🔗 Share this article

Plug-in hybrid cars release nearly 5x greater global warming emissions than lab-reported figures indicate, as per a new analysis.

Widening Gap In Official and Real-World CO2 Output

Data shows that PHEVs release only 19% lower CO₂ than traditional petrol and diesel cars, according to analysis conducted by a advocacy organization. That differs sharply with laboratory tests, which suggested a 75% reduction in emissions.

Analysts studied information from in-vehicle energy use monitors of 800,000 cars sold in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are falling,” said a lead analyst involved in the report. “That discrepancy is widening and poses a serious issue. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Behind the Emissions Gap

Analysts linked most of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in electric mode compared to total distance. They found that only 27% of travel was completed in EV mode, whereas lab assumptions suggested 84%.

Additionally, when running in electric mode, emission amounts were significantly higher than lab estimates. That occurred because electric motors were insufficiently powerful sufficient to operate alone, leading to engines burning fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Economic Implications

According to calculations, the underestimation of PHEV CO2 output enabled four large automaker companies to escape more than €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ standards.

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

“The bold statements that manufacturers often promote about their PHEV cars are clearly far from the truth,” commented a transport analyst. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been drawn again into policy debates as automakers have pressed the EU to relax CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with significant car industries.

Some high-level politicians have suggested plug-in hybrids as a possible “flexibility” option to include in the legislation.

One external energy economics expert, who was unaffiliated with the study, described the analysis a “very useful contribution” after years in which parts of the automotive sector argued there was insufficient information to properly evaluate real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or conventional cars,” they said. “All policy changes regarding PHEVs should be implemented with utmost caution and considering that data.”