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PHEVs emit nearly 5x greater planet-heating pollution than official figures indicate, as per a new analysis.

Widening Gap In Official and Real-World Emissions

Statistics reveals that PHEVs release only 19% lower CO₂ than traditional petrol and diesel vehicles, according to analysis conducted by a non-profit group. That contrasts sharply with lab estimates, which assumed a three-quarters reduction in pollution.

Analysts studied data from in-vehicle fuel consumption monitors of eight hundred thousand vehicles sold in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, up from 3.5 times in 2021.

“Real-world emissions are rising, while official emissions are decreasing,” stated a senior researcher participating in the study. “That gap is growing and creates a significant problem. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Primary Factors Driving the Discrepancy

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers driven in electric mode relative to overall mileage. They determined that just a quarter of driving was done in EV mode, while official assumptions assumed 84%.

Even, when operating in electric mode, pollution amounts were significantly higher than official projections. This occurred because electric motors were not strong sufficient to operate alone, leading to combustion motors using fossil fuels for almost one-third of the distance covered in electric mode.

Policy and Financial Implications

According to estimates, the lowballing of PHEV CO2 output allowed several large automaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ targets.

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

“The bold statements that automakers often promote about their PHEV vehicles are clearly way off the truth,” stated a transport expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of energy use, CO₂ emissions, and operating expenses.”

Policy Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought back into policy debates as carmakers have pressed the EU to relax CO₂ targets. A proposed prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the car sector and opposition from EU countries with significant car industries.

Some high-level officials have suggested plug-in hybrids as a possible “compromise” option to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which parts of the automotive industry claimed there was insufficient information to properly assess actual emissions.

“The results demonstrate, without question, that the difference between official and actual PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional cars,” the expert said. “Any policy changes regarding PHEVs should be implemented with utmost care and in the light of that data.”