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

Plug-in hybrid electric vehicles emit almost 5x more planet-heating emissions than official figures indicate, as per a new analysis.

Widening Discrepancy In Official and Actual Emissions

Data reveals that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, based on research carried out by a non-profit organization. This differs sharply with laboratory estimates, which suggested a 75% reduction in emissions.

Researchers examined information from in-vehicle energy use meters of 800,000 vehicles sold in Europe from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official figures, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior analyst involved in the study. “This discrepancy is widening and creates a significant issue. As a result, PHEVs emit almost as heavily as gasoline cars.”

Primary Factors Driving the Emissions Gap

Analysts attributed most of the gap to overestimates of the “electric driving share” – the percentage of kilometers driven in battery power relative to overall mileage. The team determined that just a quarter of driving was completed in EV mode, whereas official assumptions assumed 84%.

Even, when running in EV mode, pollution amounts were well above lab estimates. That occurred because electric motors were not strong sufficient to function independently, leading to combustion motors burning fossil fuels for almost one-third of the travel covered in electric mode.

Policy and Financial Consequences

Based on estimates, the lowballing of PHEV CO2 output enabled four large carmaker companies to escape more than €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 extra per year in running expenses than would be assumed under lab conditions.

“The strong statements that manufacturers often promote about their PHEV vehicles are obviously far from the truth,” stated a transport analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy use, CO₂ emissions, and operating expenses.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have recently been drawn back into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A planned prohibition on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive industry and opposition from EU countries with large automotive industries.

Several senior politicians have proposed PHEVs as a possible “compromise” option to introduce in the legislation.

An independent energy policy expert, who was unaffiliated with the study, described the analysis a “very useful addition” after a long period in which parts of the automotive sector claimed there was too little information to accurately assess real-world CO2 output.

“The results show, without question, that the gap in official and actual PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or conventional vehicles,” they said. “All policy changes regarding PHEVs should be made with utmost caution and considering this evidence.”