Abstract:

The potential of plug-in hybrid electric vehicles (PHEVs) to reduce fuel consumption and global greenhouse gas emissions depends on how much they are effectively driven on electricity. Earlier studies on the real-world usage of PHEVs certified under the New European Driving Cycle (NEDC) have shown that those vehicle models are driven much less on electricity than the type-approval procedure assumes. The analysis of the study finds that the real-world fuel consumption of PHEVs in Europe is on average three to five times higher than WLTP type-approval values. The deviation between real-world and type-approval fuel consumption is growing. The deviation from type-approval values is higher for WLTP certified cars than for NEDC vehicles as newer WLTP certified cars show slightly higher average real-world fuel consumption. The average real-world electric driving share is about 45%–49% for private cars and about 11%–15% for company cars. Based on the large-scale empirical evidence, the study presents how the WLTP type-approval assumption on the share of driving in charge-depleting mode (Utility Factor) can be adjusted to better reflect average real-world usage of PHEVs.