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PHEVs release almost 5x more planet-heating emissions than lab-reported figures indicate, as per a recent analysis.

Growing Gap In Official and Actual CO2 Output

Statistics reveals that PHEVs emit only 19% less CO₂ than conventional petrol and diesel cars, according to analysis carried out by a non-profit group. This differs significantly with lab estimates, which suggested a three-quarters decrease in pollution.

Analysts examined information from onboard fuel consumption monitors of eight hundred thousand cars registered in the EU from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported figures are falling,” stated a lead analyst involved in the report. “This gap is growing and creates a significant problem. As a result, PHEVs pollute almost as much as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Researchers linked most of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in battery power compared to total mileage. They found that only a quarter of driving was completed in electric mode, while official estimates suggested 84%.

Additionally, when operating in EV mode, emission levels were well above lab projections. That happened because electric motors were not strong enough to function alone, leading to combustion motors burning fossil fuels for nearly one-third of the distance completed in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV CO2 output allowed four large carmaker groups to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs could spend about €500 extra annually in running costs than is estimated under lab conditions.

“The bold statements that automakers often promote about their PHEV vehicles are obviously way off the truth,” stated a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the environment and saving money. In reality, PHEVs are little better than regular gas and diesel cars in terms of energy use, CO₂ production, and running expenses.”

Policy Discussion and Industry Lobbying

Hybrid cars have lately been drawn again into policy discussions as carmakers have pressed the EU to weaken CO₂ targets. A planned prohibition on new internal combustion cars in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with significant car industries.

Some high-level officials have suggested PHEVs as a potential “flexibility” option to include in the regulation.

One external energy policy expert, who was unaffiliated with the research, described the report a “highly valuable addition” after years in which parts of the automotive industry claimed there was too little information to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or diesel vehicles,” they said. “Any regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering that data.”