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PHEVs produce almost five times more planet-heating pollution than official data indicate, as per a recent analysis.

Growing Discrepancy Between Official and Real-World CO2 Output

Statistics shows that PHEVs release only one-fifth less CO₂ than traditional petrol and diesel vehicles, based on analysis conducted by a advocacy group. This contrasts significantly with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts studied information from in-vehicle energy use monitors of 800,000 cars registered in Europe between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” said a senior analyst involved in the report. “This gap is widening and poses a significant problem. Consequently, PHEVs pollute nearly as heavily as gasoline vehicles.”

Key Reasons Behind the Emissions Gap

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in battery mode relative to overall mileage. They determined that just 27% of travel was done in EV mode, whereas official estimates assumed over four-fifths.

Even, when operating in EV mode, emission amounts were significantly higher than lab estimates. This occurred because EV motors were not strong sufficient to operate alone, resulting to combustion motors burning gasoline for nearly a third of the travel covered in electric mode.

Policy and Financial Implications

Based on estimates, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs could spend about €500 more annually in running costs than is estimated under lab tests.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are obviously far from the truth,” stated a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and running expenses.”

Policy Debate and Industry Pressure

Hybrid vehicles have recently been brought back into policy discussions as automakers have lobbied the EU to relax CO₂ targets. A planned prohibition on sales of new combustion engine cars in 2035 has faced intense lobbying from the automotive sector and opposition from member states with significant automotive industries.

Several high-level officials have proposed PHEVs as a possible “compromise” solution to include in the legislation.

One external energy economics expert, who was not involved with the research, called the analysis a “highly valuable addition” after a long period in which segments of the automotive industry claimed there was too little information to accurately evaluate actual CO2 output.

“These findings demonstrate, beyond any doubt, that the gap between official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or diesel vehicles,” the expert said. “All regulatory adjustments regarding PHEVs should be made with extreme care and in the light of that data.”