Plug-in Hybrid electric Cars Emit Nearly as Much as Petrol Vehicles, Report Reveals

Plug-in hybrid cars produce almost 5x more planet-heating pollution than official data show, according to a recent analysis.

Growing Gap In Lab and Real-World Emissions

Statistics reveals that PHEVs emit only 19% less CO₂ than conventional gas and diesel vehicles, based on analysis conducted by a advocacy organization. This contrasts significantly with lab estimates, which assumed a three-quarters reduction in pollution.

Analysts studied data from onboard energy use monitors of 800,000 vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are decreasing,” stated a senior analyst participating in the study. “This gap is widening and poses a significant problem. As a result, PHEVs pollute almost as much as petrol vehicles.”

Key Factors Driving the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “utility factor” – the percentage of kilometers travelled in electric power relative to total mileage. They determined that only 27% of driving was completed in electric mode, while official assumptions assumed 84%.

Even, when running in electric mode, emission amounts were significantly higher than lab estimates. That happened because electric motors were not strong sufficient to function independently, leading to combustion motors using gasoline for almost a third of the travel covered in EV mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV CO2 output allowed four major automaker groups to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would pay approximately €500 more annually in operating expenses than is assumed under lab conditions.

“The strong statements that manufacturers often promote about their PHEV cars are obviously way off the truth,” stated a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and running costs.”

Policy Debate and Industry Lobbying

Hybrid cars have recently been brought back into policy debates as carmakers have lobbied the European Union to relax CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive industry and resistance from member states with large automotive industries.

Several senior officials have suggested plug-in hybrids as a potential “compromise” option to introduce in the legislation.

An external energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful addition” after a long period in which parts of the automotive sector argued there was too little information to properly assess real-world emissions.

“These findings show, without question, that the difference between lab and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or diesel vehicles,” they said. “All policy adjustments concerning PHEVs should be implemented with utmost caution and in the light of that data.”