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PHEVs release almost 5x greater planet-heating emissions than lab-reported figures indicate, as per a new analysis.

Growing Discrepancy Between Lab and Real-World CO2 Output

Data reveals that PHEVs emit just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on analysis carried out by a advocacy organization. That differs sharply with laboratory tests, which suggested a three-quarters decrease in emissions.

Analysts studied data from onboard fuel consumption monitors of 800,000 cars registered in Europe from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are falling,” said a senior analyst involved in the report. “That discrepancy is growing and creates a significant issue. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Key Factors Behind the Discrepancy

Researchers linked the majority of the difference to overestimates of the “utility factor” – the percentage of miles travelled in electric power relative to overall mileage. They determined that only 27% of driving was done in electric mode, while official estimates suggested over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than official projections. That happened because EV motors were insufficiently powerful sufficient to operate alone, resulting to engines burning fossil fuels for nearly one-third of the travel covered in EV mode.

Policy and Financial Consequences

According to calculations, the lowballing of PHEV emissions allowed several major carmaker companies to avoid over €5bn in fines between 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs would spend about €500 more annually in running expenses than is estimated under lab conditions.

“The strong claims that manufacturers often promote about their PHEV cars are clearly way off the truth,” commented a automotive analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Discussion and Industry Pressure

Hybrid cars have lately been brought back into political debates as automakers have pressed the EU to relax CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the automotive industry and resistance from member states with large automotive industries.

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

An external energy economics specialist, who was not involved with the study, called the analysis a “highly valuable contribution” after a long period in which segments of the automotive industry claimed there was too little information to accurately assess actual CO2 output.

“The results show, without question, that the difference between lab and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” the expert stated. “All regulatory changes regarding PHEVs should be made with extreme care and considering this data.”