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

PHEVs release almost 5x greater planet-heating emissions than official data indicate, according to a recent analysis.

Growing Discrepancy In Official and Actual Emissions

Data reveals that PHEVs emit only 19% lower CO₂ than traditional petrol and diesel cars, according to analysis conducted by a non-profit organization. That contrasts significantly with laboratory estimates, which assumed a 75% reduction in pollution.

Analysts studied data from in-vehicle fuel consumption meters of 800,000 cars sold in Europe between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” said a senior analyst participating in the study. “This discrepancy is widening and creates a serious problem. As a result, PHEVs emit almost as much as gasoline vehicles.”

Key Factors Driving the Discrepancy

Analysts linked most of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric power compared to total distance. The team determined that only a quarter of driving was completed in EV mode, while lab estimates suggested over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than official estimates. That occurred because EV motors were insufficiently powerful sufficient to function independently, leading to engines using fossil fuels for almost one-third of the distance covered in electric mode.

Regulatory and Financial Implications

Based on estimates, the lowballing of PHEV emissions allowed several large carmaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs could spend approximately €500 more annually in running costs than is assumed under laboratory conditions.

“The strong statements that manufacturers like to make about their PHEV cars are obviously way off the truth,” stated a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and saving costs. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and running expenses.”

Political Debate and Industry Pressure

Hybrid vehicles have recently been brought again into policy debates as carmakers have lobbied the European Union to relax CO₂ targets. A planned prohibition on sales of new combustion engine cars in 2035 has faced intense pressure from the automotive industry and resistance from member states with significant car manufacturing.

Some senior officials have proposed PHEVs as a potential “compromise” solution to introduce in the legislation.

One independent energy economics specialist, who was not involved with the study, described the analysis a “very useful addition” after a long period in which segments of the car industry argued there was too little information to accurately assess real-world CO2 output.

“These findings demonstrate, without question, that the difference between lab and actual PHEV energy use and CO₂ output is significantly greater than for gasoline or conventional cars,” they said. “All policy adjustments regarding PHEVs should be made with utmost care and considering this evidence.”