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Plug-in hybrid cars emit nearly five times more planet-heating emissions than official figures show, as per a new report.

Widening Discrepancy Between Official and Actual Emissions

Statistics shows that PHEVs release only one-fifth less CO₂ than conventional gas and diesel vehicles, based on research carried out by a non-profit organization. This contrasts significantly with laboratory estimates, which assumed a three-quarters reduction in pollution.

Researchers examined information from in-vehicle energy use meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found 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 figures are decreasing,” stated a lead analyst involved in the report. “That discrepancy is widening and poses a significant issue. As a result, PHEVs emit almost as heavily as petrol cars.”

Primary Reasons Behind the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the ratio of miles driven in battery power compared to total mileage. The team found that just a quarter of travel was done in electric mode, while official assumptions assumed over four-fifths.

Additionally, when operating in electric mode, pollution amounts were well above lab projections. That occurred because electric motors were not strong sufficient to operate independently, resulting to combustion motors burning fossil fuels for almost a third of the travel covered in electric mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV CO2 output enabled several large automaker companies to escape more than €5bn in fines between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs could pay about €500 more per year in running costs than is assumed under lab tests.

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly way off the truth,” commented a automotive expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and running costs.”

Policy Discussion and Automotive Pressure

Hybrid vehicles have recently been brought again into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car industry and resistance from member states with large automotive industries.

Some senior politicians have suggested PHEVs as a possible “flexibility” solution to introduce in the legislation.

One independent energy policy specialist, who was not involved with the research, described the analysis a “very useful addition” after years in which segments of the automotive industry claimed there was insufficient information to properly evaluate actual CO2 output.

“The results demonstrate, without question, that the gap in official and actual PHEV energy use and CO₂ output is significantly greater than for petrol or conventional cars,” they stated. “Any regulatory adjustments regarding PHEVs should be made with extreme caution and in the light of this evidence.”