Work

Real-World CO2 Emissions of Plug-In Hybrid Vehicles: European Assessment Using On-Board Fuel Consumption Monitoring Data

Year: 2026

Type: article

Abstract: Plug-in hybrid electric vehicles (PHEVs) are critical to the EU's decarbonization strategy, yet their real-world climate benefits remain uncertain. This study presents a large-scale analysis of real-world PHEV performance using on-board monitoring data from 457,303 vehicles (2021-2023). The results reveal a profound discrepancy between official test values and actual use. The mean real-world CO₂ emissions were 138 g/km, compared to a test-cycle average of 46 g/km, resulting in a regulatory gap of approximately 300%—significantly higher than for other vehicle types. Performance varied substantially across manufacturers, with gaps ranging over 200 percentage points. Contrary to expectations, larger battery capacity was correlated with a wider performance gap. Real-world electric driving averaged only 45.5% of distance, far below regulatory assumptions. This gap has grown wider each year, indicating test-cycle optimization is outpacing real-world efficiency gains. Policy analysis shows that closing this gap could achieve major CO₂ savings, underscoring the urgent need for regulatory reform, including real-world emissions monitoring and updated test procedures, to ensure PHEVs deliver their promised environmental impact.

Source: Energies

DOI: 10.3390/en19051165

Authors: Maksymilian Mądziel, Tiziana Campisi

Institutions: Rzeszów University of Technology, Università degli Studi di Enna Kore

Language: English

Topic: Vehicle emissions and performance

Subfield: Automotive Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Climate action, Affordable and clean energy, Industry, innovation and infrastructure

Open Access status: gold

Estimated APC paid: $3,137