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PHEVs produce almost five times greater global warming pollution than official figures indicate, as per a new report.

Growing Discrepancy In Lab and Actual Emissions

Data reveals that PHEVs emit just one-fifth lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a advocacy organization. This contrasts significantly with laboratory tests, which suggested a three-quarters reduction in emissions.

Analysts studied information from onboard energy use monitors of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are falling,” stated a senior researcher participating in the study. “That gap is widening and creates a serious issue. As a result, PHEVs pollute almost as much as gasoline cars.”

Key Factors Behind the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric power relative to total distance. The team determined that only 27% of travel was done in EV mode, while official estimates assumed over four-fifths.

Additionally, when running in EV mode, emission amounts were well above official projections. This occurred because electric motors were not strong enough to function independently, resulting to engines using fossil fuels for nearly one-third of the travel completed in electric mode.

Policy and Financial Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled several major carmaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs would pay approximately €500 extra annually in operating expenses than is estimated under laboratory conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are obviously way off the mark,” commented a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have lately been brought back into policy debates as carmakers have lobbied the European Union to weaken CO₂ targets. A proposed prohibition on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive industry and opposition from EU countries with significant car industries.

Some senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to include in the legislation.

One external energy policy specialist, who was unaffiliated with the research, described the analysis a “very useful contribution” after a long period in which parts of the automotive industry argued there was insufficient data to accurately evaluate real-world CO2 output.

“The results show, beyond any doubt, that the difference between official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional cars,” the expert said. “All policy adjustments regarding PHEVs should be implemented with extreme care and considering that data.”