Plug in Hybrid electric Vehicles Emit Almost as Heavily as Gasoline Cars, Study Finds

PHEVs release nearly five times more planet-heating emissions than lab-reported data show, according to a recent analysis.

Growing Discrepancy Between Lab and Actual CO2 Output

Statistics shows that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel cars, according to research conducted by a advocacy organization. That differs significantly with laboratory tests, which suggested a three-quarters reduction in emissions.

Analysts examined data from onboard fuel consumption meters of eight hundred thousand vehicles sold in the EU from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, up from three and a half times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” stated a lead analyst involved in the report. “This discrepancy is widening and creates a significant issue. As a result, PHEVs pollute nearly as much as gasoline cars.”

Key Factors Behind the Emissions Gap

Researchers linked most of the gap to overestimates of the “utility factor” – the ratio of miles driven in battery mode relative to overall distance. The team found that only 27% of travel was completed in EV mode, while official estimates suggested over four-fifths.

Even, when running in EV mode, pollution levels were significantly higher than official projections. This occurred because electric motors were insufficiently powerful sufficient to function alone, leading to engines using gasoline for nearly one-third of the travel completed in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV emissions allowed four large carmaker companies to avoid over €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend about €500 more per year in running expenses than would be assumed under laboratory conditions.

“The bold claims that automakers often promote about their PHEV vehicles are obviously way off the truth,” commented a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly improved than regular gas and diesel cars in terms of fuel use, CO₂ production, and running costs.”

Policy Discussion and Industry Lobbying

Hybrid cars have lately been brought again into political debates as automakers have pressed the EU to relax CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the automotive industry and resistance from EU countries with large automotive industries.

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

An independent energy policy expert, who was not involved with the research, called the analysis a “very useful contribution” after a long period in which segments of the car industry argued there was insufficient data to accurately assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap between lab and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional cars,” the expert said. “All policy changes regarding PHEVs should be implemented with utmost care and in the light of this data.”