Plug-in Hybrid electric Cars Emit Almost as Heavily as Petrol Cars, Study Finds

PHEVs release nearly 5x greater planet-heating pollution than official data indicate, as per a new analysis.

Growing Gap Between Lab and Real-World CO2 Output

Data reveals that PHEVs release only one-fifth lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a non-profit organization. That contrasts significantly with laboratory estimates, which assumed a three-quarters reduction in emissions.

Researchers examined data from onboard fuel consumption meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” stated a lead analyst involved in the report. “That discrepancy is growing and creates a significant problem. As a result, PHEVs pollute nearly as much as gasoline cars.”

Primary Reasons Behind the Discrepancy

Analysts linked most of the difference to overestimates of the “electric driving share” – the percentage of miles driven in electric power relative to total mileage. The team found that just 27% of travel was done in electric mode, whereas lab assumptions assumed over four-fifths.

Additionally, when operating in EV mode, pollution amounts were significantly higher than lab estimates. This occurred because EV motors were insufficiently powerful enough to function independently, resulting to combustion motors burning gasoline for nearly a third of the distance covered in electric mode.

Policy and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output enabled four large carmaker groups to avoid over €5bn in fines from 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay about €500 more per year in operating expenses than would be estimated under lab tests.

“The bold statements that automakers like to make about their PHEV vehicles are clearly way off the truth,” stated a transport expert. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are little better than regular gas and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have recently been brought back into political debates as automakers have lobbied the EU to weaken CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with large car manufacturing.

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

An external energy policy expert, who was unaffiliated with the study, described the report a “very useful contribution” after a long period in which parts of the car industry argued there was insufficient information to accurately assess real-world emissions.

“The results show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ output is significantly greater than for petrol or diesel vehicles,” they said. “All policy adjustments concerning PHEVs should be implemented with extreme care and in the light of that evidence.”