Plug-in Hybrid Cars Emit Nearly as Much as Petrol Cars, Study Finds

Plug-in hybrid cars emit almost five times more planet-heating emissions than official data indicate, as per a recent report.

Growing Discrepancy In Official and Real-World Emissions

Statistics shows that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel vehicles, according to analysis conducted by a non-profit group. That contrasts significantly with lab tests, which assumed a 75% reduction in emissions.

Researchers examined data from in-vehicle fuel consumption monitors of eight hundred thousand vehicles sold in Europe from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while official emissions are falling,” stated a senior researcher involved in the report. “This discrepancy is growing and poses a significant issue. As a result, PHEVs emit almost as heavily as petrol cars.”

Primary Reasons Driving the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the percentage of miles travelled in electric power compared to overall mileage. The team determined that only 27% of driving was done in EV mode, whereas official assumptions suggested over four-fifths.

Even, when running in electric mode, emission amounts were well above lab projections. This occurred because EV motors were not strong sufficient to operate alone, resulting to combustion motors burning fossil fuels for nearly a third of the travel covered in electric mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV emissions enabled four large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs could pay approximately €500 more per year in running expenses than would be estimated under laboratory tests.

“The strong statements that automakers often promote about their plug-in hybrid vehicles are clearly far from the truth,” commented a automotive analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than regular gas and diesel cars in terms of fuel consumption, CO₂ production, and operating costs.”

Political Discussion and Automotive Pressure

Hybrid vehicles have recently been brought back into policy debates as carmakers have lobbied the EU to weaken CO₂ targets. A proposed prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with significant car industries.

Several senior politicians have proposed PHEVs as a potential “flexibility” solution to include in the regulation.

One independent energy policy specialist, who was unaffiliated with the research, called the report a “highly valuable addition” after years in which segments of the automotive industry argued there was too little data to accurately evaluate actual emissions.

“The results show, without question, that the gap between lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or conventional cars,” they stated. “All regulatory adjustments regarding PHEVs should be implemented with extreme caution and in the light of that data.”