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Plug-in hybrid electric vehicles release almost 5x greater global warming emissions than lab-reported data show, as per a recent analysis.

Growing Discrepancy Between Lab and Real-World Emissions

Statistics reveals that PHEVs release only 19% less CO₂ than conventional gas and diesel vehicles, based on research carried out by a advocacy organization. That differs sharply with laboratory estimates, which suggested a 75% reduction in pollution.

Analysts examined data from in-vehicle energy use meters of 800,000 cars sold in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while official emissions are decreasing,” stated a senior analyst participating in the report. “That discrepancy is growing and creates a significant issue. Consequently, PHEVs emit almost as heavily as gasoline cars.”

Key Reasons Driving the Emissions Gap

Analysts linked most of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in battery mode compared to total mileage. They found that only a quarter of driving was done in EV mode, whereas official estimates suggested over four-fifths.

Even, when running in electric mode, emission levels were well above official projections. This occurred because EV motors were insufficiently powerful enough to function alone, leading to combustion motors using fossil fuels for nearly one-third of the travel completed in electric mode.

Policy and Economic Consequences

According to estimates, the underestimation of PHEV emissions enabled four major automaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ targets.

Additionally, drivers of PHEVs would spend about €500 more annually in operating costs than is assumed under laboratory conditions.

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly way off the mark,” commented a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and running expenses.”

Policy Discussion and Automotive Pressure

Plug-in hybrid vehicles have recently been brought again into political debates as carmakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced intense pressure from the car sector and resistance from member states with significant car manufacturing.

Several senior politicians have proposed plug-in hybrids as a potential “compromise” solution to introduce in the legislation.

One independent energy economics expert, who was unaffiliated with the research, described the report a “very useful contribution” after a long period in which segments of the car industry argued there was insufficient information to properly assess actual CO2 output.

“The results show, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional vehicles,” the expert said. “All policy changes concerning PHEVs should be implemented with utmost care and in the light of that evidence.”