacy group. This contrasts sharply with laboratory estimates, which suggested a 75% reduction in pollution.

Analysts examined data from in-vehicle fuel consumption meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while official figures are decreasing,” said a lead analyst involved in the study. “That gap is widening and poses a serious issue. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts attributed the majority of the difference to inflated estimates of the “electric driving share” – the percentage of miles travelled in battery power relative to total mileage. The team determined that just a quarter of travel was completed in EV mode, while official estimates suggested over four-fifths.

Additionally, when operating in electric mode, emission levels were significantly higher than lab estimates. This happened because electric motors were insufficiently powerful enough to operate alone, leading to combustion motors using gasoline for almost one-third of the travel covered in electric mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV CO2 output enabled four large automaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 more per year in operating costs than is assumed under laboratory tests.

“The strong statements that automakers often promote about their PHEV cars are clearly far from the mark,” commented a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and saving money. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and running costs.”

Policy Debate and Industry Lobbying

Plug-in hybrid cars have lately been drawn again into policy debates as automakers have pressed the EU to weaken CO₂ targets. A proposed ban on sales of new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large automotive industries.

Some high-level politicians have suggested PHEVs as a potential “flexibility” option to include in the legislation.

An external energy economics expert, who was not involved with the study, called the analysis a “highly valuable addition” after a long period in which segments of the automotive sector claimed there was too little information to properly evaluate real-world emissions.

“The results show, without question, that the gap in lab and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional cars,” the expert said. “All regulatory changes regarding PHEVs should be made with extreme caution and in the light of this evidence.”