PHEV real-world CO2 emissions significantly exceed official test results

An analysis by the organization Transport & Environment, utilizing data from the European Environment Agency, reveals that plug-in hybrid electric vehicles (PHEVs) emit significantly more carbon dioxide in real-world conditions than official laboratory tests suggest.

The study examined approximately 220,000 PHEVs registered in Europe in 2024. While official homologation tests indicate average emissions of around 24 grams of CO2 per kilometer, real-world driving data shows these figures rising to approximately 145 grams per kilometer. This real-world output is only about 14 percent lower than the 169 grams per kilometer average emitted by conventional gasoline or diesel vehicles.

The discrepancy is largely attributed to driving habits. Official tests assume a certain level of electric-only driving, but in practice, drivers do not always charge their batteries frequently enough. When the battery is depleted, the vehicle relies on its internal combustion engine, leading to much higher emissions than advertised.