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PHEVs produce nearly 5x more planet-heating emissions than official figures show, according to a recent analysis.

Growing Gap In Official and Actual Emissions

Data reveals that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel cars, according to analysis conducted by a advocacy group. That contrasts sharply with laboratory tests, which assumed a 75% decrease in pollution.

Analysts studied data from in-vehicle energy use monitors of 800,000 cars sold in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” stated a lead analyst involved in the report. “This gap is growing and creates a significant problem. As a result, PHEVs pollute nearly as heavily as petrol cars.”

Primary Factors Driving the Emissions Gap

Researchers attributed most of the gap to inflated estimates of the “electric driving share” – the percentage of miles travelled in electric mode relative to total distance. They found that just 27% of driving was completed in electric mode, while lab assumptions suggested 84%.

Even, when operating in electric mode, emission amounts were well above official estimates. That occurred because EV motors were not strong enough to function independently, leading to engines using fossil fuels for almost one-third of the travel covered in electric mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output enabled four major automaker companies to avoid over €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 extra annually in running costs than is assumed under laboratory tests.

“The strong claims that automakers like to make about their PHEV vehicles are obviously far from the truth,” commented a automotive analyst. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving costs. Actually, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running costs.”

Policy Debate and Automotive Lobbying

Hybrid cars have recently been brought again into political discussions as automakers have pressed the European Union to weaken CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced intense pressure from the car industry and resistance from EU countries with large car industries.

Several senior officials have suggested PHEVs as a potential “compromise” solution to include in the legislation.

One external energy economics expert, who was not involved with the research, described the analysis a “very useful addition” after a long period in which parts of the car industry argued there was too little data to properly assess actual emissions.

“The results show, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional cars,” the expert said. “Any regulatory changes concerning PHEVs should be implemented with extreme caution and in the light of that data.”