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Plug-in hybrid electric vehicles release nearly 5x greater planet-heating emissions than lab-reported data indicate, as per a new analysis.

Widening Discrepancy Between Official and Actual CO2 Output

Statistics reveals that PHEVs emit only 19% less CO₂ than traditional gas and diesel cars, according to analysis carried out by a advocacy group. This differs significantly with laboratory estimates, which assumed a 75% decrease in emissions.

Analysts studied information from in-vehicle fuel consumption monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are decreasing,” stated a lead analyst involved in the report. “This gap is widening and poses a significant issue. As a result, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric mode relative to total distance. They found that just 27% of driving was done in electric mode, whereas lab estimates assumed over four-fifths.

Additionally, when running in EV mode, emission amounts were well above official projections. That occurred because electric motors were not strong sufficient to function independently, resulting to engines burning fossil fuels for nearly a third of the distance covered in electric mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV CO2 output enabled four large automaker companies to escape over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 more per year in operating costs than is estimated under lab conditions.

“The strong statements that manufacturers often promote about their PHEV cars are obviously far from the truth,” stated a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel consumption, CO₂ production, and running expenses.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been brought back into political debates as carmakers have pressed the European Union to relax CO₂ standards. A proposed prohibition on new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and opposition from member states with significant automotive manufacturing.

Some senior politicians have suggested plug-in hybrids as a possible “compromise” option to include in the regulation.

One independent energy policy specialist, who was unaffiliated with the research, called the report a “highly valuable addition” after years in which segments of the car sector argued there was too little data to properly evaluate actual CO2 output.

“These findings show, without question, that the difference between official and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or conventional vehicles,” the expert said. “All regulatory changes regarding PHEVs should be made with extreme care and in the light of this data.”