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Plug-in hybrid cars release nearly 5x more global warming pollution than lab-reported data show, as per a recent report.

Widening Gap Between Official and Actual CO2 Output

Statistics reveals that PHEVs release just 19% less CO₂ than conventional gas and diesel cars, based on analysis carried out by a advocacy organization. That differs significantly with laboratory estimates, which assumed a 75% reduction in emissions.

Researchers studied data from in-vehicle energy use meters of eight hundred thousand cars registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while official emissions are decreasing,” stated a lead researcher involved in the report. “This discrepancy is widening and poses a significant issue. Consequently, PHEVs pollute almost as much as gasoline cars.”

Primary Factors Driving the Discrepancy

Analysts linked most of the difference to overestimates of the “utility factor” – the ratio of miles driven in electric mode relative to total distance. They determined that just a quarter of driving was done in electric mode, whereas lab assumptions assumed over four-fifths.

Even, when operating in electric mode, pollution levels were well above official projections. That happened because EV motors were insufficiently powerful enough to function alone, leading to engines burning fossil fuels for nearly a third of the travel completed in EV mode.

Policy and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output allowed several major carmaker companies to escape more than €5bn in fines between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 more per year in operating costs than is assumed under lab conditions.

“The bold claims that automakers often promote about their plug-in hybrid cars are obviously way off the mark,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the environment and cutting costs. Actually, PHEVs are little improved than standard petrol and diesel cars in terms of fuel use, CO₂ production, and running costs.”

Political Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn again into political debates as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on new internal combustion vehicles in 2035 has faced heavy lobbying from the car industry and opposition from EU countries with large car industries.

Some high-level politicians have suggested PHEVs as a potential “compromise” option to introduce in the legislation.

One independent energy economics expert, who was not involved with the research, called the analysis a “very useful contribution” after years in which parts of the automotive sector claimed there was too little information to properly assess real-world emissions.

“These findings show, beyond any doubt, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or diesel vehicles,” the expert stated. “All regulatory changes concerning PHEVs should be made with extreme caution and considering this data.”