🔗 Share this article

Plug-in hybrid electric vehicles release almost five times more global warming emissions than lab-reported data show, according to a new analysis.

Widening Discrepancy In Official and Real-World Emissions

Data shows that PHEVs emit just 19% lower CO₂ than conventional gas and diesel vehicles, based on analysis conducted by a non-profit group. This contrasts sharply with lab tests, which suggested a 75% reduction in pollution.

Analysts studied information from onboard energy use monitors of 800,000 vehicles sold in Europe from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Actual emissions are rising, while lab-reported emissions are falling,” stated a senior researcher involved in the report. “That gap is widening and creates a serious problem. Consequently, PHEVs emit almost as much as gasoline cars.”

Primary Factors Driving the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles driven in electric mode compared to total mileage. The team determined that just 27% of travel was completed in electric mode, while lab estimates assumed over four-fifths.

Even, when operating in EV mode, emission amounts were well above lab estimates. That happened because EV motors were not strong sufficient to operate alone, resulting to engines burning fossil fuels for nearly one-third of the distance covered in electric mode.

Policy and Financial Consequences

According to estimates, the underestimation of PHEV CO2 output enabled several major carmaker groups to avoid more than €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 more annually in operating expenses than would be estimated under laboratory conditions.

“The strong claims that automakers often promote about their plug-in hybrid cars are obviously way off the truth,” commented a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Policy Debate and Automotive Pressure

Hybrid vehicles have recently been drawn back into policy debates as carmakers have pressed the European Union to weaken CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced heavy lobbying from the automotive sector and resistance from member states with significant car industries.

Some high-level officials have proposed PHEVs as a potential “compromise” option to include in the regulation.

An external energy economics expert, who was not involved with the research, described the analysis a “highly valuable addition” after years in which parts of the automotive industry argued there was too little information to properly evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap between lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional vehicles,” the expert said. “Any policy changes regarding PHEVs should be implemented with extreme caution and in the light of this evidence.”